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
在室温至50℃下,在1-甲基吡咯烷-2-酮中存在1,2-双(二苯基膦基)乙烷-氯化钴(II)-锌催化剂时,α,ω-二炔与腈通过[ 2 + 2 + 2]环加成途径得到环状吡啶或2,2'-联吡啶。反应的区域选择性由空间效应和电子效应的组合来控制。二炔与末端三甲基甲硅烷基的反应仅给出了相应的3-(三甲基甲硅烷基)吡啶。这些产物可以被原甲硅烷基化或卤代甲硅烷基化,得到相应的质子化或卤化吡啶或2,2'-联吡啶。 环加成-杂环-均相催化-吡啶-区域选择性