Synthesis of new ( R)-secondary carbinols with different structures via enzymatic resolution

Abstract

The present study deals with the biocatalytic enantioselective synthesis of 19 new chiral alcohols with alkyl (C 11–C 19) and phenyl, substituted phenyl, heteroaromatic, and naphthyl groups 4a– 4z with an ( R)-configuration and high enantiomeric excess (∼100%). The corresponding ketones 1a– 1z were synthesized and then reduced with NaBH 4 to their racemic alcohols 2a– 2z, which were converted into their racemic acetyl derivatives 3a– 3z. Enzymes of four different types were used for the enantioselective hydrolysis of these acetyl compounds 3a– 3z. The optimal reaction conditions for these four enzymes were established by investigating the enantiomeric excesses by chiral HPLC. Amano lipase from Burkholderica cepacia ( Pseudomonas cepacia) AL-PS was determined as the best enzyme in this work. This study presents an environmentally friendly and green chemistry method for the synthesis of these new ( R)-chiral carbinols 4a– 4z.