Thiocrown ether additive effects on diastereoselectivity of the lipase-catalyzed reaction: Preparation of optically active 3-hydroxy-2-methylalkanenitriles through a double enzymatic reaction strategy

The additive effect on diastereoselectivity towards the lipase-catalyzed hy drolysis of acetates of 3-hydroxy-2-methyl- or 3-hydroxy-2-ethylalkanenitri les has been investigated. Diastereoselectivity was not influenced by thioc rown ether additives, although a significant modification of enantioselecti vity was observed. Origin of the diastereoselectivity of the lipase-catalyz ed reaction was thus evidently different from that of enantioselectivity. B ased on these results, an easy preparation of optically active 3-hydroxy-2- methylpentanenitrile and 3-hydroxy-2-methylbutanenitrile have been demonstr ated through lipase-catalyzed reaction by a double enzymatic reaction strat egy.