Applications of Metalated Cyclopropenone Ketals in a General Synthesis of Cyclopropenones. An Efficient Synthesis of the Antibiotic Penitricin ... Masahiko Isaka, Satoshi Matsuzawa, Shigeru Yamago, Satoshi Ejiri, Yoshimitsu Miyachi, and Eiichi Nakamura* Department of Chemistry, Tokyo Institute of Technology, Meguro, Tokyo 152, Japan Received June 26, 1989 Summary: A variety of substituted cyclopropenones, in- cluding the antibiotic penitricin ...