作者:Sven Wiesner、Petra Walter、Arne Wagner、Elisabeth Kaifer、Hans-Jörg Himmel
DOI:10.1002/ejoc.201600978
日期:2016.10
step of these reactions. Electron-withdrawing as well as -donating substituents at the phenyl group increase the reaction rate. Quantum chemical computations did not reveal any correlation between either the enthalpy or Gibbs free energy of the N–C bond cleavage step and the experimentally determined first-order rate constants. Instead, the structural difference between the excited state generated by
评估了许多取代的苄基卤化物(15 个例子)与有机电子给体 2,3,5,6-四(四甲基胍基)吡啶的无金属光诱导还原 C-C 偶联反应。根据苄基上的取代基,可实现 50-95% 范围内的 C-C 偶联产物产率。通过最初形成的苄基-吡啶鎓盐的均裂 N-C 键裂解形成的光化学苄基自由基是这些反应的限速步骤。苯基上的吸电子和供电子取代基提高了反应速率。量子化学计算没有揭示 N-C 键裂解步骤的焓或吉布斯自由能与实验确定的一级速率常数之间的任何相关性。反而,