Kinetic Resolutions - The Stoltz Group

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Worked well (typically ~60% conv., > 80% ee, s > 15) Me 3 Si OH R OH OH OH Ph Sharpless Epoxidations - Examples OH OH OH R OH SiMe3 OH OH R OH OH Ph OH Ph OH t-Bu Sometimes selectivities up to "700" were observed (determined by measuring k fast and k slow separately) Did not work so well: H • H OH OH OH OH Sharpless, et. al., J. Am. Chem. Soc., 1981, 103, 6237 J. Am. Chem. Soc., 1987, 109, 5565 J. Am. Chem. Soc., 1988, 110, 2978 14
t-Bu R 3 OH R 1 R 1 R 1 (±)- + + R 2 N N Mn MeO O Cl O OMe t-Bu Epoxidation of Allylic Alcohols - Salen too! (Adam) (R,R)-10 10 mol% Catalyst 10 or 11 t-Bu 20 mol% PPNO 60 mol% PhIO CH 2Cl 2, r.t. Enantiomer of alcohol depends on catalyst used (10 and 11 give opposite enantioenrichment) Epoxide ee's 50-80%, Alcohol ee's < 50% (10 -50% conv.), s = 1.5-12.9 Oxidation of alcohol to ketone over epoxidation often problematic R 3 OH R 2 N N Mn O R 3 OH R 2 t-Bu O Cl O t-Bu t-Bu (S,S)-11 t-Bu R 3 O R 2 PPNO R 1 N O Adam, et. al., J. Org. Chem., 2001, 66, 5796 Selectivity in Salen Epoxidations of Allylic Alcohols O t-Bu N O Mn 2 N HO O t-Bu Ph 3 1 - A 1,3 Interaction 1 2 - Hydrogen Bonding 3 - Katsuki Trajectory H Me t-Bu Me Ph H OH Katsuki Trajectory O Mn O R L is forced away from the bulky salen tert-butyl groups, especially when R L is aromatic 1, 2, and 3 require that the (S)-enantiomer be the more reactive (when the catalyst is derived from the (S,S)-salen ligand, as shown) N R S R L Adam, et. al., J. Org. Chem., 2001, 66, 5796 Katsuki, et. al., J. Mol. Cat. A, 1996, 113, 87 15
Page 1 and 2: N Me N Kinetic Resolutions Episode
Page 3 and 4: (±)- Evans - Oxazolidinone Acylati
Page 5 and 6: Cl (±)- R 1 R 1 = Ar OH R 2 R 2 =
Page 7 and 8: (±)- (±)- Et 3N Me (±)- Ph Ph OH
Page 9 and 10: BocHN (±)- N N Tripeptides for Acy
Page 11 and 12: CO2R PPh3 N N RO2C RO2C CO2R HN NH
Page 13: Nishiyama, Sekar (our very own!) n
Page 17 and 18: (±)- Gardiner (±)- (±)- MeO 2C P
Page 19 and 20: Sharpless Et t-Bu Proposed Asymmetr
Page 21: R (CH2)3CH3 CH 3 (CH2)11CH3 (CH 2 )

Kinetic Resolutions - The Stoltz Group

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