Efficient Lipase-Catalyzed Kinetic Resolution and Dynamic Kinetic Resolution of β-Hydroxy Nitriles. A Route to Useful Precursors for γ-Amino Alcohols

Abstract

An efficient kinetic resolution of racemic β-hydroxy nitriles 1 was performed via Candida antarctica lipase (N-435)-catalyzed transesterification. A variety of racemic alkyl, aryl, and aryloxymethyl substituted β-hydroxy nitriles was efficiently transformed to the corresponding enantiomerically pure acetates (ee > 99% and conversion = 50%) with E values from 40 to >1000. The combination of the enzymatic kinetic resolution with a ruthenium-catalyzed alcohol racemization led to a dynamic kinetic resolution (ee's up to 99%, yields up to 85%).