Preparative and mechanistic aspects of inter-estification reactions on diols and peracetylated polyphenolic compounds catalysed by lipases
The lipases from porcine pancreas and Cundida cylindracea have been successfully used in carrying out simple, efficient and potentially useful biotrans- formations on diols and peracetylated polyphenolic esters. It has been observed that the esterification reactions on 1,Zdiols are highly regiaselective 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. Addition- ally, the lipase-catalysed deacetylations on peracetates of polyhydroxy aromatic es- ters substantiate the Schiff's base complex hypothesis proposed earlier by us for the regiospecific deacetylations on peracetates of polyhydroxyaryl-alkyl ketones and