stereoisomer descriptor. stereoisomer enantiomer enantiomer diastereomer diastereomer erythro, threo...

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Stereoisom Stereoisom er er Descriptor Descriptor

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Page 1: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer

StereoisomerStereoisomer

DescriptorDescriptor

Page 2: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer

StereoisomerStereoisomer

EnantiomerEnantiomer DiastereomerDiastereomer Erythro, threo Erythro, threo Meso CompoundMeso Compound EpimerEpimer ChiralChiral Molecules With No Chiral Molecules With No Chiral

CentersCenters

Page 3: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer

DefinitionsDefinitions StereoisomersStereoisomers – compounds with the – compounds with the

same connectivity, different arrangement same connectivity, different arrangement in in spacespace

EnantiomersEnantiomers – stereoisomers that are – stereoisomers that are non-superimposible mirror images; only non-superimposible mirror images; only properties that differ are direction (+ or -) properties that differ are direction (+ or -) of optical rotationof optical rotation

DiastereomersDiastereomers – stereoisomers that are – stereoisomers that are not mirror images; different compounds not mirror images; different compounds with different physical propertieswith different physical properties

Page 4: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer

enantiomerenantiomer

Page 5: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer

Erythro dan threoErythro dan threo

Page 6: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer

Diastereomer:Diastereomer:Stereoisomer yang bukan Stereoisomer yang bukan

pasangan enantiomerpasangan enantiomer

1 dan 2 enantiomer3 dan 4 juga enantiomer

Diastereomer: 1-3; 1-4; 2-3 dan 2-4

Page 7: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer

Epimers:Epimers:distereomer yang berbeda hanya distereomer yang berbeda hanya

pada satu pusat kiral sajapada satu pusat kiral saja

OH

OH

OH

OH

OH

OH OH

OH

OH

OH

OH

OH

Page 8: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer

Senyawa mesoSenyawa meso

Page 9: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer
Page 10: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer
Page 11: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer

ChiralChiral Molecules With Molecules With No Chiral CentersNo Chiral Centers

Allenes can be ChiralAllenes can be Chiral

C C C

H

CH3

C CClHC

CH3

H

ClH

Page 12: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer

Mycomycin, an antibioticMycomycin, an antibiotic

C C C

H

CH=CHCH=CHCH2CO2HCCCCHH

Nocardia acidophilus []D = -130o

PPh2

PPh2

PPh2

PPh2

(S)-BINAP (R)-BINAP

Page 13: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer
Page 14: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer
Page 15: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer

Specifying Configuration (Chirality); Cahn-Ingold-Prelog Notation

Specifies the "configuration" at each chiral center, equivalent to "cis-" and "trans-" etc.

Abbreviated rules Assign priorities to groups attached to chiral

center according to atomic # (same as Z/E rules) Compare 2nd, 3rd etc. atom from center as

necessary, look for first point of difference Multiple bonds "add up" Determine direction of rotation 1 > 2 > 3 looking

with #4 group pointing "away"

Page 16: Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer

Prioritize Using Cahn-Ingold-Prelog Prioritize Using Cahn-Ingold-Prelog RulesRules

Look at atoms directly attached to chirality center a) higher atomic number = higher priority b) heavier isotopes = higher priority

If no difference at first attached atom, move along the chain until the first point of difference.

Multiple-bonded atoms are equivalent to the same number of single-bonded atoms.