A Pyridine–Pyridine Cross‐Coupling Reaction via Dearomatized Radical Intermediates
作者:J. Luke Koniarczyk、Jacob W. Greenwood、Juan V. Alegre‐Requena、Robert S. Paton、Andrew McNally
DOI:10.1002/anie.201906267
日期:2019.10.14
and cyanopyridines using B2 pin2 as an electron-transfer reagent. Complete regio- and cross-selectivity are observed when forming a range of valuable 2,4'-bipyridines. Phosphonium salts were found to be the only viable radical precursors in this process, and mechanistic studies indicate that the process does not proceed through a Minisci-type coupling involving a pyridyl radical. Instead, a radical-radical
使用B2 pin2作为电子转移试剂,在吡啶基phospho盐和氰基吡啶之间开发了吡啶-吡啶偶联反应。当形成一系列有价值的2,4'-联吡啶时,观察到完全的区域选择性和交叉选择性。发现os盐是该过程中唯一可行的自由基前体,并且机理研究表明,该过程不会通过涉及吡啶基的Minisci型偶联进行。取而代之的是,硼烷基phospho吡啶基和硼基稳定的氰基吡啶基之间的自由基-自由基偶联过程解释了CC键形成步骤。