combinatorial chemistry and synthesis on solid support · pdf filecombinatorial chemistry and...

Combinatorial Chemistry and Synthesis on Solid Support

Burkhard König

University of Regensburg

Outline

I. Solid phase synthesis

1. Polymers, resins, supports2. Linkers3. Analytical techniques

Solid phase synthesis protocols and automatization

4. Peptide Synthesis

a) Protecting groups (- CO2H, -NH2, side chain=

Special topic: Photoremovable protecting groupsb) Coupling methods

5. Oligonucleotides6. Sugars7. Special topic: Immobilization of catalysts

Outline

II. Liquid phase synthesisPolyethylenglycol, Linear Polymers, Isomerization reactions, Metathesis

III. Polymer supported reagents

IV. Combinatorial Chemistry

1. Library synthesisa) in solution, parallel synthesisb) on solid supportc) split and combine, one bead one compound

2. Deconvolution and Tagging3. Dynamic combinatorial Chemistry and virtual libraries

Outline

V. Diversity oriented synthesis (DOS)

Principle and examples

Molecular complexity

VI. Complexity Generating Reactions

Tandem cycloadditions and rearrangements, radical cascade reactions, transition metal catalyzed reactions, mixed tandem reactions, mulit-component reactions

VII. Chemical Diversity

Building blocks, functional groups, stereochemistry,

molecular framework, examples of diversity from biosynthesis

An incomplete list of relevant literature reviews

Current Opinion in Chemical Biology (2000) 4, Issue 4 - available online.

Schreiber, S. L. (2000). Science 287, 1964-1968.

Szostak, J. W. (1997). Introduction: Combinatorial Chemistry. ChemicalReviews 97, 347-348.

Pirrung, M. C. (1997). Spatially Addressable Combinatorial Libraries.Chemical Reviews 97, 473-488.

Osborne, S. E., and Ellington, A. D. (1997). Nucleic Acid Selection and theChallenge of Combinatorial Chemistry. Chemical Reviews 97, 349-370.

Nefzi, A., Ostresh, J. M., and Houghten, R. A. (1997). The Current Status ofHeterocyclic Combinatorial Libraries. Chemical Reviews 97, 449-472.

Pinilla, C., Appel, J., Blondelle, S., Dooley, C., Dorner, B., Eichler, J.,Ostresh, J., and Houghten, R. A. (1995). A Review Of the Utility Of SolublePeptide Combinatorial Libraries. Biopolymers 37, 221-240.

Lam, K. S., Lebl, M., and Krchnak, V. (1997). The''One-Bead-One-Compound'' Combinatorial Library Method. ChemicalReviews 97, 411-448.

Baldwin, J. J., and Henderson, I. (1996). Recent Advances In theGeneration Of Small-Molecule Combinatorial Libraries - Encoded SplitSynthesis and Solid-Phase Synthetic Methodology. Medicinal ResearchReviews 16, 391-405.

Lowe, G. (1995). Combinatorial Chemistry. Chemical Society Reviews 24,329-340.

Terrett, N. K., Gardner, M., Gordon, D. W., Kobylecki, R. J., and Steele, J.(1995). Combinatorial Synthesis - the Design Of Compound Libraries andTheir Application to Drug Discovery. Tetrahedron 51, 8135-8173.

Gallop, M. A., Barrett, R. W., Dower, W. J., Fodor, S. P. A., and Gordon, E.M. (1994). Applications Of Combinatorial Technologies to Drug Discovery .1.Background and Peptide Combinatorial Libraries. Journal Of MedicinalChemistry 37, 1233-1251.

Gordon, E. M., Barrett, R. W., Dower, W. J., Fodor, S. P. A., and Gallop, M.A. (1994). Applications Of Combinatorial Technologies to Drug Discovery .2.Combinatorial Organic Synthesis, Library Screening Strategies, and FutureDirections. Journal Of Medicinal Chemistry 37, 1385-1401.



Szostak, J. W. (1997). Introduction: Combinatorial Chemistry. ChemicalReviews



Szostak, J. W. (1997). Introduction: Combinatorial Chemistry. ChemicalReviews 97, 347-348.


Osborne, S. E., and Ellington, A. D. (1997). Nucleic Acid Selection and theChallenge o

97, 347-348.


Osborne, S. E., and Ellington, A. D. (1997). Nucleic Acid Selection and theChallenge of Combinatorial Chemistry. Chemical Reviews 97, 349-370.

Nefzi, A., Ostresh, J. M., and Houghten, R. A. (1997). The Current Status ofHeterocyclic Combinatorial Libraries. Chemical Reviews 97, 449-472

f Combinatorial Chemistry. Chemical Reviews 97, 349-370.

Nefzi, A., Ostresh, J. M., and Houghten, R. A. (1997). The Current Status ofHeterocyclic Combinatorial Libraries. Chemical Reviews 97, 449-472.

Pinilla, C., Appel, J., Blondelle, S., Dooley, C., Dorner, B., Eichler, J.,Ostresh, J., and Houghten, R. A. (1995). A Review Of the Utility Of SolublePeptide Combinatorial Libraries. Biopolymers 37

.

Pinilla, C., Appel, J., Blondelle, S., Dooley, C., Dorner, B., Eichler, J.,Ostresh, J., and Houghten, R. A. (1995). A Review Of the Utility Of SolublePeptide Combinatorial Libraries. Biopolymers 37, 221-240.


Baldwin, J. J., and Henderson, I. (1996). Recent Advanc

, 221-240.


Baldwin, J. J., and Henderson, I. (1996). Recent Advances In theGeneration Of Small-Molecule Combinatorial Libraries - Encoded SplitSynthesis and Solid-Phase Synthetic Methodology. Medicinal ResearchReviews 16, 391-405.

Lowe, G. (1995). Combinatorial Ch

es In theGeneration Of Small-Molecule Combinatorial Libraries - Encoded SplitSynthesis and Solid-Phase Synthetic Methodology. Medicinal ResearchReviews 16, 391-405.

Lowe, G. (1995). Combinatorial Chemistry. Chemical Society Reviews 24,329-340.

Terrett, N. K., Gardner, M., Gordon, D. W., Kobylecki, R. J., and Steele, J.(1995). Combinatorial Synthesis - the Design Of Compound Libraries andTheir

emistry. Chemical Society Reviews 24,329-340.

Terrett, N. K., Gardner, M., Gordon, D. W., Kobylecki, R. J., and Steele, J.(1995). Combinatorial Synthesis - the Design Of Compound Libraries andTheir Application to Drug Discovery. Tetrahedron 51, 8135-8173.

Gallop, M. A., Barrett, R. W., Dower, W. J., Fodor, S. P. A., and Gordon, E.M. (1994). Applications Of Combinatorial Technologies to Drug Disc

Application to Drug Discovery. Tetrahedron 51, 8135-8173.

Gallop, M. A., Barrett, R. W., Dower, W. J., Fodor, S. P. A., and Gordon, E.M. (1994). Applications Of Combinatorial Technologies to Drug Discovery .1.Background and Peptide Combinatorial Libraries. Journal Of MedicinalChemistry 37, 1233-1251.

Gordon, E. M., Barrett, R. W., Dower, W. J., Fodor, S. P. A., and Gallop, M.A. (1994). Applicati

overy .1.Background and Peptide Combinatorial Libraries. Journal Of MedicinalChemistry 37, 1233-1251.

Gordon, E. M., Barrett, R. W., Dower, W. J., Fodor, S. P. A., and Gallop, M.A. (1994). Applications Of Combinatorial Technologies to Drug Discovery .2.Combinatorial Organic Synthesis, Library Screening Strategies, and FutureDirections. Journal Of Medicinal Chemistry 37, 1385-1401.

Bodanszky, M. (1993). Principles of Peptide Synthesis, 2nd Edition.Springer-Verlag: New York.

Crowley, J. I., Rapoport, H. (1976). Solid-Phase Organic Synthesis: Novelty orFundamental Concept. Accounts of Chemical Research 9, 135 - 144.

Fréchet, J. M. (1981). Synthesis and Applications of Organic Polymers AsSupports and Protecting Groups. Tetrahedron 37, 663 - 683.

Gait, M. J., Ed. (1984). Oligonucleotide Synthesis: A Practical Approach.IRL Press: Washington, D. C.

Letsinger, R. L. (1983). Chemical Synthesis of Oligonucleotides: a SimplifiedApproach. Genetic Engineering 5, 191-207.

Leznoff, C. C. (1974). The Use of Insoluble Polymer Supports in OrganicChemical Synthesis. Chemical Society Reviews 3, 65 - 85.

Leznoff, C. C. (1978). The Use of Insoluble Polymer Supports in GeneralOrganic Synthesis. Accounts of Chemical Research 11, 327 - 333.

Merrifield, B. (1986). Solid Phase Synthesis. Science 232, 341 - 347.(This is a transcript of Merrifield's Nobel Award address.)

Neckers, D. C. (1978). Solid Phase Synthesis. Chemtech, 108 - 116

Overberger, C. G., Sannes, K. N. (1974). Polymeric Reagents in OrganicSynthesis. Angewandte Chemie International Edition in English 13, 99 - 104.

Patchornik, A., Kraus, M. A. (1975). The Use of Polymeric Reagents in OrganicSythesis. Pure and Applied Chemistry 43, 503 - 526.


Crowley, J. I., Rapoport, H. (1976). Solid-Phase Organic Synthesis: Novelty orFundamental Concept


Crowley, J. I., Rapoport, H. (1976). Solid-Phase Organic Synthesis: Novelty orFundamental Concept. Accounts of Chemical Research 9, 135 - 144.


Gait, M. J., Ed.

. Accounts of Chemical Research 9, 135 - 144.


Gait, M. J., Ed. (1984). Oligonucleotide Synthesis: A Practical Approach.IRL Press: Washington, D. C.

Letsinger, R. L. (1983). Chemical Synthesis of Oligonucleotides: a SimplifiedApproach. Genetic Engineering 5,

(1984). Oligonucleotide Synthesis: A Practical Approach.IRL Press: Washington, D. C.

Letsinger, R. L. (1983). Chemical Synthesis of Oligonucleotides: a SimplifiedApproach. Genetic Engineering 5, 191-207.


Leznoff, C. C. (1978). The Use of Insoluble Polymer Sup

191-207.


Leznoff, C. C. (1978). The Use of Insoluble Polymer Supports in GeneralOrganic Synthesis. Accounts of Chemical Research 11, 327 - 333.

Merrifield, B. (1986). Solid Phase Synthesis. Science 232, 341 - 347.(This is a transcript of Merrifield's Nobe

ports in GeneralOrganic Synthesis. Accounts of Chemical Research 11, 327 - 333.

Merrifield, B. (1986). Solid Phase Synthesis. Science 232, 341 - 347.(This is a transcript of Merrifield's Nobel Award address.)


Overberger, C. G., Sannes, K. N. (1974). Polymeric Reagents in OrganicSynthesis. Angewandte Chemie Internation

l Award address.)


Overberger, C. G., Sannes, K. N. (1974). Polymeric Reagents in OrganicSynthesis. Angewandte Chemie International Edition in English 13, 99 - 104.

Patchornik, A., Kraus, M. A. (1975). The Use of Polymeric Reagents in OrganicSythesis. Pure and Applied Chemistry 43, 503 - 526.

I. Solid phase synthesisSynthesis on solid (polymer) support

Why should you care about solid-phase synthesis ?

Even if it were the case that the only successful solid-phase chemistries ever performed were the synthesis of oligopeptides and oligonucleotides, it would be difficult to overstate their importance. These advances created entire new areas of research, and have served as the underpinning for almost all modernbiochemistry and molecular biology.

Two other primary reasons for caring about solid-phase synthesis:

Its interesting!

It served as the basis for much of the early efforts in combinatorial chemistry.

A little history of solid-phase synthesis

Bruce Merrifield1984 Nobel Prize in ChemistryBorn July 21, 1921

1960's: Solid-phase peptide and oligonucleotide synthesis get started.

1970's: Continued development ofsolid-phase peptide and oligosynthesis, including the developmentof effective apparati for automatedsynthesis.

1970's: Synthetic organic chemistsbegin to explore solid-phase organicsynthesis. While interesting, nocompelling case is made for actuallybothering to do organic chemistry onsolid support, and by 1980 mostefforts have stagnated.

1980's: Peptide chemists andbiologists get interested in figuring outhow to make truly huge numbers ofpeptides (and screen them forbiological activity). This leads to thedevelopment of the first combinatoriallibraries.

1980's (late): Interest insolid-phase organic synthesis isrenewed, in both academia and thepharmaceutical industry.Adaptation of "modern" syntheticreactions to the solid-phasebegins.

1990's: Continued improvements in the rate at which potential drugcandidates can be screened (high-throughput screening) lead virtuallyevery major pharmaceutical company to delve into the combinatorialsynthesis of non-peptide, non-oligonucleotide pharmacophores.

1960's: Solid-phase peptide and oligonucleotide synthesis get started.1960's: Solid-phase peptide and oligonucleotide synthesis get started.




1970's: Synthetic organic chemistsbegin to explore solid-phase organicsynthesis. While interesting, nocompelling case is made for actuallybothering to do organic chemistry onsolid support, and



1980's: Peptide chemists andbiologists get interested in figuring outhow to make truly huge numbers ofpeptides (and screen them forbiological activity). This leads to thedevelopment of the firs





1990's: Continued improvements in the rate at which potential drugcandidates can be screened (high-throughput screening) lead virtuallyevery major pharmaceutical company to delve into the combinato


Benefits often associated with solid-phase synthesis

• Minimized Solubility Problems

• Simplified Purification

• Improved Reaction Yields

• Simplified Manipulation of Small Molar Quantities

• Site Isolation

Why Use Solid Phase Synthesis?

SS

SS

SS

SS

S S S S

Purification of compounds bound to the solid support from those in solution is accomplished by simple filtration

This allows the use of a large excess of reagents, improving the efficiency of many transformations

The solid support can be used to compartmentalize library members, permitting the use of split-pool synthesis

1. Polymers, resins, supports

Book Chapters

Barany, G., Kempe, M. (1997). The Context of Solid-Phase Synthesis.In: A Practical Guide to Combinatorial Chemistry. Czarnik, A. W., DeWitt,S. H., Eds. (ACS: Washington, D. C.) Chapter 3.

Früchtel, J. S., Jüng, G. (1996). Polymer Supported Organic Synthesis:A Review. In: Combinatorial Peptide and Non-Peptide Libraries. Jüng,G., Ed. (VCH: New York) Chapter 2.

Novabiochem (2001). The Combinatorial Chemistry Catalog.

Rapp, W. E. (1996). PEG Grafted Polystyrene Tentacle Polymers:Physico-Chemical Properties and Application to Chemical Synthesis. InCombinatorial Peptide and Non-Peptide Libraries. Jüng, G., Ed. (VCH:New York) Chapter 16.

Rapp, W. E. (1997). Macro Beads as Microreactors: New Solid-PhaseSynthesis Methodology. In Combinatorial Chemistry. Wilson, S. R.;Czarnick, A. W., Eds. (Wiley&Sons: New York) Chapter 4.

Review Articles

Vaino, A. R. and Janda, K. D. (2000). Solid-Phase Organic Synthesis: A CriticalUnderstanding of the Resin. Journal of Combinatorial Chemistry, 2, 579-596.

Guillier,F., Orain, D. and Bradley, M. (2000). Linkers and Cleavage Strategies inSolid-Phase Organic Synthesis and Combinatorial Chemistry. ChemicalReviews, 100, 2091-2157.

