Enantioselective transesterification of a tertiary alcohol by lipase A from Candida antarctica

Chiral tertiary alcohols and their esters represent important flavor compounds and are useful building blocks. Unfortunately, they are accepted by only a few lipases/esterases as substrates and enantioselectivity is usually very low. We report here a highly enantioselective transesterification of the tertiary alcohol 2-phenylbut-3-yn-2-ol using lipase A from Candida antarctica (CAL-A). Under optimized conditions, the corresponding acetate was obtained with 94%ee at 35% conversion equivalent to an enantioselectivity factor of E=65. In contrast, enantioselective hydrolysis of the racemic acetate was not feasible as this is very prone to autohydrolysis.