Deracemization by Enantiodifferentiating Inversion in 1,3-Diols

摘要

The conversion of achiral molecules into enantiomerically pure chiral compounds is generally accomplished by one of two methods. On the one hand, a chiral reagent, catalyst, or auxiliary may be applied to effect an enantioselective synthesis, in whichasymmetric induction desymmetrizes the starting material to give molecules that are chiral in predominantly one sense. On the other, the use of simple achiral reagents gives a racemic mixture of chiral molecules, which may then be resolved by interaction with a chiral agent. While the first of these methods may lead to, in principle, 100% conversion of an achiral starting compound into enantiomerically pure product, the second is limited to 50% conversion in most cases. Only certain circumstances allow"dynamic resolution", wherein equilibration of the starting enantiomers permits the enan-tiodifferentiating reagent catalyst, or complexing agent to deliver the enantiomerically pure product in quantitative yield of (Scheme 1).