Book Chapters

Barany, G., Kempe, M. (1997). The Context of Solid-Phase Synthesis.In: A Practical Guide to Combinatorial Chemistry. Czarnik, A. W., DeWitt,S. H., Eds. (ACS: Washington, D

Book Chapters

Barany, G., Kempe, M. (1997). The Context of Solid-Phase Synthesis.In: A Practical Guide to Combinatorial Chemistry. Czarnik, A. W., DeWitt,S. H., Eds. (ACS: Washington, D. C.) Chapter 3.

Früchtel, J. S., Jüng, G. (1996). Polymer Supported Organic Synthesis:A Review. In: Combinatorial Peptide and Non-Peptide Libraries. Jüng,G., Ed. (VCH: New York) Ch

. C.) Chapter 3.

Früchtel, J. S., Jüng, G. (1996). Polymer Supported Organic Synthesis:A Review. In: Combinatorial Peptide and Non-Peptide Libraries. Jüng,G., Ed. (VCH: New York) Chapter 2.


Rapp, W. E. (1996). PEG Grafted Polystyrene Tentacle Polymers:Physico-Chemical Properties and Application to Chemical Synthesis

apter 2.


Rapp, W. E. (1996). PEG Grafted Polystyrene Tentacle Polymers:Physico-Chemical Properties and Application to Chemical Synthesis. InCombinatorial Peptide and Non-Peptide Libraries. Jüng, G., Ed. (VCH:New York) Chapter 16.

Rapp, W. E. (1997). Macro Beads as Microreactors: New Solid-PhaseSynthesis Methodol

. InCombinatorial Peptide and Non-Peptide Libraries. Jüng, G., Ed. (VCH:New York) Chapter 16.

Rapp, W. E. (1997). Macro Beads as Microreactors: New Solid-PhaseSynthesis Methodology. In Combinatorial Chemistry. Wilson, S. R.;Czarnick, A. W., Eds. (Wiley&Sons: New York) Chapter 4.

Review Articles

Vaino, A. R. and Janda, K. D. (2000). Solid-Phase Organic Synthesis: A Cri

ogy. In Combinatorial Chemistry. Wilson, S. R.;Czarnick, A. W., Eds. (Wiley&Sons: New York) Chapter 4.

Review Articles

Vaino, A. R. and Janda, K. D. (2000). Solid-Phase Organic Synthesis: A CriticalUnderstanding of the Resin. Journal of Combinatorial Chemistry, 2, 579-596.

Guillier,F., Orain, D. and Bradley, M. (2000). Linkers and Cleavage Strategies inSolid-Phase Organic Synthesis and Com

ticalUnderstanding of the Resin. Journal of Combinatorial Chemistry, 2, 579-596.

Guillier,F., Orain, D. and Bradley, M. (2000). Linkers and Cleavage Strategies inSolid-Phase Organic Synthesis and Combinatorial Chemistry. ChemicalReviews, 100, 2091-2157.


X Y Z

first resin-boundintermediate, MW = 100

second resin-boundintermediate, MW = 250

final resin-boundintermediate, MW = 400

1.1 g

(9 wt % substrate)

1.25 g

(20 wt % substrate)

1.4 g

(29 wt % substrate)

X Y Z







1.1 g

(9 wt % substrate)

1.1 g

(9 wt % substrate)

1.25 g

(20 wt % substrate)

1.25 g

(20 wt % substrate)

1.4 g

(29 wt % substrate)

1.4 g

(29 wt % substrate)

Typical loading: 1 mmol / g of resin

or 200 pm / bead (for 100 μm aminomethylpolystyrene ~ 5 x 106 beads / g)


Polystyrene Resins

= polystyrene/DVB copolymer(0.5 - 5% cross-linking)

= polystyrene/DVB copolymer(8 - 50% cross-linking)

= polystyrene/Kel-F

= PEPS film

Cheap; excellent chemical stability;good to ca. 110 - 130 °C at 1% DVB;slightly higher at 2% DVB.

Cheap; excellent chemical stability;remarkable thermal and mechanicalstability; very poor swellingcharacteristics → low loadings. Oftencalled "macroreticulate" resin.

Polystyrene grafted onto polyethylenefilm. Improved thermal, mechanicalstability, but lower loading.

Polystyrene ResinsPolystyrene Resins





= polystyrene/Kel-F= polystyrene/Kel-F

= PEPS film= PEPS film








Polyamide Resins

= Pepsyn polyamide,a copolymer of:

H2C H2C

O

NH2

O

HN

NH

O

CH2

NH

HN

O

CH2

O

BocHN

= Pepsyn K Pepsin occluded in keiselguhr (silica)matrix. Excellent longevity; used incontinuous flow SPPS.

Very polar resins; excellent swelling inDMF, H2O; essentially no swelling inCH2Cl2.

Polyamide ResinsPolyamide Resins



H2CH2C H2CH2C

O

NH2NH2

O

HNHN

NHNH

O

CH2CH2

NHNH

HNHN

O

CH2CH2

O

BocHNBocHN

= Pepsyn K= Pepsyn K Pepsin occluded in keiselguhr (silica)matrix. Excellent longevity; used incontinuous flow SPPS.

Pepsin occluded in keiselguhr (silica)matrix. Excellent longevity; used incontinuous flow SPPS.




Polyamide resins (continued)

= Sparrow amide resin,a copolymer of:

H2C H2C

O

N

O

HN

HN

CH3

CH3

O

CH2

H2NCH2

= Polyhipe, a copolymer of the following in amacroreticulate polystyrene/DVB matrix

H2C H2C

O

N

O

NOCH3

CH3

CH3

CH3 O

Polyamide resins (continued)Polyamide resins (continued)



H2CH2C H2CH2C

O

N

O

HNHN

HNHN

CH3CH3

CH3CH3

O

CH2CH2

H2NH2NCH2CH2



H2CH2C H2CH2C

O

N

O

NOCH3OCH3

CH3CH3

CH3CH3

CH3CH3 O


Poly(ethylene glycol) - containing resins

= PEG-PS, PEG covalently graftedonto preformed polystyrene/

1% DVB copolymer

= POE-PS (Tentagel), PEGpolymerized onto

polystyrene/1% DVBcopolymer

Lower mechanical and thermal stabilitythan polystyrene, but much bettersolvent spectrum. (Resin swells inanything but hexanes.)

A couple other resins you might see

HOO

OH

n

= Polyethylene pins, with a grafted crown of:

O O

CH3

n

OH

Poly(ethylene glycol) - containing resinsPoly(ethylene glycol) - containing resins


1% DVB copolymer


1% DVB copolymer







A couple other resins you might seeA couple other resins you might see

HOHOO

OHOH

n

= Polyethylene pins, with a grafted crown of:= Polyethylene pins, with a grafted crown of:

O O

CH3CH3

n

OHOH


Inorganic support materials

Controlled pore glass (CPG); oligonucleotide synthesis

controlled pore ceramics (CPS); high thermal stabilty

Cellulose

Spot synthesis on paper


+

2 - 20 mol%

+

2 - 20 mol%2 - 20 mol%

Cl

Merrifield JACS 1963, 85, 2149.

CH3OCH2Cl

SnCl4

ClCl

Merrifield JACS 1963, 85, 2149.Merrifield JACS 1963, 85, 2149.

CH3OCH2ClCH3OCH2Cl

SnCl4SnCl4

• Cross-Linking imparts mechanical stability and improved diffusion and swelling properties to the resin

Effects of Crosslinking

Without cross-linking, each polymer chain can dissolve under thermodynamically favored conditions

Cross-linking can induce some sites of ‘permanent entanglement’ maintaining structural integrity

Introduction of functional groups

Br

Li

Br2, Tl(III)

n-BuLibetter p- vs o-regioselectivity

n-BuLi,TMEDA

more convenient

BrBr

LiLi

Br2, Tl(III)Br2, Tl(III)



n-BuLi,TMEDA

more convenient

n-BuLi,TMEDA

more convenient

Introduction of functional groups

Li

SCH3

OHPPh2

CO2H

i. O2ii. H–

i. CO2ii. H+

CH3SSCH3

ClPPh2

LiLi

SCH3SCH3

OHOHPPh2PPh2

CO2HCO2H

i. O2ii. H–i. O2ii. H–

i. CO2ii. H+i. CO2ii. H+

CH3SSCH3CH3SSCH3

ClPPh2ClPPh2

For leading references on resin preparations, see the review byFréchet: Tetrahedron 1981, 37, 663.

For leading references on resin preparations, see the review byFréchet: Tetrahedron 1981, 37, 663.

Structure of resins

OH

OH

OH

OH

HO

CH2Cl2

CH2Cl2

CH2Cl2

CH2Cl2

CH2Cl2

CH2Cl2CH2Cl2

CH2Cl210 - 200 μmResin Bead

a few AngstromsBead Section

Structure of a resin bead......

OHOH

OHOH

OHOH

OHOH

HOHO

CH2Cl2CH2Cl2

CH2Cl2CH2Cl2

CH2Cl2CH2Cl2

CH2Cl2CH2Cl2

CH2Cl2CH2Cl2

CH2Cl2CH2Cl2CH2Cl2CH2Cl2

CH2Cl2CH2Cl210 - 200 μm10 - 200 μmResin BeadResin Bead

a few Angstromsa few AngstromsBead SectionBead Section

Structure of a resin bead......Structure of a resin bead......Schematic representation of a macroporous solid-phase supportSchematic representation of a macroporous solid-phase supportSchematic representation of a macroporous solid-phase support

Cl NH2 OH

Br

HOH

O O

Commercially available functional groups grafted onto PS resins

ClCl NH2NH2 OHOH

BrBr

HOHOH

O O

Commercially available functional groups grafted onto PS resinsCommercially available functional groups grafted onto PS resins

Mesh size

Tentagel

PEG-Polystyrene graft polymers

‘Swollen’ state : Permeable to solvent and reagent

‘Shrunken’ state

Swelling of Polymer by Solvent

Swelling properties

Swelling properties of resins

90 μm (TentaGel)0.75 mmol/ g350 pmol/ beadCa. 180 ng/ bead

200 μm (PS)1.05 mmol/ g4 nmol/ beadCa. 2 μg/ bead

500 μm (PS)1.05 mmol/ g60 nmol/ bead

Ca. 30 μg/ bead

Diffusion Efficiency

Practical Considerations in Choosing a Solid Support

• Mode of attachment and cleavage of materials from the resin (linker)

• Compatibility of the chemistry planned for the library synthesis

• The amount of material desired (loading level)

• Size - affects efficiency of diffusion within the polymer (reaction rates!)

• A linker covalently connects molecules to the solid support, and should provide a means for their chemical attachment and cleavage

• Stability of the linker affects the scope of the chemistry that can be employed in the library synthesis

• Many linkers are adapted from protecting group chemistry

Resin Linker

XAttachment

Resin Linker Molecule

Synthetic Steps

Resin Linker Molecule

Cleavage

Molecule

2. Linkers

General structure

Cleavage conditions

Acid-labile benzylalcohol anchors

Amide linkers

Linkers

Benzylic linkers

X= H, Wang linker:

X= OMe, Sasrin linker:

Sieber linker:

Acid Labile Linkers

• Many historically important resins (Merrifield, Wang, Sasrin, Sieber, Rink resins) have linkers that are cleaved under acidic conditions

• Acidic conditions were intended to prevent racemization of amino acids during solid phase peptide synthesis

O

O R

OX

O

NH

R

OO

O

HO R

H2N R

O1-3% TFA

CH2Cl2

CH2Cl2

50% TFA

Linkers

Cleavage by nucleophiles

Catch and release

Nucleophile Labile Linkers

Kaiser Oxime linker

• Advantage: Introduction of diversity in cleavage step

• Difficulty: Often too reactive for common nucleophilic reaction conditions

NO

NO2

R

O

R1 NH2

R1

HN R

O

Linkers

Internal nucleophilic cleavage

Linkers

„Traceless“ linkers

• This type of linker creates a C-C or a C-H bond at the site of cleavage– C-H bond generation : Si-Ge linker (protonolysis or radical reduction)

– C-C bond generation

Ellman J. et al. JOC, 1995, 60, 6006.

Traceless Linkers

Si

NHBn NHBn

H

r.t.

TFA

O

HO

O OR O

N

S Ru

PCy3

PhPCy3Cl

Cl

HO

O OR O

N

S

cat.

Olefin metathesis

Nicolaou KC et al. ACIEE, 1997, 36, 2097.

Ellman J. et al. JACS, 1996, 118, 3055.

Safety-catch linker

Kenner’s sulfonamide linker

• A “safety-catch” linker can solve the reactivity problem with a two step cleavage

• 1) An activation step that is orthogonal to common functional groups

• 2) Cleavage of the activated linker under mild conditions

SNH

R'

O O OS

N R'

O O O

R' NH

O

activation cleavageVery stable

NBr

iPr2NEt, DMSO CN

dilute BnNH2

Bn

Alkylsilyl Linker - Fluoride Labile

Ellman J. et al. JOC, 1997, 62, 6102. Foley MA et al. J. Comb. Chem. 2001, 3, 312.

**

Si

MeMeMe

Me

OMe *

Si

MeMeMe

Me

OMe

Si

MeMeMe

Me

O NHFmoc

*

HO NHFmoc

Br

HO NHFmoc

Tl(OAc)3

Br2/ CH2Cl2

1 % DVB-CL-PS500- 560 um

96 %

127 nmol/ bead

cat. Pd(PPh3)4

NaOH, THF, 40 h

98 %124 nmol/ bead

6.0 eq. TfOH2.0 eq. 2,6-lutidine

1.5 eq.

114 nmol/ bead90 %

1. HF-pyr. THF

2. TMSOMe

B

• Mild cleavage conditions compatible with various functional groups• Designed for attachment through an alcohol

• Compatibile with strong anionic, cationic, oxidative, and reductive conditions

Krafft GA et al. JACS, 1988, 110, 301.

