Enantioselective acylation of a beta-lactam intermediate in the synthesis of loracarbef using penicillin G amidase

Penicillin G amidase from E. coli has been shown to selectively acylate, in an efficient manner, the (2R,3S) isomer of a cis, racemic azetidinone intermediate used in a synthesis of loracarbef, a carbacephalosporin antibiotic. The acylation occurs using methyl phenylacetate (MPA) and using methyl phenoxyacetate (MPOA) as the acylating agents. The enzyme displays similar enantioselectivity with MPOA or MPA.