Enzymatic resolution of alicyclic beta-lactams

Racemates of N-hydroxymethylated beta-lactams 4-6 were resolved through the lipase-catalyzed asymmetric acylation of the primary hydroxy group at the 6S stereogenic centre. High enantioselectivity (E > 200) was observed when the enzymatic reactions were performed in acetone with lipase PS as catalys t and vinyl butyrate as acyl donor. The hydrolysis of the enantiomeric azet idinones 4a-6a and 4b-6b resulted in the enantiomerically pure alicyclic be ta-amino acids 4c-6c and 4d-6d. When the less reactive enantiomers 4b-6b we re treated with NH4OH/MeOH, enantiomerically pure beta-lactams 4e-6e were f ormed. (C) 2000 Elsevier Science Ltd. All rights reserved.