title: Nickel-catalyzed intermolecular [3 + 2 + 2] cocyclization of ethyl cyclopropylideneacetate and alkynes. Synthesis of seven-membered carbocycles.
abstract: The [3 + 2 + 2] cocyclization of ethyl cyclopropylideneacetate (1a) and various alkynes proceeded smoothly in the presence of Ni(cod)2-PPh3. The cycloheptadiene derivatives were synthesized in highly selective manners. The unique reactivity of 1a was essential for the progress of the reaction. The observed regioselectivity of the product formation and the mechanism of the reaction are discussed.
authors.affiliation: Department of Chemistry, Faculty of Science, Tokyo University of Science, Kagurazaka, Shinjuku, Tokyo, Japan. ssaito@rs.kagu.tus.ac.jp
authors.forename: Shinichi
authors.initials: S
authors.lastname: Saito
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Komagawa
authors.forename: Isao
authors.initials: I
authors.lastname: Azumaya
authors.forename: Manami
authors.initials: M
authors.lastname: Masuda
mesh_terms: D000085:Acetates / Q000737:chemistry*; D000466:Alkadienes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D003508:Cycloheptanes / Q000138:chemical synthesis; D003521:Cyclopropanes / Q000737:chemistry*; D047028:Macrocyclic Compounds / Q000138:chemical synthesis*; D008956:Models, Chemical; D009532:Nickel / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000085:Acetates; D000466:Alkadienes; D000480:Alkynes; D003508:Cycloheptanes; D003521:Cyclopropanes; D047028:Macrocyclic Compounds; C007650:ethyl acetate; D009532:Nickel