Rj. Ternansky et Cl. Jordan, THE RING-CLOSURE OF SUBSTITUTED AZETIDINONES - A NEW ROUTE TO [4.2.0]FUSED BETA-LACTAMS, Bioorganic & medicinal chemistry letters, 3(11), 1993, pp. 2443-2446
The synthesis of 1-carba-1-dethiacephalosporin nuclei is described. Th
e new route utilizes a readily-available penicillin derivative as star
ting material and features an intramolecular ring closure to form the
six-membered ring.