Photo-labile linker

• Photolytic conditions can be very mild and selective

• Dimerization of the support-bound nitroso by-product sometimes hampers further cleavage

• Aryl nitro group is incompatible with some organometallic chemistry

O

MeO

NO2

Me

O

O

R

HO R

O

O

MeO

N

Me

O

O

hν, 350 nm+

2. Linkers - overview

Linkers Cleaved by Strong Acid

HO R

O

Merrifield Resin

Carbamate resin

HO R

O

PAM resin

H2N R

O

BHA resin

Thioester resin

strong acid

HS R

O

O R

O

O NH

O

R

NH

O O

O

R

NH

R

O

NH

O S

O

R

HF, CF3SO3H

HF

RNH2

CF3SO3H

HF

Linkers Cleaved by Strong AcidLinkers Cleaved by Strong Acid

HOHO R

O

Merrifield ResinMerrifield Resin

Carbamate resinCarbamate resin

HOHO R

O

PAM resinPAM resin

H2NH2N R

O

BHA resinBHA resin

Thioester resinThioester resin

strong acidstrong acid

HSHS R

O

O R

O

O NHNH

O

R

NHNH

O O

O

R

NHNH

R

O

NHNH

O S

O

R

HF, CF3SO3HHF, CF3SO3H

HFHF

RNH2RNH2

CF3SO3HCF3SO3H

HFHF

Linkers Cleaved by Moderate Acid

Rink Amide resin (X = NH)Rink Acid resin (X = O)

TFA/CH2Cl2HX R

O

X R

O

OCH3

H3CO

NH

O

O OCH3

OCH3

HN

O

R

PAL resin

moderate

H2N R

O

acid

O

O R

OWang resin

95% TFA

HO R

O

DHPP resin

O

O

O

H3C CH3

O R

O

moderate

HO R

O

acid

Linkers Cleaved by Moderate AcidLinkers Cleaved by Moderate Acid

Rink Amide resin (X = NH)Rink Acid resin (X = O)Rink Amide resin (X = NH)Rink Acid resin (X = O)

TFA/CH2Cl2TFA/CH2Cl2HXHX R

O

X R

O

OCH3OCH3

H3COH3CO

NHNH

O

O OCH3OCH3

OCH3OCH3

HNHN

O

R

PAL resinPAL resin

moderatemoderate

H2NH2N R

O

acidacid

O

O R

OWang resinWang resin

95% TFA95% TFA

HOHO R

O

DHPP resinDHPP resin

O

O

O

H3CH3C CH3CH3

O R

O

moderatemoderate

HOHO R

O

acidacid


Linkers Cleaved by Moderate Acid

PAB resin

NH

O

O

Acid-labile carbamate resin

O

Dihydropyran resin

CHA resin

O

O

NH

O

O

O

O

R

moderate acid

HO R

O

O NH

O

R

moderate

acid

O OR

O

NH R

O

moderate

ac id

H2N R

O

CH3OH, Δ

RNH2

ArSO3HROH

Linkers Cleaved by Moderate AcidLinkers Cleaved by Moderate Acid

PAB resinPAB resin

NHNH

O

O

Acid-labile carbamate resinAcid-labile carbamate resin

O

Dihydropyran resinDihydropyran resin

CHA resinCHA resin

O

O

NHNH

O

O

O

O

R

moderate acidmoderate acid

HOHO R

O

O NHNH

O

R

moderatemoderate

acidacid

O OR

O

NHNH R

O

moderate

ac id

H2NH2N R

O

CH3OH, ΔCH3OH, Δ

RNH2RNH2

ArSO3HArSO3HROHROH

NH

O

O

X

(H3C)3Si

SAL resin (X = NH)SAC resin (X = O)

O

RHX R

Omoderate

acidor F–

Silicon-based Resins

SiO

R RR'

Silyl ether resin

moderate acid

or F–R'OH (R, R = Ph, iPr)

Pbs resin

NH

O

O

HN

Si

O

tBuO

R

O

HO R

O

Ramage resin

NH

O

O

O

RHO R

O

Si(CH3)3

F–

F–

NHNH

O

O

X

(H3C)3Si(H3C)3Si

SAL resin (X = NH)SAC resin (X = O)SAL resin (X = NH)SAC resin (X = O)

O

RHXHX R

Omoderatemoderate

acidor F–acidor F–

Silicon-based ResinsSilicon-based Resins

SiSiO

R RR'R'

Silyl ether resinSilyl ether resin

moderate acidmoderate acid

or F–or F–R'OHR'OH (R, R = Ph, iPr)(R, R = Ph, iPr)

Pbs resinPbs resin

NHNH

O

O

HNHN

SiSi

O

tButBuO

R

O

HOHO R

O

Ramage resinRamage resin

NHNH

O

O

O

RHOHO R

O

Si(CH3)3Si(CH3)3

F–

F–F–


Linkers Cleaved by Weak Acid

XAL resin (Sieber amide resin)

SASRIN resin

O

O

O

O

NH

O

R

H2N R

O

O

O R

O

OCH3 HO R

O

O

O R

Trityl resin (X = H)2-Chlorotrityl resin (X = Cl)

X HO R

O

1% TFA

1% TFA

AcOH

CH2Cl2

CH2Cl2

CH2Cl2

Linkers Cleaved by Weak AcidLinkers Cleaved by Weak Acid

XAL resin (Sieber amide resin)XAL resin (Sieber amide resin)

SASRIN resinSASRIN resin

O

O

O

O

NHNH

O

R

H2NH2N R

O

O

O R

O

OCH3OCH3 HOHO R

O

O

O R

Trityl resin (X = H)2-Chlorotrityl resin (X = Cl)Trityl resin (X = H)2-Chlorotrityl resin (X = Cl)

X HOHO R

O

1% TFA1% TFA

1% TFA1% TFA

AcOHAcOH

CH2Cl2CH2Cl2

CH2Cl2CH2Cl2

CH2Cl2CH2Cl2

Linkers Cleaved by Base or Nucleophiles

NH

O

N

OCH3

O

R R'MgCl

R' R

O

Weinreb amide resin

LAH

H R

O

NH

O

NO2

O

O

Rpiperidine

HO R

O

NPE resin

NH

Fm resin

Opiperidine

HO R

O

NH

HMFA resin

O

OR

O

O

O

Rpiperidine

HO R

O

Linkers Cleaved by Base or NucleophilesLinkers Cleaved by Base or Nucleophiles

NHNH

O

N

OCH3OCH3

O

R R'MgClR'MgCl

R'R' R

O

Weinreb amide resinWeinreb amide resin

LAHLAH

H R

O

NHNH

O

NO2NO2

O

O

Rpiperidinepiperidine

HOHO R

O

NPE resinNPE resin

NHNH

Fm resinFm resin

Opiperidinepiperidine

HOHO R

O

NHNH

HMFA resinHMFA resin

O

OR

O

O

O

Rpiperidinepiperidine

HOHO R

O


Linkers Cleaved by Base or Nucleophiles

X

O

R

Let's not forget Merrifield resin...

R'OH, base

R'O R

O

LAH

HO R'

X = O, S

Linkers Cleaved by Base or NucleophilesLinkers Cleaved by Base or Nucleophiles

X

O

R

Let's not forget Merrifield resin...Let's not forget Merrifield resin...

R'OH, baseR'OH, base

R'OR'O R

O

LAHLAH

HOHO R'R'

X = O, SX = O, S

NH

NH

S

O

O

O

OR

O O

OR

Finally, a couple derived from early oligo work

NH4OHROH

NH4OHROH

NHNH

NHNH

S

O

O

O

OROR

O O

OROR

Finally, a couple derived from early oligo workFinally, a couple derived from early oligo work

NH4OHNH4OHROHROH

NH4OHNH4OHROHROH

Photocleavable Linkers

NH

O

ONb resin (X = O)Nonb resin (X = NH)

X

NO2

R

O

hν

wet CH3CNHX R

O

NH

Holmes resin (X = O, NH)

O

O

NO2

OCH3

CH3

X R

O

hνHX R

O

O

CH3

O R

O

hνHO R

O

α-Methylphenacyl ester resin

NH

NH

O

Geysen resin

hν

wet CH3CNH2N R

O

Brown, B. B., Wagner, D. S., and Geysen, H. M. (1995). Molecular Diversity 1, 4-12.

RO

NO2

Photocleavable LinkersPhotocleavable Linkers

NHNH

O

ONb resin (X = O)Nonb resin (X = NH)ONb resin (X = O)Nonb resin (X = NH)

X

NO2NO2

R

O

hνhν

wet CH3CNwet CH3CNHXHX R

O

NHNH

Holmes resin (X = O, NH)Holmes resin (X = O, NH)

O

O

NO2NO2

OCH3OCH3

CH3CH3

X R

O

hνhνHXHX R

O

O

CH3CH3

O R

O

hνhνHOHO R

O

α-Methylphenacyl ester resinα-Methylphenacyl ester resin

NHNH

NHNH

O

Geysen resinGeysen resin

hνhν

wet CH3CNwet CH3CNH2NH2N R

O

Brown, B. B., Wagner, D. S., and Geysen, H. M. (1995). Molecular Diversity 1, 4-12.Brown, B. B., Wagner, D. S., and Geysen, H. M. (1995). Molecular Diversity 1, 4-12.

RO

NO2NO2


"Traceless" Linkers

O

Veber's resin

O Si

O

Showalter's resin

NH

O

Ellman's resin

Janda's resin

O

OSi

RCH3

H3C

R

strong acid

H3C CH3

R

R

strong acid

or F–

Si

iPr iPr

R Rstrong acid

or F–

O

O

NH

CF3

SR

Bu3SnH, AIBN, Δ

or Raney Ni, H2

H R

Janda, et al. (1996). Tetrahedron Letters 37, 6491-6494.

"Traceless" Linkers"Traceless" Linkers

O

Veber's resinVeber's resin

O SiSi

O

Showalter's resinShowalter's resin

NHNH

O

Ellman's resinEllman's resin

Janda's resinJanda's resin

O

OSiSi

RCH3CH3

H3CH3C

R

strong acid

H3CH3C CH3CH3

R

R

strong acidstrong acid

or F–or F–

SiSi

iPriPr iPriPr

R Rstrong acidstrong acid

or F–or F–

O

O

NHNH

CF3CF3

SR

Bu3SnH, AIBN, ΔBu3SnH, AIBN, Δ

or Raney Ni, H2or Raney Ni, H2

H R

Janda, et al. (1996). Tetrahedron Letters 37, 6491-6494.Janda, et al. (1996). Tetrahedron Letters 37, 6491-6494.

Kenner's "safety catch" resin

SNH

O O O

Ri CH2N2

ii HO–HO R

O

SCAL resin

NH

O

O HN

S S

O

H3C

O

CH3

O

R

(CH3)3SiCl, PPh3or

(EtO)2P(S)SHH2N R

OTFA

DSB resin

NH

O

O

S

H3C

CH3

R

O

H3C O

HO R

O

ii TFA

i (CH3)3SiCl, PPh3

Kenner's "safety catch" resinKenner's "safety catch" resin

SNHNH

O O O

Ri CH2N2i CH2N2

ii HO–ii HO–HOHO R

O

SCAL resinSCAL resin

NHNH

O

O HNHN

S S

O

H3CH3C

O

CH3CH3

O

R

(CH3)3SiCl, PPh3or

(EtO)2P(S)SH

(CH3)3SiCl, PPh3or

(EtO)2P(S)SHH2NH2N R

OTFATFA

DSB resinDSB resin

NHNH

O

O

S

H3CH3C

CH3CH3

R

O

H3CH3C O

HOHO R

O

ii TFAii TFA

i (CH3)3SiCl, PPh3i (CH3)3SiCl, PPh3

3. Analytical techniques

Off bead analysis

• Cleavage, then use of conventional analytical techniques (e.g. LC, MS, NMR)• Requires high sensitivity and high throughput format

Example: LC-UV/ MSS

OH OH

N

O

HOPh

Ph

Kaiser test

On bead analysis

1) Colorimetric methods, Kaiser test

Kaiser test

On bead analysis

1) Colorimetric methods, Kaiser test

NMR

On bead analysis

2) MAS-NMR ( Magic angle spinning NMR )

Magic angle rotor (left), rotor spinning at the magic angle (right)

OO

Si

O

O

OMe

O

OOO

MAS- NMR spectrum (600 MHz)

Single bead IR

On bead analysis

3) Single-bead FT-IR microspectrometry

O

O

DIC, DMAP, DMFO

O

O OH

HO

O O

Beads in IR cell

Wavelength(cm-1)

4. Peptide Synthesis

Insulin

Protecting groups for -NH2

Benzoyloxycarbonyl groupCarbobenzoxy (Cbo) or Z (Zervas) group

Introduction


Benzoyloxycarbonyl groupCarbobenzoxy (Cbo) or Z (Zervas) group

Cleavage


Tert-Butoxycarbonyl group (Boc)

Introduction

Di-tert-butyl-biscarbonatePyrocarbonate


Cleavage

tert-Butoxycarbonyl group (Boc)

TFA


Introduction: Fmoc-Cl, Fmoc-Suc

Fluorenyl-9-methoxycarbonyl group (Fmoc)

Cleavage

Protecting groups for -COOH

All kinds of esterscleavage

Protecting groups for -COOH

Carboxyl protecting groups which can be activated for coupling

hydrazide carbamate

transform into azide

Protecting groups for side chain functional groups

Guanodinium group

Di-acylation or nitration;No perfect protecting group available


Imidazole

Amino protecting groupsProtection often necessary to increasesolubility.

H

cleavage


Thiole

Strong nucleophile, easily oxidized – must be protected in peptide synthesis.

cleavage


Hydroxy groups

Protection usually not necessary in peptide synthesis. Exceptions: Large excess of amino acid used; solubility reasons

cleavage


Indole, thioether

Protection usually not necessary in peptide synthesis. Caution: Alkylation of thioether by carbenium ion possible


Amides

Protection usually not necessary in peptide synthesis. Exception: Amides with solubility problems; cyclization as side reaction


ϖ-Amino- and carboxy groups

Differentiation between α- and ϖ-functional groups necessary


ϖ-Amino- and carboxy groups

Special topic: Photocleavable protecting groups and linkers

Norrish-type II: ortho-nitrobenzyl alcohols

C. G. Bochet, J. Chem. Soc., Perkin Trans. 1 2002, 125 - 142.

Photocleavable protecting groups





Different reaction pathway iffunctional group to be protected islinked in β-position




Protecting group for ketones:



Array synthesis:


Norrish-type II: Phenacyl esters

Protection of acids.Fast release trigger forbiological stimulants.


RO

OH


Norrish-type II: Phenacyl esters

Photolabile linkers and resins

F. Guiller, D. Orain, M. Bradley, Chem. Rev. 2000, 100, 2091 - 2157.

Photocleavable linkers

F. Guiller, D. Orain, M. Bradley, Chem. Rev. 2000, 100, 2091 - 2157.


Current developments

Selective deprotectionby light of differentwavelength

M. Kessler, R. Glatthar, B. Giese, C.G. Bochet, Org. Lett. 2003, 5, 1179 - 1181.




Selective deprotectionby light of differentwavelength

Coupling methods

Azide coupling: No racemization, but very slow

Coupling methods

Anhydride and mixed anhydride method

Wrong way !

Coupling methods

sym anhydride method

Maximum yield: 50 % !

Coupling methods

N-Carboxylic acid anhydride method

1,3-Oxazolidin-2,5-dione

Peptide synthesis in aqueoussolution

Repeat steps

Coupling methods

Carbodiimide method (DCC, EDC)

DCC in situ activeEster formation withadditives

Coupling methods

Active esters

Synthesis of cyclic peptides

PFP esterring closure

Coupling methods

Active ester: 8-Chinolyl ester as internal base

Coupling methods

In situ formation of active esters

Expensive reagents !

Coupling methods

Segment coupling – native chemical ligation

Coupling methods

Segment coupling – native chemical ligation

Synthesis of interleukin 8(IL-8)

Solution synthesis of large peptides

Sakakibara strategy: Pac = Phenylacyl ester; WSCI = water soluble carbodiimide

Solution synthesis of large peptides

Sakakibara strategy: How far can we go?

Purification and characterisation of peptides

Typical analytical methods

Solid phase synthesis protocols

Merrifield synthesis

PAM anchor group

PAM anchor

Automated peptide synthesis

Protecting group tactics

Boc/Bzl

MBHA = p-methyl benzhydrylamide anchor

Protecting group tactics

Fmoc/tBu

Anchor groups in solid phase peptide synthesis

cleavage

Racemization during peptide synthesis

Enol formation


Oxazolonmechanism


Coupling reagents

Biochemical peptide synthesis

Transformation ofmRNA into DNA


Schematic procedurefor preparationof recombinant proteins


Recombinant proteinsIn medicinal chemistry

5. Oligonucleotides

Nucleotides

Nucleosides

Phosphorylated Nucleosides

Oligonucleotide

DNA double strand – B DNA

DNA double strand – A DNA

Physical parameters of nucleobases

Tautomeres ?

