Abstract The substrate recognition of Candida antarctica lipase B (CAL-B) in the acylation of nucleosides was revealed through rational substrate engineering for the first time. CAL-B displayed lower activities and excellent 5′-regioselectivities (94 to> 99%) in the acylation of ribonucleosides 1f–1j as compared to those in the acylation of 2′-deoxynucleosides 1a– 1e. The excellent regioselectivities might be attributed to the favorable steric hindrance of ...
