[Nickel-catalyzed [2 + 2 + 2] cocyclization and its application to the synthetic organic chemistry].
A nickel (0)-catalyzed asymmetric [2 + 2 + 2] cocyclization has been realized for the first time. This reaction involves conceptually new enantiotopic group selective formation of a nickelacyclopentadiene intermediate and produces an isoindoline derivative (73% ee, 78% conv. yield) and an isoquinoline derivative (54% ee, 62% yield) having benzylic chiral carbon centers. The synthesizing methods of biaryls using the nickel-catalyzed [2 + 2 + 2] cocyclization were also developed. Two ways for the synthesis of biaryl using [2 + 2 + 2] cocyclization were investigated: one method is that biaryls synthesized from alkyne having a phenyl group and 2 equivalents of acetylene, and the other method is that those were synthesized from alpha,omega-diyne having a phenyl group at the alpha-position and acetylene.
Sato
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Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
D000114:Acetylene / Q000737:chemistry; D000480:Alkynes / Q000737:chemistry; D002384:Catalysis; D009532:Nickel / Q000737:chemistry*; D009930:Organic Chemicals / Q000138:chemical synthesis*
D000480:Alkynes; D009930:Organic Chemicals; D009532:Nickel; D000114:Acetylene