Watson – Crick Basenpairing

C - G T - A

Reversed Watson – Crick Basepairing

Wooble Basenpairing

T - A

U - G

Shifted by oneposition

Hoogsteen Basenpairing

A - T A - T

Watson-Crickhydrogen bondacceptor site

Oligonucleotide Synthesis

Synthesis of nucleosides

Route A

Route A – Hilbert Johnson reaction

Route A – Hilbert Johnson reaction

Route A – Silyl Hilbert Johnson reaction

Route A – Silyl Hilbert Johnson reaction

reactions at differentpositions possible

Route A – Silyl Hilbert Johnson reaction (2nd example)

Route B

Route C – assembly of the nuclobase

Route to a non-naturalFlavin nucleobase

Route C

Pseudo-Uridine

Wyosine

Stereoselective synthesis of α- and β-nucleosides

Selective β-nucleoside synthesis


β-nucleoside


Selective α-nucleoside synthesis

Synthesis of nucleotides and oligonucleotides

Chemistry of phosphoric and phosphinic acid esters

Hydrolysis of phosphoric acid triesters

Hydolysis of phosphoric acid triesters

Synthesis of phosphoric acid esters

Phosphoramidite route

H-Phosphonate route

Automated DNA synthesis

First nucleotide in DNA synthesis

Automated DNA synthesis

Each nucleotide addition requires four steps1. Detritylation2. Activation and Coupling3. Capping4. Oxidation

Repeat steps for next nucleotide

Phosphoramidite

Detritylation

The dimethoxy-trityl protecting group of the 5´-OH group needs to be removed, so that the next base can be added. Trichloroacetic acid (TCA) is used as reagentfor cleavage.

Activation and coupling

Protonation activates the leaving group

Activation and coupling

Capping

To prevent uncoupled nucleotides from reacting in the next step, which leadsto wrong sequence

Oxidation

How far can we go ?

DNA synthesis: 100 nanomole scale*

Nominal charge, couldbe as low as US $ 3.00 (see "S&H")

US $ 0.29 per base, no setup fee

All other countries

From CAN $ 1.00 to CAN $ 18 (see "S&H")

CAN $ 0.39 per base, no setup fee

Canada

From US $ 1.00 to US $ 18.00 (see "S&H")

US $ 0.29 per base, no setup fee

USA

Shipping and handlingPrice per base**(no setup fee!)

Customer'scountry

*Only customers with accounts in good standing are eligible for this scale. All orders at the 100 nmole scale must be placedusing our special order form in Microsoft Excel format, please e-mail us your request. 100 nmole (0.1 micromole) synthesisscale will yield typically 0.040-0.150 micromole (40-150 nmole) final product for a regular size, standard purity oligo.Guaranteed minimum 40 nmole for regular size (up to 25-mer) oligos, standard purity (desalted). For longer oligos, 9 OD260 guaranteed minimum (standard purity). Standard purity includes free desalting. All oligos are quantified and three different units of measure are provided to the customer. The relation between these three units is calculated by a computer, but as an approximation for a 20 base long oligo, 50 nmole equals approx. 10 OD260 units or 300 microgram.

**Oligos longer than 35 bases, which are ordered without additional purification, will be supplied with no replacementwarranty.

Commercial suppliers

Synthesis of a synthetic gene



Washington Post, July 17, 2002

Synthesis of phosphate monoesters

Pyrophosphates of biological relevance

Synthesis of pyrophosphates

Biochemical methods - The principle of PCR

Denaturation at 94°C

Annealing at 54°C

The three major steps:

Extension at 72°C



Use of PCR in in vitro random selection

DNA strand

known sequencerandom sequence

SELEX = systematic evolution of ligands by experimental enrichtment

Use of PCR in in vitro random selection

Aptamere

Intramere

Ribozyme

Aptamere

Didesoxy DNA sequencing

DNA strand to be sequenced

template strand, labeled with 32P

reaction vessel withdidesoxythymidine-5´-triphosphate

reaction vessel withdidesoxycytidine-5´-triphosphate


Long oligo´s5´

Short oligo´s3´

Yellow = CGreen = GRed = TBlue = A


DNA chips

in complexmixture

6. Sugars

Protecting groups in carbohydrate synthesis

Protecting groups in carbohydrate synthesis

Transglycosylation

Transglycosylation

OR

OR

Trichloroacetamidate activation

Thermodynamic controlled reaction:α-anomere; anomeric effect

Kinetically controlled reaction:β-anomere

R.R. Schmidt, W. Kinzy, Adv, Carbohydr. Chem. Biochem. 1994, 50, 21.

Thioglycosides

Activation of a protected glycoside

Oligosaccharide synthesis

Segement synthesis and coupling

Oligosaccharide synthesis

Examples of Solid phase oligosaccharide synthesis

Danishefsky's Strategies for SPS of Oligosaccharides - Cartoon Form

Danishefsky, et al. (1995). A Strategy for a Convergent Synthesis of N-LinkedGlycopeptides on a Solid Support. Science 169, 202 - 204.

Danishefsky, et al. (1995). Major Simplifications in Oligosaccharide SynthesesArising from a Solid-Phase Based Method: An Application to the Synthesis ofthe Lewis b Antigen. Journal of the American Chemical Society 117, 5712 -5719.

Danishefsky's Strategies for SPS of Oligosaccharides - Cartoon FormDanishefsky's Strategies for SPS of Oligosaccharides - Cartoon Form




Danishefsky, et al. (1995). Major Simplifications in Olig



O

O

PO

PO

O

O

PO

PO

O

OHO

PO

PO

O

O

PO

PO HO

O

O

PO

PO

O

O

PO

PO HO

O

O

PO

PO

O

O

O

PO

PO HO

O

O

PO

PO OH

O

O

OP

PO

OPO

PO

HOEtc.

O

O

POPO

POPO

O

O

POPO

POPO

O

OHOHO

POPO

POPO

O

O

POPO

POPO HOHO

O

O

POPO

POPO

O

O

POPO

POPO HOHO

O

O

POPO

POPO

O

O

O

POPO

POPO HOHO

O

O

POPO

POPO OHOH

O

O

OPOP

POPO

OPOPO

POPO

HOHOEtc.Etc.

Si(iPr)2Cl

Home-madepolystyrenederivative

OO

O

O

OO

O

O

OH

Si

OO

O

O

O

iPriPr

CH2Cl2, iPr2NEtDMAP

OO

H3C

CH3

Si

OO

O

O

O

iPriPr

O

H

H

OO

O

O

OH

ZnCl2, THF

Si

O

iPriPr

O

O

O

O

HO OO

O

O

Si

O

iPriPr

O

O

O

O

HO

OO

H3C

CH3

O

H

H

OO

O

O

OH

ZnCl2, THF

OO

H3C

CH3

OO

Si(iPr)2ClSi(iPr)2Cl



OO

O

O

OO

O

O

OHOH

SiSi

OO

O

O

O

iPriPriPriPr

CH2Cl2, iPr2NEtDMAP

CH2Cl2, iPr2NEtDMAP

OO

H3CH3C

CH3CH3

SiSi

OO

O

O

O

iPriPriPriPr

O

H

H

OO

O

O

OHOH

ZnCl2, THFZnCl2, THF

SiSi

O

iPriPriPriPr

O

O

O

O

HOHO OO

O

O

SiSi

O

iPriPriPriPr

O

O

O

O

HOHO

OO

H3CH3C

CH3CH3

O

H

H

OO

O

O

OHOH

ZnCl2, THFZnCl2, THF

OO

H3CH3C

CH3CH3

OO

Si

O

iPriPr

O

O

O

O

HOO

O

O

O

O

HOO

O

O

O

O

1) DMDO, DCM

2) ZnCl2, THF

OO

OPh

HO

Si

O

iPriPr

O

O

O

O

HOO

O

O

O

O

HOO

O

O

O

O

OH

OO

OPh

O

1) DMDO, DCM

2) ZnCl2, THF

OO O

OHBnO

BnO

OBn BnO

OBn

Si

O

iPriPr

O

O

O

O

HOO

O

O

O

O

HOO

O

O

O

O

OH

OO

OPh

O

OO O

OBnO

BnO

OBn BnO

OBnHO

Cleaved from resin by treatmentwith TBAF/AcOH in MeOH

SiSi

O

iPriPriPriPr

O

O

O

O

HOHOO

O

O

O

O

HOHOO

O

O

O

O

1) DMDO, DCM1) DMDO, DCM

2) ZnCl2, THF2) ZnCl2, THF

OO

OPhPh

HOHO

SiSi

O

iPriPriPriPr

O

O

O

O

HOHOO

O

O

O

O

HOHOO

O

O

O

O

OHOH

OO

OPhPh

O

1) DMDO, DCM1) DMDO, DCM

2) ZnCl2, THF2) ZnCl2, THF

OO O

OHOHBnOBnO

BnOBnO

OBnOBn BnOBnO

OBnOBn

SiSi

O

iPriPriPriPr

O

O

O

O

HOHOO

O

O

O

O

HOHOO

O

O

O

O

OHOH

OO

OPhPh

O

OO O

OBnOBnO

BnOBnO

OBnOBn BnOBnO

OBnOBnHOHO

Cleaved from resin by treatmentwith TBAF/AcOH in MeOHCleaved from resin by treatmentwith TBAF/AcOH in MeOH

OH

Solid-Phase Synthesis of a Heptasaccharide Phytoalexin Elicitor

OO

NO2

OO

Nicolaou, et al. (1997). A General and Highly Efficient Solid Phase Synthesis ofOligosaccharides. Total Synthesis of a Heptasaccharide Phytoalexin Elicitor.Journal of the American Chemical Society 119, 449 - 450.

OBzBzO

BzO

OTDS

Home-made polystyrenederivative

OO

OBzBzO

BzO

OTDS

OHO

OBzBzO

BzO

OTDS

hν, THF

95%

CsCO3, DMF

> 90% by mass gain

O

OH

HOHO

HO

OHO

OH

HOHO

O O

OHHO

OO

OH

HOHOHO

O O

OH

HOHO

O O

OHHO

O

OO

OH

HOHOHO

I

O

O2N

An example utilizing thioglycoside donors.........

OHOH

Solid-Phase Synthesis of a Heptasaccharide Phytoalexin ElicitorSolid-Phase Synthesis of a Heptasaccharide Phytoalexin Elicitor

OO

NO2NO2

OO


Nicolaou, et al. (1997). A General and Highly Efficient Solid Phase Synthesis ofOligosaccharides. Total Synthesis of a Heptasaccharide Phytoalexin Elicitor.Journal of the American Chemi


OBzOBzBzOBzO

BzOBzO

OTDSOTDS



OO

OBzOBzBzOBzO

BzOBzO

OTDSOTDS

OHOHO

OBzOBzBzOBzO

BzOBzO

OTDSOTDS

hν, THFhν, THF

95%95%

CsCO3, DMFCsCO3, DMF

> 90% by mass gain> 90% by mass gain

O

OHOH

HOHOHOHO

HOHO

OHOHO

OHOH

HOHOHOHO

O O

OHOHHOHO

OO

OHOH

HOHOHOHOHOHO

O O

OHOH

HOHOHOHO

O O

OHOHHOHO

O

OO

OHOH

HOHOHOHOHOHO

I

O

O2NO2N

An example utilizing thioglycoside donors.........An example utilizing thioglycoside donors.........

O

O

OBzBzO

BzO

OTBDPS

OOAc

OAcAcO

AcO

OAc

OSPh

OAcAcO

AcO

OAcO

SPhOBz

BzOBzO

OTBDPS

OSPh

OBzFmocOBnO

OTBDPSThe Monomers

i. HF•Py, THF

ii. DMTST, 4AMS, Aiii. NEt3, CH2Cl2

O

O

OBzBzO

BzO

O

OOBz

HOBnO

OTBDPS

i. DMTST, 4AMS, B

ii. HF•Py, THF

O

OBzBzO

BzO

O

O

OBz

BnOO

O

OAcAcO

AcOAcO

i. DMTST, 4AMS, C

ii. HF•Py, THF

OH

The Iterative HPE Synthesis

O

NO2

O

O

NO2

O

O

NO2

O

A

B

C

O

O

OBzOBzBzOBzO

BzOBzO

OTBDPSOTBDPS

OOAcOAc

OAcOAcAcOAcO

AcOAcO

OAcOAc

OSPhSPh

OAcOAcAcOAcO

AcOAcO

OAcOAcO

SPhSPhOBzOBz

BzOBzOBzOBzO

OTBDPSOTBDPS

OSPhSPh

OBzOBzFmocOFmocOBnOBnO

OTBDPSOTBDPSThe MonomersThe Monomers

i. HF•Py, THFi. HF•Py, THF



O

O

OBzOBzBzOBzO

BzOBzO

O

OOBzOBz

HOHOBnOBnO

OTBDPSOTBDPS

i. DMTST, 4AMS, Bi. DMTST, 4AMS, B

ii. HF•Py, THFii. HF•Py, THF

O

OBzOBzBzOBzO

BzOBzO

O

O

OBzOBz

BnOBnOO

O

OAcOAcAcOAcO

AcOAcOAcOAcO

i. DMTST, 4AMS, Ci. DMTST, 4AMS, C


OHOH

The Iterative HPE SynthesisThe Iterative HPE Synthesis

O

NO2NO2

O

O

NO2NO2

O

O

NO2NO2

O

A

B

C

O

OBzBzO

BzO

O

O

OBz

BnOO

O

OAcAcO

AcOAcO

O

OOBz

BzOBzO

OH

i. DMTST, 4AMS, A

ii. NEt3, CH2Cl2

O

OBzBzO

BzO

O

O

OBz

BnOO

O

OAcAcO

AcOAcO

O

OOBz

BzOBzO

O

OOBz

HOBnO

OTBDPS

i. DMTST, 4AMS, B

ii. HF•Py, THF

O

OBzBzO

BzO

O

O

OBz

BnOO

O

OAcAcO

AcOAcO

O

OOBz

BzOBzO

O

OOBz

BnO

OH

OO

OAcAcO

AcO

OAc

DMTST, 4AMS, B

O

NO2

O

O

NO2

O

O

NO2

OO

OBzOBzBzOBzO

BzOBzO

O

O

OBzOBz

BnOBnOO

O

OAcOAcAcOAcO

AcOAcOAcOAcO

O

OOBzOBz

BzOBzOBzOBzO

OHOH

i. DMTST, 4AMS, Ai. DMTST, 4AMS, A

ii. NEt3, CH2Cl2ii. NEt3, CH2Cl2

O

OBzOBzBzOBzO

BzOBzO

O

O

OBzOBz

BnOBnOO

O

OAcOAcAcOAcO

AcOAcOAcOAcO

O

OOBzOBz

BzOBzOBzOBzO

O

OOBzOBz

HOHOBnOBnO

OTBDPSOTBDPS

i. DMTST, 4AMS, Bi. DMTST, 4AMS, B


O

OBzOBzBzOBzO

BzOBzO

O

O

OBzOBz

BnOBnOO

O

OAcOAcAcOAcO

AcOAcOAcOAcO

O

OOBzOBz

BzOBzOBzOBzO

O

OOBzOBz

BnOBnO

OHOH

OO

OAcOAcAcOAcO

AcOAcO

OAcOAc

DMTST, 4AMS, BDMTST, 4AMS, B

O

NO2NO2

O

O

NO2NO2

O

O

NO2NO2

O

O

OAcAcO

AcO

OAc

O

OBzBzO

BzO

O

OOBz

BnOO O

OAcAcO

AcOAcO

O

OOBz

BzOBzO

O

OOBz

BnO

O

OO

OAcAcO

AcOAcO

i. hν, THF

ii. Ac2O, NEt3

O

OAcAcO

AcO

OAc

OAcO

OBzBzO

BzO

O

OOBz

BnOO O

OAcAcO

AcOAcO

O

OOBz

BzOBzO

O

OOBz

BnO

O

OO

OAcAcO

AcOAcO

ca. 20% overall fromfirst resin-bound sugar!

protected solid-phaseoligosaccharide

i. hν, THF

ii. NaOCH3, CH3OHiii. H2, Pd, CH3OH

95% for two steps

O

NO2

O

O

OAcOAcAcOAcO

AcOAcO

OAcOAc

O

OBzOBzBzOBzO

BzOBzO

O

OOBzOBz

BnOBnOO O

OAcOAcAcOAcO

AcOAcOAcOAcO

O

OOBzOBz

BzOBzOBzOBzO

O

OOBzOBz

BnOBnO

O

OO

OAcOAcAcOAcO

AcOAcOAcOAcO

i. hν, THFi. hν, THF

ii. Ac2O, NEt3ii. Ac2O, NEt3

O

OAcOAcAcOAcO

AcOAcO

OAcOAc

OAcOAcO

OBzOBzBzOBzO

BzOBzO

O

OOBzOBz

BnOBnOO O

OAcOAcAcOAcO

AcOAcOAcOAcO

O

OOBzOBz

BzOBzOBzOBzO

O

OOBzOBz

BnOBnO

O

OO

OAcOAcAcOAcO

AcOAcOAcOAcO

ca. 20% overall fromfirst resin-bound sugar!ca. 20% overall fromfirst resin-bound sugar!



i. hν, THFi. hν, THF

ii. NaOCH3, CH3OHiii. H2, Pd, CH3OHii. NaOCH3, CH3OHiii. H2, Pd, CH3OH

95% for two steps95% for two steps

O

NO2NO2

O

2) Strategies Utilizing Support-Bound Acceptors

O

Glycosyl sulfoxides

S

PivO

PivO

PivO

OH

O

O

PivO

PivO

PivO

OTr

SPh

O

Tf2O, DTBMP-78 to -60 oC

OS

PivO

PivO

PivO O

O

PivO

PivO

PivO

OTr

O

1. TFA

2.

