INVESTIGATION OF THE REGIOSELECTIVITY OF SOME ESTERIFICATIONS INVOLVING METHYL 4,6-O-BENZYLIDENE D-PYRANOSIDES AND PSEUDOMONAS-FLUORESCENS LIPASE

Using Pseudomonas fluorescens lipase in vinyl acetate, the methyl 4,6-O-benzylidene-alpha-D-pyranosides 1 and 6-8 have been esterified with very high selectivity to afford the C-2 acetates 3 and 10-12, respectively. In contrast the methyl 4,6-O-benzylidene-beta-D-pyranosides 2 and 9 are acetylated under the same conditions to give the C-3 esters 5 and 13 with high/exquisite regioselectivity.