Regioselective esterification of polyhydroxylated steroids by Candida antarctica lipase B

Article abstract of DOI:10.1016/S0040-4020(01)89326-1

The regioselectivity of Candida antarctica lipase B towards the acetylation of polyhydroxylated steroids has been systematically investigated. The enzyme showed a marked preference for the alcoholic moieties on the A ring and: on the steroidal side chain, making it possible the selective acylation at the positions 3 or 21 of polyhydroxy steroids. Acylation with the synthetically useful esters chloroacetate and levulinate was also accomplished, whereas esterification with benzoate and pivaloate was unsuccessful.