A chromium/2,2′-bipyridine-catalyzed annulation reaction of 2-biarylmagnesium reagents with alkynes is reported. The reaction is applicable to a variety of aryl- and/or alkyl-substituted internal alkynes as well as 2-biaryl and related Grignard reagents, thus affording phenanthrene derivatives in moderate to good yields. The reaction proceeds at the expense of excess alkyne as a hydrogen acceptor and
据报道,
铬/
2,2'-联吡啶催化2-联芳基
镁试剂与
炔烃的环化反应。该反应适用于各种芳基和/或烷基取代的内部
炔烃以及2-联芳基和相关的
格氏试剂,因此以中等至良好的产率提供了
菲衍
生物。该反应以过量的炔作为氢受体为代价进行,因此不需要外部氧化剂。
氘标记实验阐明了反应机理,该机理可能涉及
铬上多个分子内C–H活化过程。