O

PivO

PivO

PivO

OTr

SPh

O

Tf2O, DTBMP-78 to -60 oC

OS

PivO

PivO

PivO O

O

PivO

PivO

PivO

O

O

PivO

PivO

PivO

OTr

O

Cleavage from resinachieved with:

Hg(OCOCF3)2, water,RT, 5 h> 50 % overall yield

> Coupling efficiency believedto exceed 90%; resin cleavage ~70-75%

Yan, L.; Taylor, C. M.; Goodnow, R.; Kahne, D. J. Am. Chem. Soc. 1994, 116, 6953.

2) Strategies Utilizing Support-Bound Acceptors2) Strategies Utilizing Support-Bound Acceptors

O

Glycosyl sulfoxidesGlycosyl sulfoxides

S

PivOPivO

PivOPivO

PivOPivO

OHOH

O

O

PivOPivO

PivOPivO

PivOPivO

OTrOTr

SPhPh

O

Tf2O, DTBMP-78 to -60 oCTf2O, DTBMP-78 to -60 oC

OS

PivOPivO

PivOPivO

PivOPivO O

O

PivOPivO

PivOPivO

PivOPivO

OTrOTr

O

1. TFA1. TFA

2.2.

O

PivOPivO

PivOPivO

PivOPivO

OTrOTr

SPhPh

O

Tf2O, DTBMP-78 to -60 oCTf2O, DTBMP-78 to -60 oC

OS

PivOPivO

PivOPivO

PivOPivO O

O

PivOPivO

PivOPivO

PivOPivO

O

O

PivOPivO

PivOPivO

PivOPivO

OTrOTr

O


Hg(OCOCF3)2, water,RT, 5 h


Hg(OCOCF3)2, water,RT, 5 h> 50 % overall yield

> Coupling efficiency believedto exceed 90%; resin cleavage ~70-75%

> 50 % overall yield> Coupling efficiency believed

to exceed 90%; resin cleavage ~70-75%

Yan, L.; Taylor, C. M.; Goodnow, R.; Kahne, D. J. Am. Chem. Soc. 1994, 116, 6953.Yan, L.; Taylor, C. M.; Goodnow, R.; Kahne, D. J. Am. Chem. Soc. 1994, 116, 6953.

Kahne, D., et al. (1996). Parallel Synthesis and Screening of a Solid PhaseCarbohydrate Library. Science 274, 1520 - 1522.

OO

O

OH

HO

OH OHOH

OH NHAc

OHThe known antigen for Bauhinia purpurea lectin:

NH2 PEG-PS(Tentagel) HOBt, HBTU, NMP

S O

O

HN

AcO OO

O

N3

S O CO2H

Ph

HOO

OO

N3

Ph

O

PivO

PivO

OPiv

PivO

OS

PivO

PivO

OPiv

PivOPh

O

TfOH, THF, –65 °C

S O

O

HN

OO

OO

N3

Ph

i. P(CH3)3, THFii. AcCl, NEt3,

CH2Cl2

iii. 20% TFA/CH2Cl2iv. LiOH, THF,

CH3OH

OO

O

OH

HO

OH OHOH

OH NHAc

S O

O

HN

Combinatorial Synthesis of a Disaccharide Library

H2NNH2

DMF



OO

O

OHOH

HOHO

OHOH OHOHOHOH

OHOH NHAcNHAc

OHOHThe known antigen for Bauhinia purpurea lectin:The known antigen for Bauhinia purpurea lectin:

NH2NH2 PEG-PS(Tentagel)PEG-PS

(Tentagel) HOBt, HBTU, NMPHOBt, HBTU, NMP

S O

O

HNHN

AcOAcO OO

O

N3N3

S O CO2HCO2H

PhPh

HOHOO

OO

N3N3

PhPh

O

PivOPivO

PivOPivO

OPivOPiv

PivOPivO

OS

PivOPivO

PivOPivO

OPivOPiv

PivOPivOPhPh

O

TfOH, THF, –65 °CTfOH, THF, –65 °C

S O

O

HNHN

OO

OO

N3N3

PhPh


CH2Cl2


CH2Cl2


CH3OH


CH3OH

OO

O

OHOH

HOHO

OHOH OHOHOHOH

OHOH NHAcNHAc

S O

O

HNHN

Combinatorial Synthesis of a Disaccharide LibraryCombinatorial Synthesis of a Disaccharide Library

H2NNH2H2NNH2

DMFDMF

AcO OO

O

N3

SAr

Ph

AcO OO

O

N3SAr

Ph

AcOO

N3SAr

OOPh

AcOO

N3

SArOOPh AcO

ON3

OPMB

OPMB

SAr

AcO OO

O

OPMB

SAr

Ph

OSOPh

PivO

PivO

OPiv

PivO

O

SOPh

PivOPivO

OPiv

OPiv

OSOPh

O

O

OPiv

OPMB

OSOPh

PivOPivO

OPiv

PivO

OO

SOPh

O

O

CH3

N3

O

O SOPhOPiv

PivO

PivOPivO

O SOPhOPiv

H3C

PivON3

O SOPhOPiv

H3C

PivOOPiv

O

SOPh

N3

H3C

OO

O

O

SOPh

OPMBH3C

OO

O

O

PivO

PivO

OPiv

PivO

OSOPhO

PivO

OPiv

PivO

OSOPhPivO

OPiv

PivO

O

O

PivOPivO

OPiv

PivO

Glycosyl donors:

Acylation agents:

Ac2O, iBuCOCl, BuCOCl, PhCOCl, D-Ac-Ala-OH, L-Ac-Ala-OH, MeOCO2Cl

COClCOCl

COCl

O2N

NO2

FI

N CO2HN+ CO2H

O–

S COCl

O OO C NCH3 H3C S Cl

O

O

S C NCH3

OOO

H2C

AcOAcO OO

O

N3N3

SArSAr

PhPh

AcOAcO OO

O

N3N3SArSAr

PhPh

AcOAcOO

N3N3SArSAr

OOPhPh

AcOAcOO

N3N3

SArSArOOPhPh AcOAcO

ON3N3

OPMBOPMB

OPMBOPMB

SArSAr

AcOAcO OO

O

OPMBOPMB

SArSAr

PhPh

OSOPhSOPh

PivOPivO

PivOPivO

OPivOPiv

PivOPivO

O

SOPhSOPh

PivOPivOPivOPivO

OPivOPiv

OPivOPiv

OSOPhSOPh

O

O

OPivOPiv

OPMBOPMB

OSOPhSOPh

PivOPivOPivOPivO

OPivOPiv

PivOPivO

OO

SOPhSOPh

O

O

CH3CH3

N3N3

O

O SOPhSOPhOPivOPiv

PivOPivO

PivOPivOPivOPivO

O SOPhSOPhOPivOPiv

H3CH3C

PivOPivON3N3

O SOPhSOPhOPivOPiv

H3CH3C

PivOPivOOPivOPiv

O

SOPhSOPh

N3N3

H3CH3C

OO

O

O

SOPhSOPh

OPMBOPMBH3CH3C

OO

O

O

PivOPivO

PivOPivO

OPivOPiv

PivOPivO

OSOPhSOPhO

PivOPivO

OPivOPiv

PivOPivO

OSOPhSOPhPivOPivO

OPivOPiv

PivOPivO

O

O

PivOPivOPivOPivO

OPivOPiv

PivOPivO

Glycosyl donors:Glycosyl donors:

Acylation agents:Acylation agents:

Ac2O, iBuCOCl, BuCOCl, PhCOCl, D-Ac-Ala-OH, L-Ac-Ala-OH, MeOCO2ClAc2O, iBuCOCl, BuCOCl, PhCOCl, D-Ac-Ala-OH, L-Ac-Ala-OH, MeOCO2Cl

COClCOClCOClCOCl

COClCOCl

O2NO2N

NO2NO2

FI

N CO2HCO2HN+N+ CO2HCO2H

O–O–

S COClCOCl

O OO C NCH3NCH3 H3CH3C S ClCl

O

O

S C NCH3NCH3

OOO

H2CH2C

3) Bidirectional Glycosylation Strategy

OHOBnO

BnO

SEt

O

HN

O

O

O

O

acceptor bound

OBnOBnO

BnOO CCl3

NH

BnO

TMSOTf

O

BnOBnO

SEt

O

NHO

O

O

O

OBnOBnO

BnO

BnO

O

O

O

O

OH

O

O

NIS/TMSOTfdonor bound

O

BnOBnO

O

NHO

O

O

O

OBnOBnO

BnO

BnO

O

O

O

O

O

O

O

NaOMe, MeOH

O

BnOBnO

OBnOBnO

BnO

BnO

O

O

O

O

O

O

O

HO

3) Bidirectional Glycosylation Strategy3) Bidirectional Glycosylation Strategy

OHOHOBnOBnO

BnOBnO

SEtSEt

O

HNHN

O

O

O

O

acceptor boundacceptor bound

OBnOBnOBnOBnO

BnOBnOO CCl3CCl3

NHNH

BnOBnO

TMSOTfTMSOTf

O

BnOBnOBnOBnO

SEtSEt

O

NHNHO

O

O

O

OBnOBnOBnOBnO

BnOBnO

BnOBnO

O

O

O

O

OHOH

O

O

NIS/TMSOTfNIS/TMSOTfdonor bounddonor bound

O

BnOBnOBnOBnO

O

NHNHO

O

O

O

OBnOBnOBnOBnO

BnOBnO

BnOBnO

O

O

O

O

O

O

O

NaOMe, MeOHNaOMe, MeOH

O

BnOBnOBnOBnO

OBnOBnOBnOBnO

BnOBnO

BnOBnO

O

O

O

O

O

O

O

HOHO

O

OHOBnO

BnO

SEt

O

HN

O

O

O

O

Generation of a small carbohydrate library........Monomers

OHOBnO

BnO

BnOOMe

O

BnOBnO

OHBnO

OMe

O

BnOBnO

HO OBn

OBn

Couple witheach monomer

OTHPOBnO

BnO

O

O

HN

O

O

O

O

OMe

products obtained asmixture of anomers

1. AcOH/H2O

6 compounds total OSEt

BnO OBn

BnO

OBn

NIS/TMSOTf

OOOBnO

BnO

O

O

OMe

O

BnO OBn

BnO

OBn

1. NaOMe

2. H2/Pd

OOOHO

HO

O

OH

OMe

O

HO OBn

HO

OH

OBn

OBn

OH

Boons and Zhu in "Solid Support Oligosaccharide Synthesis andCombinatorial Carbohydrate Libraries," P. Seeburger, ed.; WileyInterscience, New York, pp. 201-211.

O

OHOHOBnOBnO

BnOBnO

SEtSEt

O

HNHN

O

O

O

O

Generation of a small carbohydrate library........Generation of a small carbohydrate library........MonomersMonomers

OHOHOBnOBnO

BnOBnO

BnOBnOOMeOMe

O

BnOBnOBnOBnO

OHOHBnOBnO

OMeOMe

O

BnOBnOBnOBnO

HOHO OBnOBn

OBnOBn



OTHPOTHPOBnOBnO

BnOBnO

O

O

HNHN

O

O

O

O

OMeOMe

products obtained asmixture of anomersproducts obtained asmixture of anomers

1. AcOH/H2O1. AcOH/H2O

6 compounds total6 compounds total OSEtSEt

BnOBnO OBnOBn

BnOBnO

OBnOBn

NIS/TMSOTfNIS/TMSOTf

OOOBnOBnO

BnOBnO

O

O

OMeOMe

O

BnOBnO OBnOBn

BnOBnO

OBnOBn

1. NaOMe1. NaOMe

2. H2/Pd2. H2/Pd

OOOHOHO

HOHO

O

OHOH

OMeOMe

O

HOHO OBnOBn

HOHO

OHOH

OBnOBn

OBnOBn

OHOH



NH2

Solid-Phase Chemical/Enzymatic Oligosaccharide Synthesis

OO

OSi

NH2

controlled-pore glass

(Gly)6NHBocOO

OSi

HN

HN

O

O

OHN

O

NH

O

NHBoc

O

NHO

OH

NHAcHOHO

HN

O

O

OHN

O

NH

O

NHBoc

Bn O

NHO

NHAcHOOO

OHHO

OH OHOH

β-1,4-galactosyltransferase

PO

P

O–O

O–O

ON

OHHO

NH

O

OOOO

OHHO

OH OH

UDP-Gal

Wong, C.-H., et al. (1994). Solid-Phase Chemical Enzymatic Synthesis ofGlycopeptides and Oligosaccharides. Journal of the American ChemicalSociety 116, 1135 - 1136.

