Forro_2013_J.Mol.Catal.B.Enzym_98_92

The ester function of ethyl cis-(+/-)-2-hydroxycyclopentane-1-carboxylate [(+/-)-1] and ethyl (+/-)-5-hydroxycyclopent-1-enecarboxylate [(+/-)-2] was demonstrated to undergo hydrolysis, as a side-reaction, during asymmetric (E > 200) O-acylation with Candida antarctica lipase B (CAL-B) as catalyst and vinyl acetate as acyl donor in t-BuOMe at 30 C. This competition of acylation and undesirable hydrolysis draws attention to CAL-B-catalyzed non-hydrolytic resolutions where the substrates contain any hydrolysable functions. Enantiomerically enriched cis-2-hydroxycyclopentane-1-carboxylic acid (ee = 90%) and 5-hydroxycyclopent-1-enecarboxylic acid (ee = 47%) were prepared through de novo CAL-B-catalyzed hydrolysis of (+/-)-1 and (+/-)-2 with added H2O in t-BuOMe at 30 C.