ASYMMETRIC SYNTHESIS OF (ALPHA)-SUBSTITUTED-(ALPHA)- CYANOMETHYL ALCOHOLS

摘要

Asymmetric Synthesis Of .alpha.-Substituted-.alpha.-cyanomethyl Alcohols The invention concerns a process for the preparation of an .alpha. substituted- .alpha. -cyanomethyl alcohol enantiomer of formula I I wherein the group R1 is an alkenyl, alkynyl, aryl or heteroaryl group by reacting an aldehyde of formula II II with hydrogen cyanide in the presence of a cyclic dipeptide enantiomer at a temperature below ambient temperature. The process enables the preparation of compounds of formula I in high yield and high enantiomeric excess. The enantiomers of formula I may be used as intermediates for the preparation of chiral pyrethroids and chiral arylethanolamines. The invention also embraces cyclic dipeptide enantiomers, processes for the preparation of chiral pyrethroids and chiral arylethanolamines from .alpha. substituted- .alpha. -cyanomethyl alcohol enantiomers of formula I and chiral pyrethroids and chiral ethanolamines and the chiral pyrethroids and chiral ethanolamines prepared thereby.