synthesis and structure of hypervalent iodine compounds
TRANSCRIPT
Research - Dr. Justik’s Group
Synthesis and Structure of Hypervalent Iodine Compounds
Hypervalent Iodine Compounds
The concept “hypervalent iodine” refers to the unique bonding interaction in iodine(III) and (V) compounds:
Hypervalent Iodine Compounds
Hypervalent iodine oxidants were the original “green” reagents replacing many toxic metals (lead and thallium) in important synthetic transformations:
R1
R2
PhI(OH)OTs
O
R1
R2
n n95% MeOH, RT
+ +
I
+ TsOH
R1
R2
O
R1
R2
n n
+Tl(NO3)3 + TlNO3 + 2 HNO3MeOH, RT
Resaerch InterestsSynthesis and
Reactivity
Improvement of “green” synthetic methodology using hypervalent iodine
Exploration of hetereocyclic syntheses
Preparation of novel iodinanes of interest from an intellectual curiosity or synthetic challenge aspect
Structure
In collaboration with Dr. John Protasiewicz at Case Western Reserve University explore new iodinanes using X-ray crystallography
Characterize novel iodinanes of interest from an intellectual curiosity or synthetic challenge aspect
Hydroxy(tosyloxy)iodobenzene“Koser’s Reagent”
HTIB
A mild and useful oxidant that
mimics elemental bromine
MW 392.22 g/mol
1H-1-hydroxy-5-methyl-1,2,3-benziodoxathiole 3,3-Dioxide
HMBI
A compact heterocyclic equivalent of HTIB
MW 314.10 g/mol
I OHO S
O
O
I
O
S
O
O
OH
Synthesis with Hypervalent Iodine
Synthesis with Hypervalent Iodine
Improving “green” methods with HMBI - MWJ
R1
R2
PhI(OH)OTs
O
R1
R2
n n95% MeOH, RT
+ +
I
+ TsOH
R1
R2
O
R1
R2
n n95% MeOH, RT
+ +S
OHI
O OS
OI
O O
OH
recover, recycle, reuse
HMBI
Synthesis with Hypervalent Iodine
Michelle Borkovec, ‘06
Alyssa Zimmerman, ‘08
Amanda Dechant/Michael Hughes/Heather Sopher ‘09
O
OH
HMBI
MeOH, reflux 20 hrO
O
R'
R R R'
an Isoflavone
NH2
O
HMBI
CH3CN, refluxR R
NH3
reduced HMBI
NaOAc, Ac2OHN
OR
IO
SO
O
OH
O
+H2O
O
OH
-hydroxyketone
+I
OHSO
O
Synthesis with Hypervalent Iodine
Heterocyclic Synthesis
R C C I Ph
Nu:
C C I PhNu
R
C CNu
R
H+
C CI PhNu
R H
- PhI
1,2-rearrangement
C CR Nu
NuR
1,5-insertion
Synthesis with Hypervalent Iodine
Heterocyclic Synthesis (Melanie Knowlton ’10, Rachael Carmichael ‘12)
C C I C C IO
C CO
O
O CCH
1,5-insertion-aryl C-H
O3S O3S
[Red I]
not observed
C
O
CH
1,5-insertion-alkyl C-H
Synthesis with Hypervalent Iodine
Attempted Heterocyclic Synthesis – (Heather Sopher ‘09, Samantha Kristufek ’11?)
Ph I C C Ph
N O
N OPh
OTs
OTs
???
Synthesis with Hypervalent Iodine
Attempted Heterocyclic Synthesis – (Heather Sopher ‘09, Samantha Kristufek ’11)
Ph I C C Ph
N O
NO Ph
OTs
OTs
OTs
I
PhH
Synthesis with Hypervalent Iodine
Heterocyclic Synthesis
R C C I Ph
Nu:
C C I PhNu
R
C CNu
R
H+
C CI PhNu
R H
- PhI
1,2-rearrangement
C CR Nu
NuR
1,5-insertion
Synthesis with Hypervalent Iodine
Synthesis of a Novel Phenyliodonium Betaine - MWJ
Synthesis with Hypervalent Iodine
Synthesis of a Novel Phenyliodonium Betaine - MWJ
Brianne Sawders (‘12) is currently exploring the limits of the Suzuki reaction with this betaine
Synthesis with Hypervalent Iodine
Other long-term targets of interest
R
I
NaOCl
pH 8.2
R
IOO
TsOHI
OOTsR
I-R and I-S isomers observed
I
OTs
H H
Chirality at Iodine
Aromatic Iodine
base
I
OTs
H
I
" "
iodaanthracene
decomposes
colorless green
Structural Studies
Structural Confirmation of an alkenyliodonium salt with a pyridine N-oxide moiety
Structural Studies
Synthesis of a novel phenyliodinium betaine
Structural Studies
First example of a protonated iodosobenzene derivative
N
HN
I 1) AcOOH, AcOH, 40 oC
2) TsOH, CH3CN
N
NI
OHTsO
19
Acknowledgements
My Students:Michelle Borkovec ‘06Alyssa Zimmerman ‘08.Heather Sopher ’09Michael Hughes ’09 Amanda Dechant ’09 Alex Ekstrom (biology) ’08 Melanie Knowlton ’09 Rocky Viggiano ‘09Samantha Kristufek ’11 Danielle Bittner ’11 Rachael Carmichael ’12 Brianne Sawders ’12Brandon Blanchard ‘12
Kathryn Sauka ‘14Alexis Rowley‘15Nick Burton‘15Anita Brkic ’15Johnny Lorigan’15 Zak Ekstrom ’15Bilal Hoblos ‘16