Sterically Directed Functionalization of Aromatic C−H Bonds: Selective Borylation Ortho to Cyano Groups in Arenes and Heterocycles
作者:Ghayoor A. Chotana、Michael A. Rak、Milton R. Smith
DOI:10.1021/ja0428309
日期:2005.8.1
Ir-catalyzed borylations of 4-substituted benzonitriles are described. In contrast to electrophilic aromatic substitutions and directed ortho metalations, C-H activation/borylation enables functionalization at the 2-position, adjacent to the cyano group, when the 4-subsitutent is larger than cyano. When an excess of borane reagent is used, diborylation can be achieved with a single regioisomer being
描述了 4-取代苄腈的 Ir 催化硼化。与亲电芳香取代和定向邻位金属化相反,当 4-取代基大于氰基时,CH 活化/硼酸化能够在与氰基相邻的 2-位进行官能化。当使用过量的硼烷试剂时,在某些情况下可以通过形成单一区域异构体来实现二硼化。还报道了空间定向硼酸化扩展到氰基取代的五元和六元环杂环。