The primary monoesters of diol compounds were formed exclusively in the reaction with vinyl acetate and Aspergillus niger lipase for 24 similar to 72 h. Various diol compounds which included 1,3-butanediol, 1,4-butanediol, 1,5-hexanediol, 1-phenyl-1,2-ethanediol, 1-phenyl-1,3-propanediol, 2, 3, or 4-hydroxybenzyl alcohol, methyl 2, 3-O-acetyl-D-glycopyranosides and phenyl 1-thio-beta-D-xylopyranoside have been examined and showed nearly 100% regioselectivity.