Cobalt-Catalyzed Intermolecular [2 + 2 + 2] Cycloaddition for the Synthesis of 1,3-Cyclohexadienes
作者:Gerhard Hilt、Anna Paul、Klaus Harms
DOI:10.1021/jo800735x
日期:2008.7.1
A cobalt(I)-catalyzed [2 + 2 + 2] cycloaddition reaction between an internal acceptor-substituted alkyne and a terminal alkene leads to the formation of regiochemically enriched polysubstituted 1,3-cyclohexadiene derivatives in acceptable yields when methyl butynoate is used, whereas regiochemically pure products are formed in good yields form phenyl propyonate. The concurrent cyclotrimerization reaction
当使用丁酸甲酯时,内部受体取代的炔烃与末端烯烃之间的钴(I)催化的[2 + 2 + 2]环加成反应会以可接受的产率形成区域化学富集的多取代的1,3-环己二烯衍生物,而区域化学纯的产品是由丙酸苯基酯以高收率形成的。炔烃与相应的苯衍生物同时进行的环三聚反应取决于炔烃的空间体积,并且在空间位阻较大的炔烃上会大大降低。