First total syntheses of the phytotoxins solanapyrones D and E via the domino Michael protocol.

Hisahiro Hagiwara, Katsuhiro Kobayashi, Shigeki Miya, Takashi Hoshi, Toshio Suzuki, Masayoshi Ando, Tetsuji Okamoto, Masaki Kobayashi, Isao Yamamoto, Satoru Ohtsubo, Michiharu Kato, Hisashi Uda

Index: J. Org. Chem. 67(17) , 5969-76, (2002)

Full Text: HTML

Abstract

The phytotoxins solanapyrones D (1) and E (2) have been synthesized from the decalone prepared by the domino Michael reaction of the kinetic enolate of optically pure acetylcyclohexene with methyl crotonate. The decalone was transformed into a solanapyrone core by equilibration into thermodynamically stable trans-decalone (11), dehydroxylation, and dehydration. Condensation of a methyl acetoacetate equivalent followed by cyclization installed a pyrone moiety. Introduction of a formyl or hydroxymethyl unit into the pyrone ring via Pummerer related reactions furnished solanapyrones D (1) and E (2).