α-2,3-sialyltransferase

PO

O–O

ON

OHHO

N

NH2

OO

HO2C

AcHNHO

HHO

OHHO

CMP-NeuAc

55%

NH2NH2

Solid-Phase Chemical/Enzymatic Oligosaccharide SynthesisSolid-Phase Chemical/Enzymatic Oligosaccharide Synthesis

OO

OSiSi

NH2NH2

controlled-pore glasscontrolled-pore glass

(Gly)6NHBoc(Gly)6NHBocOO

OSiSi

HNHN

HNHN

O

O

OHNHN

O

NHNH

O

NHBocNHBoc

O

NHNHO

OHOH

NHAcNHAcHOHOHOHO

HNHN

O

O

OHNHN

O

NHNH

O

NHBocNHBoc

BnBn O

NHNHO

NHAcNHAcHOHOOO

OHOHHOHO

OHOH OHOHOHOH

β-1,4-galactosyltransferaseβ-1,4-galactosyltransferase

PO

P

O–O–O

O–O–O

ON

OHOHHOHO

NHNH

O

OOOO

OHOHHOHO

OHOH OHOH

UDP-GalUDP-Gal



α-2,3-sialyltransferaseα-2,3-sialyltransferase

PO

O–O–O

ON

OHOHHOHO

N

NH2NH2

OO

HO2CHO2C

AcHNAcHNHOHO

HHOHO

OHOHHOHO

CMP-NeuAcCMP-NeuAc

55%55%

HN

O

O

HN

O

NH

NHBoc

Bn O

NHO

NHAcHOOO

OHO

OH OHOH

HO2C

AcHNHO

HHO

OHHO

α-chymotrypsin

HO

OHN

O

NH

O

NHBoc

Bn O

NHO

NHAcHOOO

OHO

OH OHOH

HO2C

AcHNHO

HHO

OHHO

OH3C

HO OHOH

α-1,3-fucosyltransferase

GDP-Fucose

HO

OHN

O

NH

O

NHBoc

Bn O

NHO

NHAcOOO

OHO

OH OHOH

HO2C

AcHNHO

HHO

OHHO

65%

>95%

35%+ 20% des-NeuAc

+45% starting material

HNHN

O

O

HNHN

O

NHNH

NHBocNHBoc

BnBn O

NHNHO

NHAcNHAcHOHOOO

OHOHO

OHOH OHOHOHOH

HO2CHO2C

AcHNAcHNHOHO

HHOHO

OHOHHOHO

α-chymotrypsinα-chymotrypsin

HOHO

OHNHN

O

NHNH

O

NHBocNHBoc

BnBn O

NHNHO

NHAcNHAcHOHOOO

OHOHO

OHOH OHOHOHOH

HO2CHO2C

AcHNAcHNHOHO

HHOHO

OHOHHOHO

OH3CH3C

HOHO OHOHOHOH

α-1,3-fucosyltransferaseα-1,3-fucosyltransferase

GDP-FucoseGDP-Fucose

HOHO

OHNHN

O

NHNH

O

NHBocNHBoc

BnBn O

NHNHO

NHAcNHAcOOO

OHOHO

OHOH OHOHOHOH

HO2CHO2C

AcHNAcHNHOHO

HHOHO

OHOHHOHO

65%65%

>95%>95%

35%+ 20% des-NeuAc


35%+ 20% des-NeuAc


7. Special topic: Immobilization of catalysts

RR

R

P P

PP

P

P

CC

NON-MISCIBLELIQUID PHASES

BIPHASIC SYSTEMS EASIER RECYCLING

CC

R

R

R

RP

P

P

P

P

PP

SEPARATION OF CATALYST?

PURITY OF PRODUCTS

HOMOGENEOUSCATALYST

• Hydrophylic

• Hydrophobic

• Fluorinated

• Ionic liquids

• Supercritical fluids

R

R

R

RP

P

P

P

P

P

PC

C

SOLIDCATALYST

RR

R

P P

PP

P

P

CC

NON-MISCIBLELIQUID PHASES

BIPHASIC SYSTEMS EASIER RECYCLING

CC

R

R

R

RP

P

P

P

P

PP

SEPARATION OF CATALYST?

PURITY OF PRODUCTS

HOMOGENEOUSCATALYST

IMMOBILIZATION METHODS

STRONG INTERACTION WEAK INTERACTION

ML*

ML*

*LM

SUPPORTCOVALENTBOND

ELECTROSTATICINTERACTION SUPPORT

[ML*]+

[ML*]+

[ML*]+

ADSORPTION SUPPORT

[ML*]

[ML*]

[ML*]

[ML*]ENTRAPMENT

TYPES OF SUPPORTS

example

solubilitysolvent

mass transportproblems

separation

number ofanchoring points

linearpolymer

polystyrene (PS)

solubledependent

no

difficult

high

cross-linkedpolymer

PS-DVB (0.5-3%)

swellabledependent

little

filtration

high

highly cross-linkedpolymer

PS-DVB (>5%)

insolubleindependent?

potential

filtration

high

inorganic

silica

insolubleindependent

potential

filtration

high

P X Y C*+ P Z C*

P X Y L*+ P Z L*

M

P X P Precursor

Grafting

Ligand synthesis in solid phase

Polymerisation

R L*(C*)R

IMMOBILISATION BY COVALENT BOND FORMATION(I) ORGANIC POLYMERS

SOLUBLE POLYMER SUPPORTS

HOMOGENEOUSREACTION

Price of membranes

INSOLUBILIZATION OFTHE SUPPORTED CATALYST

ULTRAFILTRATIONSOLUBILIZATION IN

A NON-MISCIBLE PHASE

H2C CH21. Anionic polymerisation

2. CO2

3. Me2SBH3

H(CH2CH2)nCH2OH

NH

COOHO

NH

COOPEO

OCOCHN2

polymeric ligand(PL)

(PL)4Rh2

toluene reflux O

O

Run %yield %ee

1 58 98

3 58 83

7 58 61

RECOVERING BY CENTRIFUGATIONAT ROOM TEMPERATURE

CHANGE OF SOLVENTCHANGE OFTEMPERATURE

IMMOBILISATION OF HYDROGENATION CATALYSTS: POLYMERISATION

CH2CH CH2C

CH3

O0,05 0,85

CH2C

CH3

O

O

O0,10

O

ON

Ph2P

Ph2P

90% e.e.

O

OH

CH2CH

O O

CH2OTsTsOCH2

CH2C

CH3

O

OH

O0,08 0,92

COOH

NHCOMePh

COOH

NHCOMePhMeOH

RH2

TEST REACTION

ACA

CH2CH

O O

CH2PPh2Ph2PCH2

CH2C

CH3

O

OH

O0,08 0,92NaPPh2 CATALYST

[Rh(C2H4)Cl]2

86% e.e.

(homog. 81% e.e.)

reusable in the absence of air

IMMOBILISATION OF HYDROGENATION CATALYSTS: GRAFTING

OO

HN N

O OPS

n

Tentagel (n= 60)Ph2P

PPh2

Rh+(cod)BF4-spacer

PPh2

PPh2

Ru+(cod)

O

HNPS

TEST REACTION

COOMe

O

COOMe

OH

THF/MeOH

R

H2

97% ee(rec. 90% ee)

MeOH: no reaction

EtOH: 90% ee, no reusable

Benzene/MeOH: 97% ee,

reusable once

ACA HYDROGENATION

EXAMPLES OF GRAFTING ONTO POLYMERS: AMINOALCOHOLS

N

OHMe

PS

N

Me

OH

Me Ph

PS

PS N

HO PhPh

N

Ph O

Me Me

OH

R1

R2

P

Merrifield (R1=R2=H): Synthesis in solid phase

up to 69% ee

Barlos (R1=Ph, R2=o-Cl-Ph): Grafting

94% ee

CHOOH

ZnEt2 S

5-10% cat.

TEST REACTION

92% e.e. (S)

80-89% e.e. (R)

96% e.e.

EXAMPLES OF GRAFTING ONTO POLYMERS: Mn(salen)

O

N N

O

Mn

ClOO

OO

P

TEST REACTIONS

M-CPBA, NMO

O

4% catal.-78ºC-rt

P styrene dhnapht

yield %ee yield %ee

MeOPEG 62 57 70 76

NCPS 76 51 69 73

JandaJel 81 51 71 79

Merrifield 61 35 69 78

Me 82 52 75 84

MeOO

OHn

MeO-PEG Ph

OH

n m

NCPS(non-cross-linked PS)

O O

cross-linkerin JandaJel

SYNTHESIS OF THE LIGAND IN SOLID PHASE

OPOH

CHO

tBu

TEST REACTION

M-CPBA, NMO

Ph PhO

Porous PS 61% ee

Gel-type PS 66% ee

Porous polymethacrylate 91% ee

tBu

But

HO

OPOH

tBu

N N

OPOH

tBu

N NH2

tBu

But

O

OPO

tBu

N N

Mn

OAc

POLYMERISATION OF TADDOLS

Catalyst in themain chain

Catalyst in thecross-linking points

TEST REACTION

COR

N O

O O

conv. endo/exo %ee

Ar=Ph 63 87/13 30

Ar=2-napht 92 87/13 56

30 81/19 6

OH

OH

Ar Ar

Ar Ar

O

O

H

2) Ti(OiPr)2Cl2

OH

OH

Ph Ph

O

O

1) styrene/DVBCATALYSTS

[Ru(p-cymene)Cl2]2

[Ir(cod)Cl]2

Support method conv. %ee

TEST REACTION

OTHER CATALYSTS FOR HYDROGEN TRANSFER

Ph

O

Ph

OHiPrOH

KOH

SO2

HN

NH2

Ph

Ph

+Polymerisation

O

NH

P

SO2

HN

NH2

Ph

PhGrafting

PS grafting 88 91

tentagel grafting 9 55

PS polym. 23 84

PS polym. 73 91

OH

OH

O

OM L*

O

OL-M-L*

O

OL*-M-L

IMMOBILISATION BY COVALENT BOND FORMATION (II) INORGANIC SOLIDS

Grafting (ligand or catalyst)

Ligand synthesis in solid phase

“Polymerisation” (sol-gel synthesis)

O

OSi L*-M-L

O

O

OSi L*

O

(RO)3Si L*-M-L

(RO)3Si L*Si(OR)4

Si(OR)4

INORGANIC SUPPORTS FOR COVALENT IMMOBILIZATION

SiOSiO22 quartz

silicaS

• Precipitation (hydrolysis)

• Pyrolysis SiCl4 (vapour)

• Surface area

• Porosity

(size and distribution)

• Silanol density

MESOPOROUS CRYSTALLINE SILICAS

Surfactant(template)

Control of pore size(25-100 Å, narrow distribution)

SiO

O

O

OH SiO

OOH

OHSi

O

O

O

OH

SiO

O

OHisolated geminal

vicinalSi

O

O

O

OSiMe3

"end-capped"

SILANOLGROUPS

GRAFTING THROUGH THE METAL CENTRE

OAl

Et

Cl

Et2AlCl+

(-)-menthol

-50OC

< 15% cat.

CHOCHO

TEST REACTION

+

Enantioselectivity similar to that

obtained with the analogous in

homogeneous phase.

(2 equivalents of menthol are

needed for better selectivities)31% ee

OAl

O

Cl

SILICA

POSSIBILITIES FOR SILICA FUNCTIONALIZATION

OH

OH+ (RO)3Si-R'

O

OSi

OR

R' functionalizedgroup

-(CH2)3-NHR

-(CH2)3-SH-(CH2)3-X (Cl, Br, I)

-(CH2)11-Br

-(CH2)3-NCO

-(CH2)n-CH=CH2 (0 ≤ n ≤ 6)-(CH2)2-Ph

NH2

CH2Cl

SO2Cl

O O

AlkylationImine or amide formation

Reaction with amines or alcohols(formation of secondary amines, ethers, ureas, carbamates, sulfonamides)

AlkylationRadical addition

Radical addition

Aromatic electrophilic substitution

HYDROGENATION CATALYSTS ON SILICA

COOMe

NHCOCH3Ph

COOMe

NHCOCH3Ph

SH2

TEST REACTION S D loading conv (min) % e.e.(m2/g) (nm) (μmol/m2)

310 14 0.18-0.63 100 (20-30) 91.7-93.5

100 (14-23) 92.1-94.5

370 10 0.22 99 (26) 92.5

No interactions between cationic species

(EtO)3SiHN N

O

PPh2

PPh2

a) silica/toluene

b) [Rh(cod)2]BF4

Deactivation with small pores (pore blocking?)

590 4.4 0.31 99 (90) 89.3

33 (114) 86.8

OSi

HN N

O

Ph2P

PPh2

Rh+(cod)BF4-O OEt

DIHYDROXYLATION CATALYSTS ON SILICA

PhPh

PhPh

OH

OH

TEST REACTION

K3[Fe(CN)6]/K2CO3

tBuOH/water

+ OsO4 Loss of Os

Problem of toxicity

77-88% yield99% e.e.

OSi S

O OMe N

N

MeO

OSiS

OMeON

N

OMe

O ONN

OSi

O OMe

O

N

N

NN

OSi

O OMe

O

NN

MeO

O

NN

MeO

O

EPOXIDATION CATALYSTS ON SILICA

Synthesis of the ligandin solid phase

Ph

MCPBA

NMO Ph

O

TEST REACTION

R R

(-78ºC)

R cat. time conv (%) % e.e.

H homog. 45 min 97 84

heterog. 4 h 92 89

Me homog. 45 min 81 43

heterog. 4 h 74 56

O

N N

Mn

O tBu

PhPh

N

Si OMe

O O

Cl

MCM-41

IMMOBILIZATION WITH FORMATION OF THE SUPPORT

O OH

iPrOH

KOHS

TEST REACTION

Low surface area(3-11 m2g-1)

x = 0-3

x time (d) conv (%) % e.e.

homog. 5 95 26

0 5 75 58

1 7 60 10

3 8 20 15

NH

NH

Si(OEt)3

Rh(cod)Cl

Si(OEt)3

NH

NH

Si

Rh(cod)Cl

Si

OO

O

O

OO SILICA

SILICA

x Si(OEt)4

H2O

Npht-COCH33 7 30 98

IMMOBILIZATION BY ELECTROSTATIC INTERACTION

M++

SOLID SOLUTION

+

CATIONIC

EXCHANGE

X-

X-L*L*

L

L

M+ L*L*

L

L

SOLID SOLUTION

M+M

CHARGE SITUATION

G+

metal ligand

H2

M L*L*

L

L

+

neutral

H+

TYPES OF INORGANIC SUPPORTS

CLAYS

SiO4

tetrahedra

AlO6

octahedra

~ 10 Å

+ + +

- -

-

TOT

exchangeablecations

HYDROTALCITES

[Mg0.75Al0.25(OH)2](CO3)0.125

Interlamellar space

Isomorphous substitutions: Al

exchangeableanions - -

octahedrallayer

+

+

MESOPOROUSCRYSTALLINE

SILICAS

MICROPOROUSZEOLITES

Pores: 25-100 Å

Pores: 4-10 Å

Supermicropores bypartial destruction

of the structure

HYBRID MATERIALS

TYPES OF ORGANIC SUPPORTS

POLYMERS

n m

SO3Na

p

O O O

Si

SILICA

SO3Na

(RO)3Si X

+

Silica

1) Grafting

2) Transformation(X SO3Na)

Grafted organic groups

+

Silica

synthesis

CF2CF2

CF2

SO3H CF2CF2

CF2SO3H

CF2CF2

CF2SO3H

CF2CF2

CF2SO3H

nafion-silicananocomposite

Si(OR)4

Composites

Variations:

• Main chain: -(CF2)n-

• Cross-linking: nature and degree

• Charged group: -COONa, -NR3

+

[L*-M]+X- + support [L*-M]+ + Na+X-supportNa+

L* + M+X- + support supportL* + + Na+X-Na+ M+

THE EXCHANGE PROCESS

IMPORTANCEOF SOLVENT

• Complex and leaving salt in solution

• Possible coordination to M: deplacement of chiral ligand

• Compatible with support: swelling

HYDROGENATION WITH CLAY-IMMOBILIZED CATALYSTS

COOH

NHCOCH3

COOH

NHCOCH3

H2

EtOHR

R

N

N

PPh2

Ph

PPh2

Ph

Rh(cod)

+

HECTORITE R = H70% e.e.

100% conv (1-6 h)5 cycles

PPh2

PPh2

NH2

H Me

Fe Rh(cod)

HECTORITE

+

27.

