title: Efficient and selective formation of unsaturated carboxylic and phenylacetic acids from diketene.
abstract: A nickel catalyst promotes the multicomponent coupling reaction of diketene, an alkyne, and Me2Zn to provide 3-methylene-4-hexenoic acids in excellent yields. Under similar conditions, the combination of the nickel catalyst and Et2Al(OEt) promotes a cycloaddition reaction involving dimerization of an alkyne to furnish phenylacetic acids. In the presence of PPh3, a formal [2+2+1+1] cycloaddition reaction proceeds to afford regioisomeric phenylacetic acids via cleavage of the C=C bond.
authors.affiliation: Graduate School of Engineering, Nagasaki University, 1-14 Bunkyo machi, Nagasaki 852-8521 (Japan) http://www.cms.nagasaki-u.ac.jp/lab/yuuki/index.html.
authors.forename: Takamichi
authors.initials: T
authors.lastname: Mori
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Akioka
authors.forename: Hisaho
authors.initials: H
authors.lastname: Kawahara
authors.forename: Ryo
authors.initials: R
authors.lastname: Ninokata
authors.forename: Gen
authors.initials: G
authors.lastname: Onodera
authors.forename: Masanari
authors.initials: M
authors.lastname: Kimura
keywords: carboxylic acids; cycloaddition; nickel; synthetic methods; zinc