Studies on the enantioselectivity in the lipase-catalyzed synthesis of monoacylglycerols from isopropylidene glycerol

The regioselective lipase-catalyzed acylation of isopropylidene glycerol using different vinyl esters as acyl donors in toluene was studied. Reaction progress and enantioselectivity were monitored by gas chromatography using a permethylated beta-cyclodextrin phase. All vinyl esters were completely converted after 20 to 24 h and it was found that the S-enantiomer reacted faster. Lower enantiomeric excess were found using e. g. vinyl palmitate (18 %ee) compared to e. g. vinyl butyrate (42 %ee) with crude lipase from Pseudomonas cepacia. Immobilization using the sol-gel method resulted in higher remaining activities (up to 69%) and increased enantioselectivity E (up to 8.5).