2 A

COOBu

COOBu

COOBu

COOBu

H2

R = Phhectorite 49% e.e.nontronite 0% e.e.

EFFECT OFSUPPORT

EFFECT OFSOLVENT ANDIMMOBILIZATION

% e.e. MeOH EtOH iPrOHHomog.: 15 32 56Heterog.: 64 88 84

IMMOBILIZATION ON CATIONIC SUPPORTS

HYDROTALCITE AS SUPPORT

P

Ru

PCl+

SO3-

Cl-

SO3-

SO3-

SO3-

Big size of the complex

Exchange on the externalsurface of the hydrotalcite

COOMe

COOMe

COOMe

COOMe

48% e.e.

OH OH

100% e.e.

H2

H2

Unclear points:• Need for a MgAl hydrotalcite

• Possibility of reuse

IMMOBILISATION WITHOUT LIGAND-SUPPORT BOND

• Adsorption on the surface

Hydrophylic or hydrophobic interactions

Supported liquid phase

• Entrapment into the pore system

“Ship-in-a-bottle” method

Entrapment between polymer chains

IMMOBILIZATION BY ADSORPTION

O O O

H HH

O O OS

CF3

SILICA

P

P

Rh(cod) COOCH3

NHCOCH3

COOCH3

NHCOCH3

99% e.e.

H2

hexane

HYDROGENBOND

HYDROPHOBICINTERACTION

O

SIL

ICA

O 12

O O12

NPPh2

PPh2

Rh(COD)BF4

tBuCOCOOCH3

NHCOCH3

COOCH3

NHCOCH3

93% e.e.

H2

waterPh

Ph

Glass

Organic

P

PRu

SO3Na

SO3Na

SO3Na

SO3Na

2Cl

H2O

H2O

Glass

OrganicPhase

Porouscatalystparticle

SUPPORTED LIQUID PHASE

MeO

COOH

MeO

COOHH2

(S)-naproxen

Hydrophilic phase: ethyleneglycol

Hydrophobic phase: CHCl3/cyclohexane (1:1)

Results: tof 24 h-1, 88% e.e. (r.t.)

96% e.e. (3ºC)

ENTRAPMENT INTO ZEOLITES “ship-in-a-bottle” synthesis

O

N NMn

OR2

R1 R1

R2

HH

+ Complex is toolarge to leaveAnd to be accommodated?

Mn2+

(zeolite supercage)

channel

Ligand componentsare small enough toenter the zeolitechannels

OH

CHO

R2

R1H2N NH2

HH

ENTRAPMENT INTO MEMBRANES

SiMe

Me

O SiMe

Men "curing"

+

Si

OSiMe2H

HMe2SiO OSiMe2H

OSiMe2H

P

P

Rh(cod)

OTf

P

P

Rh(cod)

OTf

COOCH3

OCOOMe

OH

90-93% e.e.

H2

solvent swelling solubility leachingPhCl 173 21 100Et2O 240 7 90acetone 15 90 62MeOH 2 162 54heptane 235 0.3 12

Entrapment of Mn(salen)

cross-linkedpolysiloxane(membraneform)

"SWELLING"

SOLVENTEFFECT

CONCLUSIONS

COVALENT BOND

ELECTROSTATIC

ADSORPTION

ENTRAPMENT

Ligand retention

Versatility

Simplicity

Without ligandmodification

Ligand modification(effect on e.e.)

Metal leaching(possible )

Ionic character

Ligand leaching(possible )

Leaching andsolubility

Complex size

Swelling and leaching

pro contra

References

• Chiral Catalyst Immobilization and Recycling; D. E. De Vos, I. F. J. Vankelecom, P. A. Jacobs, Eds.; Wiley-

VCH: Weinheim, 2000.

• Comprehensive Asymmetric Catalysis; E. N. Jacobsen, A. Pfaltz, H. Yamamoto, Eds.; Springer-Verlag:

Berlin-Heidelberg, 1999; chapters 37 and 38.

• D. C. Sherrington, P. Hodge. Synthesis and Separations using Functional Polymers; Wiley: New York, 1988.

• W. T. Ford. Polymeric Reagents and Catalysts; ACS Symposium Series 308, American Chemical Society:

Washington, 1986.

• H.-U. Blaser, Tetrahedron: Asymmetry 1991, 3, 843.

• S. J. Shuttleworth, S. M. Allin, P. K. Sharma, Synthesis 1997, 1217.

• L. Pu, Tetrahedron: Asymmetry 1998, 9, 1457.

• L. Canali, D. C. Sherrington, Chem. Soc. Rev. 1999, 28, 85.

• Y. R. de Miguel, J. Chem. Soc. Perkin Trans. 1 2000, 4213.

• S. J. Shuttleworth, S. M. Allin, R. D. Wilson, Synthesis 2000, 1035.

• Y. R. de Miguel, E. Brulé, R. G. Margue, J. Chem. Soc. Perkin Trans. 1 2001, 3085.

• B. Clapham, T. S. Reger, K. D. Janda, Tetrahedron 2001, 57, 4637.

REVIEWS

BOOKS

II. Liquid phase synthesis

Dickerson, Tobin J.; Reed, Neal N.; Janda, Kim D. Chem. Rev. 2002, 102, 3325.

Polyglycerol

Haag, R. et. al. J. Comb. Chem., 2002, 4, 112; Haag, R. Chem. Eur. J., 2001, 7, 327

Soluble Polymers

Janda, K. D. Chem. Rev., 1997, 97, 489-509.Janda, K. D. Chem. Rev., 2002, ASAP.

LPS supported synthesis of Prostaglandins

Janda, K. D. JACS., 1997, 119, 8724-8725.

PEG-Supported Sulfoxide for Swern Oxidations

Harris, J. M, etc. J. Org. Chem., 1998, 63, 2407.

Chemical Tagging

Fluorous Method: A solution phase method

Luo, Z.; Zhang, Q.; Oderaotoshi, Y.; Curran, D. P. Science 2001, 291, 1766-1769.

Starter Library of Mappicine Analogs

Luo, Z.; Zhang, Q.; Oderaotoshi, Y.; Curran, D. P. Science 2001, 291, 1766-1769.

Automated High Throughput Purification

www.biotage.com

Wilcox’s Precipitons

Bosanac, T.; Yang, J.; Wilcox, C. S. Angew. Chem. Int. Ed. 2001, 40, 1875-1879.Bosanac, T.; Wilcox, C. S. J. Am. Chem. Soc. 2002, 124, 4194-4195.

ROM Polymerization

1st-G: Schwab, P.; Grubbs, R. H.; Ziller, J. W. J. Am. Chem. Soc. 1996, 118, 100-110.2nd-G Scholl, M.; Ding, S.; Lee, C. W.; Grubbs, R. H. Org. Lett. 1999, 1, 953-956.

Features of Phase Trafficking via ROMP

Impurity Trapping: Chromatography Free Mitsunobu Reaction

Barrett, A. G. M., et. al. Org. Lett. 2000, 2, 2999.Barrett, A. G. M. Chem. Bev. 2002, ASAP.

Synthesis of ROMPgel Activated Esters

Barrett, A. G. M., et. al. Org. Lett. 2000, 2, 261-264.

Acylation of Amines Using ROMPgel Supp. Esters


Polymer supported Tosmic Reagent


NC

Polymer supported Tosmic Reagent


Sequestration of Excess Amine


Bolm ROM-Polymer Catalyst

Bolm, C.; Dinter, C. L.; Seger, A.; Hocker, H.; Brozio, J. J. Org. Chem. 1999, 64, 5730-5731.

Radical Reactions on Soluble ROMP Supports

OO

OO Br

Ph

Br

Ph

Bu3Sn

OO

OO

PhPh

n

AIBN, PhH

80oC

n

Precipitate from tin saltswith cold MeOH

Br

OR

O

Bu3SnHZnCl2, Et3B, O2

N

O

O

H

H

O

O

OH

H

OR

O

n

CH2Cl2, -78oC

R =

Precipitate from tin saltswith cold MeOH

>90:1 de

Enholm, E. J.; Gallagher, M. E. Org. Lett. 2001, 3, 3397-3399.

Enholm, E. J.; Cottone, J. S. Org. Lett. 2001, 3, 3959-3962.

Capture-ROMP-Release: Synthesis of Amino Acids

Mukherjee, S.; Poon, K. W. C.; Flynn, D. L; Hanson, P. R., Tetrahedron Lett. 2003, 44, 7187-7190.

Reviews on polymer-bound reagents

Polymer-supported organic catalystsBenaglia, M.; Puglisi, A.; Cozzi, F. Chem. Rev. 2003, 103, 3401

Recent advances in asymmetric C-C- and C-heteroatom bond forming reactions using polymer-bound catalystsBräse, S.; Lauterwasser, F.; Ziegert, R. E. Adv. Synth. Catal. 2003, 345, 869

Whole issue dedicated to polymer-bound reagentsChem. Rev. 2002, 102, No. 10

*New tools and concepts for modern organic synthesisLey, S. V.; Baxendale, I. R. Nature Reviews: Drug Discovery 2002, 1, 573

Functionalized polymers – emerging versatile tools for solution-phase chemistry and automated parallel synthesisKirschning, A.; Monenschein, H.; Wittenberg, R. Angew. Chem. Int. Ed. Engl. 2001, 40, 650

Multi-step organic synthesis using solid-supported reagents and scavengers: a new paradigm in chemical library generationLey, S.V. et al. J. Chem. Soc., Perkin Trans. 1 2000, 3815

Solid-supported reagents in organic synthesisDrewry, D. H.; Coe, D. M.; Poon, S. Med. Res. Rev. 1999, 19, 97

Solution-phase chemical library synthesis using polymer-assisted purification techniquesParlow, J. J.; Devraj, R. V.; South, M. S. Curr. Opin. in Chem. Biol. 1999, 3, 320

Functionalized polymers: Recent developments and new applications in synthetic organic chemistryShuttleworth, S. J.; Allin, S. M.; Sharma, P. K. Synthesis 1997, 1219.


Conventional synthesis

Solid phase synthesis

Synthesis using a solid-supported reagent

A + BRe agent

A B

A + B A BRe agent

+ BReagent

A A B


Different types of polymer-bound reagents

Reagents

Scavengers

Quenching reagents

Capture-and-release reagents

Reage nt

productsubstra te

+

productsubstrates

+Scav eng er

product

Scav eng er+

Capturing rea gen t

Capturing rea gen tRelease

product

Attaching reagents to the solid phase instead of substrates provides similar advantages:

- Ease of purification allows the use of excess reagents

Excess reagents can be removed by use of a solid phase-bound “scavenger” that reacts with or binds the excess reagent

Solid Phase Reagent and Scavenger Resins

Starting Material

Reagent

Product

Reagent+

Clean Product

Filter

Starting Material

Excess Reagent

Product

Reagent+

Clean Product

Scavenger1)

2) Filter

+

Scavenger

Reagent

Advantages

Easy workup / can be automated

Toxic or volatile reagents can be immobilized

Two incompatible reagents can be used at the same time (’wolf and lamb’)

Excess reagent can be used

Compared to solution phase chemistry

Advantages

Compared to solid phase chemistry

Easier to develop chemistry

Easier to analyze intermediates (solution)

Convergent synthesis possible

A B

C D

E

Disadvantages

Slower reaction in some cases

Leaching of metal

More expensive

Solid supports

Polystyrene

Other organic polymers (polyamides etc.)

Soluble polymeric supports (PEG, dendrimers)

Silica

Zeolites

Glass

Graphite

Cellulose

Polystyrene

Microporous polystyrene (1-4% cross-linked)

Macroporous polystyrene (30-50% cross-linked)

Hybrids (PS/PEG)

Soluble polystyrene

Plugs of microporous polystyrene

OO

OHn

How are the reagents/scavengers attached to the resin?

Covalent binding by:

- reaction with a derivatized resin

- co-polymerization of the reagent with styrene and divinylbenzene

Forming an ion-pair

Entrapment, reagent enclosed in a polystyrene network

NM e3

Cl

NaCNNM e3

CN

PPh2

+ +Functionalizedpolymer

ClLiPP h2

PPh2

Polymer-Bound Reagents

Reagent

productsubstrate

Some examples:

Oxidation

Reduction

Nucleophilic reactions

Carbon-carbon bond formation

Amide bond formation

Resin-Supported Reagents

Review: Ley, S. V. et al. J. Chem. Soc., Perkin Trans. 1 2000, 3815-4195.

Scavenger Resins

Reagents for Oxidation

O

NO

X

Ph 2P Co PP h3

Cl

ClCrO 3SiO2

KMnO4SiO2

2

Cr2O72-

NMe3

NMe3 IO4

N OsO4

NMe3 RuO 4


PSP = polymer supported perruthenate

NMe3 RuO4NMe3 ClKRuO 4

ultrasound PSP

OH

PSP, O2

75 - 85 oC

O

H

> 99%

H15C7 OHH15C7 O

H83 %

toluene

as above

Hinzen, B., Lenz, R., Ley, S. V. Synthesis, 1998, 977

C OH C O

Polymer-bound sulfoxide for Swern oxidation

OH

O

SDMAP, DIC O

O

SHO t-BuOOHO

SO

O

H+

OHOPh

OH

sulfoxide

(COCl)2, Et3N

OOPh

O

as above

H

71 %

82 %

Cole, Stock, Kappel Bioorg. Med. Chem. Lett. 2002, 12, 1791

Liu, Y.; Vederas, J. C. J. Org. Chem. 1996, 61, 7856

Reagents for Oxidation C OH C O

Poly(vinylpyridinium dichromate)

NN N N

CrO3

N

+

cross-linkingagent

n

Cr2O72-

n

Fréchet, J. M. J.; Darling, P.; Farrall, M. J. J. Org. Chem. 1981, 46, 1728

OH PDC O

H

OH PDC O

98%

93%

Reagents for Oxidation C OH C O


Dihydroxylation & oxidative cleavage of alkenes

L [OsO 4]

C8H17

N OsO4

Me3NO C8H17

OH

HO

90%

N N

Cl

OsO4

H

O

O

H

65%NaIO4

Nagayama, S.; Endo, M.; Kobayashi, S. J. Org. Chem. 1998, 63, 6094

Cainelli, G.; Contento, M.; Manescalchi, F.; Plessi, L. Synthesis 1989, 45

C CC C

HO OH

C O O C+

Reagents for OxidationC C

O

O

CF3

OO

PS or Tentagel

Epoxidation

COOH

O

SOOH

O

O

N N

N N

O Ru

CO

Reagents for OxidationC C

O

SO4H

O

80%

Epoxidation

SO4HO

80%

Pande, C. S.; Jain, N. Synth. Commun. 1989, 19, 1271

Oxon


Epoxidation & oxidation of amines

oxirane

O

82%

OO

n

NH2oxirane

NO2

83%

N

ON

oxirane

83%

Shiney, A.; Rajan, P. K. ; Sreekumar, K. Polymer International 1996, 41, 377


Asymmetric epoxidation

NMn

N

O OCl

PhPh O

O

Smith, K.; Liu, H.-C. Chem. Commun. 2002, 886

Mn-salen

O

NaOCl, 4-PPNO

37% (94% ee)

4-PPNO = 4-phenylpyridine-N-oxide

Reagents for Reduction

NMe3 BH4 NMe3 (CN)BH3

NH2

NH3

BH4BH4

C O C OH

Pd

N

HDMF

PPh3 BH4

N Zn(BH4)2


H

O

MeOH

OH

100%

NH2

NH3

BH4BH4

C O C OH

Rajasree, K.; Devaky, K. S. J. Appl. Polym. Sci. 2001, 82, 693; Ley, S. V. Schucht, O.; Thomas, A. W.; Murray, P. J. J. Chem. Soc., Perkin Trans 1 1999, 1251

