title: C3-symmetric trisimidazoline-catalyzed enantioselective bromolactonization of internal alkenoic acids.
abstract: A method for conducting enantioselective bromolactonization reactions of trisubstituted alkenoic acids, using the C(3)-symmetric trisimidazoline 1 and 1,3-dibromo-5,5-dimethyl hydantoin as a bromine source, has been developed. The process generates chiral δ-lactones that contain a quaternary carbon. The results of studies probing geometrically different olefins show that (Z)-olefins rather than (E)-olefins are favorable substrates for the process. The method is not only applicable to acyclic olefin reactants but can also be employed to transform cyclic trisubstituted olefins into chiral spirocyclic lactones. Finally, the synthetic utility of the newly developed process is demonstrated by its application to a concise synthesis of tanikolide, an antifungal marine natural product.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamada-oka, Suita, Osaka, 565-0871, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Murai
authors.forename: Akira
authors.initials: A
authors.lastname: Nakamura
authors.forename: Tomoyo
authors.initials: T
authors.lastname: Matsushita
authors.forename: Masato
authors.initials: M
authors.lastname: Shimura
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Fujioka
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D000935:Antifungal Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D002384:Catalysis; D006842:Hydrocarbons, Brominated / Q000138:chemical synthesis* / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry*; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D008386:Marine Biology; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D000935:Antifungal Agents; D001688:Biological Products; D006842:Hydrocarbons, Brominated; D007093:Imidazoles; D007783:Lactones; C400156:tanikolide