Preparative and mechanistic aspects of interesterification reactions on diols and peracetylated polyphenolic compounds catalysed by lipases

The lipases from porcine pancreas and Candida cylindracea have been successfully used in carrying out simple, efficient and potentially useful biotransformations on diols and peracetylated polyphenolic esters. It has been observed that the esterification reactions on 1,2-diols are highly regioselective and the primary hydroxyl group is exclusively esterified over the one at the secondary position. The results on lipase-mediated deacylation reactions on the mixed diesters of 1,2-diols suggest that during deacylation, the migration of acyl group takes place. Additionally, the lipase-catalysed deacetylations on peracetates of polyhydroxy aromatic esters substantiate the Schiff's base complex hypothesis proposed earlier by us for the regiospecific deacetylations on peracetates of polyhydroxyaryl-alkyl ketones and benzopyranones.