... 9) 2225~2232 (1991) Chemistry of O-Silylated Ketene Acetals: A Mild and Convenient Synthesis of fl-Lactam Antibiotics Yasuyuki K1TA,* Norio SHIBATA, Osamu TAMURA ... Chem, 51, 4150 (1986); Y. Kita, S. Akai, M. Yamamoto, M. Taniguchi and Y. Tamura, Synthesis, 1989 ...