N

O

MeO

MeO

H

BH4NMe3

NiCl2, MeOHN

MeO

MeO

H

OH

88%

Epimaritidine

Reagents for ReductionC O C NH2

NH2

Reductive amination

Scavengers can be used to remove excess aldehyde or excess amine:

N C O

NMe3H

O

H2NH

N HN+

BH4

94%

Yoon, N. M.; Kim, E. G.; Son, H. S., Choi, J. Synth. Commun. 1993, 23, 1595


Dehalogenation

C Br C H

HO

N

NN

N

NH2

O

OHOH

HH

HH

Br

HO

N

NN

N

NH2

O

OHOH

HH

HH

87%

SnH

SnH

Bu Bu

Gerlach, M.; Jordens, F.; Kuhn, H.; Neumann, W. P. Peterseim, M J. Org. Chem. 1991, 56, 5971

Applications

Reagents for oxidation and reduction

NCl

Cl

O

NMe3 BH4

NCl

OH

NCl

ONMe3 RuO4

H

NMe3 OH

CH3NO2 NCl

NO2

OH

NCl

NO2NMe2

CH3SO2Cl

NCl

TBDMSO

TFA

1)

2)

O

NO2NCl

OMs

NO2

NMe3 BH4

NCl

OH

NO2

N

N

CH3SO2Cl

NCl

OMs

NH2

NMe3 BH4

Several steps andpolymer-bound reagents. H

NN Cl

Epibatidine,purity > 90%

Habermann, J.; Ley, S. V.; Scott, J. S. J. Chem. Soc. Perkin Trans. 1 1999, 1253

Amide Formation

RC

OH

O

+H2N

R'

RC

NH

O

R'

NH

S

O O

NN

N

OHHO R1

O

NH

S

O O

NN

N

O R1

O

N R1

O

R2

R3

PyBrOP

R2R3NH

Pop, I. E.; Deprez, B. P.; Tartar, A. L. J. Org. Chem. 1997, 62, 2594

P

NBr

N

NPF6PyBrOP =

’Wolf and Lamb’

Ph Me

O Ph

Ph

O

NO2

PhO

Li

SO3 NH3NH2

1)

2)THF

N

HN

Ph

Ph

Reagents that are incompatible in solution can be used together when bound to a solid phase.

Cohen, B. J.; Kraus, M. A.; Patchornik, A. J. Am. Chem. Soc. 1977, 99, 4165; J. Am. Chem. Soc. 1981, 103, 7620

Polymer-bound Nucleophiles

C X C Nu

NMe3 Nu

Nu = OAr, CN, SAr, N3, NaCO3, NCO, SePh, NO2, NCS

Nucleophilic substitution

Br NMe3 CN CN

72%

Gordon, M.; DePamphilis, M. L.; Griffin, C. E. J. Org. Chem. 1963, 28, 698

Carbon-Carbon Bond Formation

Horner-Wadsworth-EmmonsC O C C

EtOP

O

CN

EtO Cl

H

O

NMe3 OH

Cl

CN

99%

+

O

PEtO

EtO

O

OEt+

H

O NMe3 OH

OEt

O

93%

Soledenko, W.; Kunz, U.; Jas, G.; Kirschning, A. Bioorg. Med. Chem. Lett. 2002, 12, 1833.

PASSflow reactor used:

Metathesis

Cross Metathesis

Ring Closing Metathesis

Ring Opening Metathesis Polymerization

R1 R2

+

catalyst R1

R2

+CM

RCM+

ROMP

[M]

R

R

[M]

R

R

n

Metathesis Catalysts

Schrock type Grubbs type

L

Ru

L

RCl

Cl

L = phosphine or carbene

N

Mo

ORRO Ph

Metathesis reactions are often difficult to purify as the catalyst

(typical 10 – 20 mol%) contaminates the product.

R1 R2

+

R1

R2

+

Metathesis

Mechanism

[M] CH2

[M]

R1

[M]

R1

[M]

R1 R2

R1

R2

R2

R1

Polymer-Bound Metathesis Catalysts

Barrett’s ”boomerang” catalysts

P

PCy3

PC y3

Ru Cl

ClL

PC y3

Ru Cl

ClLPh

+

L1 = PCy3L2 = IMes

CH 2Cl2

reflux+

Ph

NN

IMes

Ahmed, M.; Arnauld, T.; Barrett, A. G. M.; Braddock, D. C.; Procopiou, P. A. Synlett 2000, 1007


Barrett’s ”boomerang” catalysts

PC y3

Ru Cl

ClL

+RuCl

ClL

PC y3

PC y3

Ru Cl

ClL

+

RR

R

unstable

PhPC y3

Ru Cl

ClLPh


Recycling of Barrett’s catalyst

Cycle 1 2 3 4 5 6

% Conversion 100 100 100 88 43 7

CO 2Et

CO 2Et

PC y3

Ru ClCl

IMes CO 2Et

CO 2Et1-octene, PPh3

More Metathesis Catalysts

N N

O

MesMes

Ru

PCy3

Cl

Cl

Ph

Blechert

RuCl

Cl

PCy3

OPEG

Lamaty

PCy2

PCy2

RuClCl

Ph

Ph

Grubbs

Enantioselective Olefin Metathesis

tBu

O

O

tBu

Mo

N

iPr

iPr

Hoveyda / Schrock

O5 mol% catalyst

benzene, RT, 24 h

OH

90% conversion, 95% eemeso compound

Suzuki Reaction

Palladium-catalyzed coupling of an aryl/alkenyl halide with a boronic acid/ester.

X

A

+

AX

or

(RO)2B

B

(RO)2BB

+

or

A

B

or

A

B

or

AB

Pd-cat.

Suzuki Reaction

L2PdR1 X

L2PdR1 OR'

B(OR")2

R2

R'O B(OR")2

R1 X

NaX

R'ONa

R1

L2PdR1 R2

R2

Pd(0)L2

Mechanism

Carbon-Carbon Bond Formation

Suzuki couplingC X C(HO)2B+

Pd cat.

sp2 sp2

C C

Cl

LiPPh2

PPh2

PdLn

Ph2P [Pd]

Pd source: Pd(PPh3)4 PdCl2 Pd(CH3CN)2Cl2 Pd(dba)2 Na2PdCl4

Jang, S. Tetrahedron Lett. 1997, 38, 1793;Fenger, I.; Le Drian, C. Tetrahedron Lett. 1998, 39, 4287

Suzuki Coupling

Bu

OB

O

+Br Hex

{Pd}

NaOEt

benzene80 oC

Bu

Hex

84 %

B(OH)2 NBr

{Pd}

Na2CO3

toluene/water reflux

N+

90 - 95 %

C X C(HO)2B+Pd cat.

sp2 sp2

C C

Suzuki Coupling: Other Catalysts

C X C(HO)2B+Pd cat.

sp2 sp2

C C

Si Si

HN NH

O

OO

S [Pd]

PEG NH

O

PPh2

PdCl

OCy2P [Pd]

Pd(OAc)2 or Pd2(dba)2

UozumiHayashi

Buchwald

Zhang

Stille Coupling

O

O

SnBu 3

Br

R

1) cat. L iCl, NMP

2) NaOMe

MeO

O

R

+Pd cat.

PAr 2

Pd

Ar 2P

PdO

O

O

OPd cat. =

Advantages: Tin reagents are toxic – easier to handle if bound to a solid support.Tin byproducts often contaminate product in solution reactions.

The Pauson-Khand Reaction

+Co 2(CO )8

OR1

R2

R1

R2


On solid phase

O

O

Co 2(CO) 8

HO

benzene80 oC , 6 h

Oesterhydrolysis

Schore, N. E.; Najdi, S. D. J. Am. Chem. Soc. 1990, 112, 441


Mechanism

RS RL

Co2(CO)8

- 2 CO Co(CO)3Co(CO)3

RS

RL- CO

Co(CO)3Co(CO)2

RS

RL

R

Co(CO)3Co(CO)2

RS

RL

R

CO

alkeneinsertion Co(CO)3RS

RL

Co(CO)3

R

CO

CO insertion

Co(CO)3RS

RL

Co(CO)3

O

reductiveelimination

O

R

(CO)3Co(CO)3Co

RLRS -Co2(CO)6

O

R

RLRS


Using polymer-bound cobalt carbonyl

Ph2P

PPh2

Co (CO )3 Co (CO )4

Ph2P Co (CO )3

Co (CO )4

1 2

Ph2P

PPh2

Co (CO )3

Co (CO )3

3

PPh2 + Co 2(CO )8

+

THF, RT

1,4-dioxane

75 oC

Comely, A.C.; Gibson, S. E.; Hales, N. J. Chem. Commun. 2000, 305


Using polymer-bound cobalt carbonyl

TsN TsN O

Et O2C

Et O2C

OEt O2C

Et O 2C

70 oC, THF, 24 h

CO 50 m bar, 3

as above

61%

49%

Ph2P

PPh2

Co(CO)3

Co(CO)3

3


Using polymer-bound promotors

O SM eN

O

O

+

R

Co2(CO)6

+

1 2

1, THF, RT

or 2, DCE, Δ

O

R

H

H

74 - 99% yield

R = Ph, tBu, Me2(OH)C

Kerr, W. J. et al, Chem. Comm. 2000, 1467; 1999, 2551.

References

Reviews on polymer-bound organometallic reagents:

Recent advances in asymmetric C-C and C-heteroatom bond forming reactions using polymer-bound catalysts

Bräse, Lauterwasser, Ziegert Adv. Synth. Catal. 2003, 345, 869-929

Preparation of polymer-supported ligands and metal complexes for use in catalysisLeadbeater, Marco Chem. Rev. 2002, 102, 3217-3273

Recoverable catalysts and reagents using recyclable polystyrene-based supportsMcNamara, Dixon, Bradley Chem. Rev. 2002, 102, 3275-3300

Soluble polymers as scaffolds for recoverable catalysts and reagentsDickerson, Reed, Janda Chem. Rev. 2002, 102, 3325-3344

Functionalized polymers – Emerging versatile tools for solution-phase chemistry and automated parallel synthesis

Kirschning, Monenschein, Wittenberg Angew. Chem. Int. Ed. Engl. 2001, 40, 650-579

Multi-step organic synthesis using solid-supported reagents and scavengers: a new paradigm in chemical library synthesis

Ley et al. J. Chem. Soc., Perkin Trans 1 2000, 3815-4195

Scavengers

+

productsubstrates

+

Scav eng er

product

Scav eng er+

Scavengers

acidic

basic

nucleophilic

electrophilicH

O

N C O

N

CH3

CH3

N

OH

O

S

OH

O

NH2 N

NH2

NH2

Scavengers

Application

NHN

NHCl

NHN

NCl R1

NN

NCl R1

R2

NH2

NMe2

1) R1X

2)

1) R2X

BEMP

2) NH2

N NP

NN

BEM P =

Xu, W.; Mohan, R.; Morrissey, M. M. Bioorg. Med. Chem. Lett. 1998, 8, 1089

Capture and Release

+

productsubstrates

Capturing reagentCapturing reagent

Release

product

+contaminants

Capture and Release

Tamoxifen library

R2R1O

BO

BO

O

B

R2

BO

OOO

R1

XR3

Pd(dppf)Cl2, base

B

R2

OO

R2

R1

R3

R1

R3 R3

regioisomer

R2

R1

R3+

+NH

O

Si

I1)

2) 30% TFA in CH2Cl2

regioisomer+

5 x 5 library

Pt(PPh3)4

Brown, S. D.; Armstrong, R. W. J. Org. Chem. 1997, 62, 7076

Capture and Release

Synthesis of β-amino alcohols

OH O

Cl

NaH

O

O NH2

O

OH

NH

Impurities

OH O

OH

O

NH2

Capture and Release

Synthesis of β-amino alcohols using polymer-bound borane

Hori, M.; Janda, K. D. J. Org. Chem. 1998, 63, 889

OH O

Cl

NaH

O

O NH2

O

O

N

BY2

HCl

O

OH

NH

2) HBY2

1)

OPEG

BH

2

HBY2 =

Capture-Release Alkylation Utilizing Resin-Bound Sulfonyl Chloride

Rueter, J. K.; Nortey, S. O.; Baxter, E. W.; Leo, G. C.; Reitz, A. B. Tetrahedron Lett. 1998, 39, 975-978.

Capture Activation-Release:Solid-Supported DCT for Amide Synthesis

Masala, S.; Taddei, M. Org. Lett. 1999, 1, 1355-1357.

An Example of Solid Phase Reagents and Scavengers

Ley SV et al. J. Chem. Soc. Perkins. Trans. I 1999, 63, 6625.

OH

MeO

MeO

HONMe3

RuO4

NMe3

BH4

Tf2O,

N NMeO

MeO

NTf

HO

98 % 3 steps

O

MeO

MeO

H NH2

MeO

MeO

NH

HO

An extremely efficient three step reductive amination and triflation is accomplished by the use of solid phase reagents and scavengers

Application: Sildenafil (Viagra™)

HN

N

NN

O

S

OE t

NO

O

N

Sildenafil (ViagraTM)

OH

ON

N

O

S

OE t

NO

O

N

H2N

H2N

Pr

Pr

Pr =

+

1 2

Baxendale, I. R.; Ley, S. V. Bioorg. Med Chem. Lett. 2000, 10, 1983

Sildenafil, building block 1

OH

OS

OEt

NO

O

N

NHN

EtN(i- Pr)2

1)

2) Et2SO4OH

OS

OH

ClO

O

crude 1

Sildenafil, building block 2

Pr NNH

Pr O

H

NH 2NH Me EtOBr

O

N NPNN

NH 2

NM e3 CN+

cat. H+

Pr NN

O

OEt

PrHN

N

O

OEt

CNNC O

MnO2Pr NN

O

OEt

CN

BEMP

BEMP =

BEMP1)

2) NH3/MeOH

N N

NH 2

Pr NH 2

O

2

Sildenafil (Viagra™)

NN

N

HO

HOBt =PyBrOPN

PN N

BrPF6

=

OH

OS

OEt

N O

O

Ncrude 1

HOBt

PyBrOP NN

N

O

OS

OEt

N O

O

N

2

NCO

OS

OEt

N O

O

N NN

O

HN

PrNH2

HN

N

NN

O

S

OEt

N O

O

N

PrEtOH/NaOEt

MW 10 min/120 oC

Sildenafil

Natural Products via Supported Reagents

Baxendale, I. R.; Ley, S. V.; Piutti, C. Angew. Chem., Int. Ed. 2002, 41, 2194-2197Baxendale, I. R.; Brusotti, G.; Matsuoka, M.; Ley, S. V. J. Chem. Soc., Perkin Trans. 1 2002, 143-154Baxendale, I. R.; Lee, A.-L.; Ley, S. V. Synlett 2001, 1482-1484Habermann, J.; Ley, S. V.; Scott, J. S. J. Chem. Soc., Perkin Trans. 1 1999, 1253-1255Ley, S. V.; Schucht, O.; Thomas, A. W.; Murray, P. J. J. Chem. Soc., Perkin Trans. 1 1999, 1251-1252.

Epothilone

O

S

N

O

OH

O

O

H

OH

For a total synthesis of epothilone using polymer-bound reagents, see:

Storer, R. I.; Takemoto, T.; Jackson, P. S.; Ley, S. V. Angew. Chem. Int. Ed.2003, 42, 2521

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