title: Enantioselective total synthesis of pinnaic acid and halichlorine.
abstract: The enantioselective total synthesis of the bioactive marine natural products pinnaic acid and halichlorine is reported in detail. Our total synthesis features the construction of the five-membered ring and C9 and C13 stereogenic centers through a palladium-catalyzed trimethylenemethane [3+2] cyclization; the installation of the nitrogen atom through a regioselective Beckmann rearrangement of a poorly reactive ketone; the stereoselective cyclization of the spiro ring through a four-step, one-pot hydrogenation-cyclization; and efficient connection of the sterically hindered lower chain through a reduced-pressure cross olefin metathesis reaction.
authors.affiliation: Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai 980-8577 (Japan), Fax: (+81) 22-217-6204.
authors.forename: Shu
authors.initials: S
authors.lastname: Xu
authors.forename: Daisuke
authors.initials: D
authors.lastname: Unabara
authors.forename: Daisuke
authors.initials: D
authors.lastname: Uemura
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Arimoto
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D008968:Molecular Conformation; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000470:Alkaloids; D001688:Biological Products; D013141:Spiro Compounds; C412666:halichlorine; C412665:pinnaic acid
keywords: cyclization; metathesis; natural products; stereoselectivity; total synthesis