Kinetic Resolution of Secondary Alcohols. Enantioselective Acylation Mediated by a Chiral (Dimethylamino)pyridine Derivative

摘要

Kinetic resolution of certain chiral alcohols or their ester derivatives can be carried out using the lipase/esterase family of acyl transfer catalysts. If the enantiomers differ in relative reactivity by a factor (s) of 100 or more, >40% recovery ofeach enantiomer is theoretically possible with >90% ee. However, lower enantioselectivities s in the range of 10--30 are often encountered, and purified yields can be considerably lower. In such cases the less reactive enantiomer can still be obtained with high ee by forcing the conversion well past the theoretical 50% optimum because eventual destruction of the more reactive enantiomer compensates for "errors" in enanti-oselective recognition. However, higher ee is achieved at the, cost of decreased material recovery.