Regioselective Syntheses of Substituted Pyridines and 2,2′-Bipyridines by Cobalt-Catalyzed [2+2+2] Cycloaddition of α,ω-Diynes with Nitriles
作者:Sentaro Okamoto、Yu-ki Sugiyama
DOI:10.1055/s-0030-1260068
日期:2011.7
2-bis(diphenylphosphino)ethane-cobalt(II) chloride-zinc catalyst in 1-methylpyrrolidin-2-one at room temperature to 50 ˚C, α,ω-diynes reacted with nitriles by a [2+2+2] cycloaddition pathway to give annulated pyridines or 2,2′-bipyridines. The regioselectivity of the reaction is controlled by a combination of steric and electronic effects. The reaction of diynes with a terminal trimethylsilyl group gave the