title: Regiocontrolled intramolecular cyclizations of carboxylic acids to carbon-carbon triple bonds promoted by acid or base catalyst.
abstract: We systematically investigated, for the first time, the relationship between regioselectivity and acid/base effects in the cyclization reactions between carboxylic acids and carbon-carbon triple bonds. We found novel acid- and base-promoted cyclizations to selectively give isocoumarin or pyran-2(2H)-one and phthalide or furan-2(5H)-one skeletons, respectively, and established a catalytic version of regioselective heterocyclic ring synthesis. Density functional theory calculations and application to a short route to thunberginol A were also described. [reaction: see text].
authors.affiliation: Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan. uchiyama@mol.f.u-tokyo.ac.jp
authors.forename: Masanobu
authors.initials: M
authors.lastname: Uchiyama
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ozawa
authors.forename: Kazuya
authors.initials: K
authors.lastname: Takuma
authors.forename: Yotaro
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Yonehara
authors.forename: Kou
authors.initials: K
authors.lastname: Hiroya
authors.forename: Takao
authors.initials: T
authors.lastname: Sakamoto
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis; D002264:Carboxylic Acids / Q000138:chemical synthesis*; D002384:Catalysis; D003500:Cyclization; D005663:Furans / Q000138:chemical synthesis; D006571:Heterocyclic Compounds / Q000138:chemical synthesis; D031966:Hydrangea / Q000737:chemistry; D049934:Isocoumarins / Q000138:chemical synthesis; D011714:Pyrans / Q000138:chemical synthesis
chemical_list: D000900:Anti-Bacterial Agents; D002264:Carboxylic Acids; D005663:Furans; D006571:Heterocyclic Compounds; D049934:Isocoumarins; D011714:Pyrans; C079055:thunberginol A