Catalytic cycloisomerization of enynes by using a nickel-zinc-acid system.
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.
Ikeda
Shin-ichi
S
Graduate School of Pharmaceutical Sciences, Nagoya City University, Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan. ikeshin@phar.nagoya-cu.ac.jp
Daimon
Natsuko
N
Sanuki
Reiko
R
Odashima
Kazunori
K
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
D000143:Acids; D000475:Alkenes; D000480:Alkynes; D019163:Reducing Agents; D010165:Palladium; D009532:Nickel; D015032:Zinc