title: Total Synthesis of (-)-Lepadiformine A Utilizing Hg(OTf)2-Catalyzed Cycloisomerization Reaction.
abstract: A cytotoxic marine alkaloid (-)-lepadiformine A (1) possesses a unique structure characterized by the trans-1-azadecalin AB ring system fused with the AC spiro-cyclic ring. In this research, we found that a cycloisomerization reaction from amino ynone 2 to a 1-azaspiro[4.5]decane skeleton 3, corresponding to the AC ring system of 1, is promoted by Hg(OTf)(2). Thus, we have accomplished the efficient total synthesis of (-)-lepadiformine A in 28% overall yield by featuring the novel Hg(OTf)(2)-catalyzed cycloisomerization.
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University , Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nishikawa
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University , Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Seiho
authors.initials: S
authors.lastname: Kikuchi
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University , Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Shinnosuke
authors.initials: S
authors.lastname: Ezaki
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University , Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Koyama
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University , Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Nokubo
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University , Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kodama
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University , Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Tachi
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University , Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Morimoto
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D002384:Catalysis; D003500:Cyclization; D008386:Marine Biology; D008698:Mesylates / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism; D014561:Urochordata / Q000737:chemistry
chemical_list: D000470:Alkaloids; D008698:Mesylates; C431548:lepadiformine; C012077:trifluoromethanesulfonic acid