Kinetic resolutions and enantioselective transformations of 5-(acyloxy)pyrrolinones using Candida antarctica lipase B:: Synthetic and structural aspects

Various 5-(acyloxy)pyrrolinones have been prepared in enantiomerically pure form by means of an enzymatic resolution or an asymmetric transformation. Either enantiomer is obtained using the same enzyme, Candida antarctica lipase B, by modification of the procedure from transesterification to esterification. N-Acyl-5-(acyloxy)pyrrolinones 1 (R-2 = acyl) are synthesized by applying this method with 100% yield and >99% ee. To rationalize the observed enantioselectivity and the substituent effects of these reactions both empirical models and molecular modeling studies have been used, and a qualitative agreement was found between the results from these studies and the experimental results.