title: Stereocontrolled total synthesis of the Stemona alkaloid (-)-stenine.
abstract: The Stemona alkaloid stenine (1), isolated from Stemona tuberosa of physiologically active stemonaceous plants, possesses the structurally novel and unique azepinoindole skeleton (B,C,D-ring system). We have achieved the asymmetric total synthesis of (-)-stenine (1), starting from 1,5-pentanediol (10). The key features are an intramolecular diastereoselective Diels-Alder reaction of the (E,E,E) triene 6, prepared in a convergent fashion from three components--dienyl chloride 7, dithiane 8, and chiral phosphonate 9--and efficient construction of the tricyclic A,B,D-ring system 29 through thermodynamically controlled regioselective enolization of the bicyclic ketone 25. In this article, we describe in detail the highly stereocontrolled total synthesis of (-)-stenine (1). These results should be useful for the asymmetric total synthesis of another, more complex. molecule: tuberostemonine (2), the synthesis of which has never been reported.
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Japan. morimoto@sci.osaka-cu.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Morimoto
authors.forename: M
authors.initials: M
authors.lastname: Iwahashi
authors.forename: T
authors.initials: T
authors.lastname: Kinoshita
authors.forename: K
authors.initials: K
authors.lastname: Nishida
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D010944:Plants / Q000737:chemistry; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D000470:Alkaloids; C441784:stenine