title: Catalytic cycloisomerization of enynes by using a nickel-zinc-acid system.
abstract: Catalytic cycloisomerization of enynes has been accomplished in the presence of an Ni0-PPh3-Zn-carboxylic acid or -ZnCl2 system. A nickel(I)-hydride complex, thought to be generated by reduction of the protonated nickel(II) complex with Zn, is proposed as the catalytic species. This cycloisomerization shows reactivity behavior that is different from that of a conventional metal-catalyzed reaction. In particular, in the reaction with (E)-enynes, the catalytic system has a selectivity that favors the formation of the 1,3-diene over the 1,4-diene. In addition, this catalytic system has been applied to the domino cyclization of dienynes for the construction of tricyclic compounds.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya City University, Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan. ikeshin@phar.nagoya-cu.ac.jp
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Ikeda
authors.forename: Natsuko
authors.initials: N
authors.lastname: Daimon
authors.forename: Reiko
authors.initials: R
authors.lastname: Sanuki
authors.forename: Kazunori
authors.initials: K
authors.lastname: Odashima
mesh_terms: D000143:Acids; D000475:Alkenes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009532:Nickel / Q000737:chemistry; D010165:Palladium / Q000737:chemistry; D019163:Reducing Agents / Q000737:chemistry; D015032:Zinc / Q000737:chemistry
chemical_list: D000143:Acids; D000475:Alkenes; D000480:Alkynes; D019163:Reducing Agents; D010165:Palladium; D009532:Nickel; D015032:Zinc