Asymmetric Total Synthesis of an Important 3-(Hydroxymethyl)carbacephalosporin

Carbacephalosporins have gained much attention as important antibacterial agents. Recently, 3-(hydroxymethyl)carbacephalosporins have been linked to quinolones for the production of multifunctional antibiotics. A short, practical asymmetric total synthesis of carbacephalosporin 3, suitable for conjugating to other chemical moieties, is reported. The synthesis was achieved by Mitsunobu cyclization of dipeptide 12, prepared from l - erythro - anti -β-hydroxy-α-amino acid 11, and subsequent Horner−Wadsworth−Emmons cyclization of ketone 16 .