Total Synthesis of (±)-Stemodinone via an Efficient Ring-Exchange Strategy
journal contributionposted on 26.09.2001, 00:00 by Tetsuaki Tanaka, Kazuo Murakami, Atsushi Kanda, Debasis Patra, Sachiko Yamamoto, Norifumi Satoh, Sang-Won Kim, S. M. Abdur Rahman, Hiroaki Ohno, Chuzo Iwata
A total synthesis of (±)-stemodinone, a tetracyclic stemodane diterpene, from the known tricyclic methyl olefin 11 is described. The key steps involve an efficient ring-exchange reaction and palladium(0)-catalyzed lactone migration. The ring-exchange strategy for controlling the stereochemistry was based on an initial Diels−Alder reaction to form a new ring followed by cleavage of the original ring. Cleavage of the original ring of the Diels−Alder adduct 9 was achieved by an initial regio- and chemoselective Baeyer−Villiger oxidation followed by the Pd(0)-catalyzed lactone-migration reaction reported by us.