Kimihiko Goto

Asymmetric synthesis of isohaliclorensin, a key intermediate of bisquinolinylpyrrole alkaloid halitulin

Abstract A new enantioselective total synthesis of N-(3′-aminopropyl)-3-methylazacyclodecane, a partial structure of halitulin, has been achieved in eight steps with 14% overall yield. The key steps are the photochemical ring-expansion reaction of spirooxaziridine to lactam for constructing the azacyclodecane moiety and 1,4-stereoinductive methylation of the resulting lactam.

Synthesis and insecticidal efficacy of pyripyropene derivatives focusing on the C-1, C-7, and C-11 positions’ substituent groups

The C-1, C-7, and C-11 positions of pyripyropene A were chemically modified to improve the insecticidal activity. Some derivatives showed higher insecticidal activities against aphids than pyripyropene A. In particular, the derivative 5c, which possesses three cyclopropyl carbonyl groups at the C-1, C-7, and C-11 positions, had excellent insecticidal activity levels in field and laboratory trials.