Synthesis of 2-azetidinones incorporating carbenechromium(O) moieties and their use in the preparation of penicillin- And cephalosporin-containing peptides

1. Sierra, M.A.
2. Rodríguez-Fernández, M.
3. Casarrubios, L.
4. Gómez-Gallego, M.
5. Mancheño, M.J.