Mechanisms of <i>syn</i>-Insertion of Alkynes and Allenes into Gold–Silicon Bonds: A Comprehensive Experimental/Theoretical Study
作者:Maximilian Joost、Laura Estevez、Sonia Mallet-Ladeira、Karinne Miqueu、Abderrahmane Amgoune、Didier Bourissou
DOI:10.1021/ja504024h
日期:2014.7.23
mechanistic study is reported for the syn-insertion of alkynes and allenes in the Au-Si bonds of complexes (R3P)Au-SiR'Ph2 (R = Ph, Me and R' = t-Bu, Ph). Kinetic experiments indicate that (i) the reaction is first-order in alkyne and gold silyl complex and (ii) it requires a rather low enthalpy of activation and a relatively large negative entropy of activation [ΔH(‡) = 13.7 (±1.6) kcal·mol(-1) and ΔS(‡) =
对炔烃和丙二烯在配合物 (R3P)Au-SiR'Ph2(R = Ph、Me 和 R' = t-Bu、Ph)的 Au-Si 键中的顺式插入进行了详细的机理研究。动力学实验表明(i)该反应在炔烃和金甲硅烷基络合物中是一级反应,(ii)它需要相当低的活化焓和相对较大的活化负熵 [ΔH(‡) = 13.7 (±1.6) kcal·mol(-1) 和 ΔS(‡) = -32.0 (±5.0) cal·mol(-1)·K(-1) 用于 (Ph3P)Au-Si(t-Bu)Ph2 与甲基的反应propiolate],符合双分子缔合转化。通过 DFT 计算探索了不同的机械路径。因此,发现该反应通过两步内球机制进行:(i)首先,炔烃与金甲硅烷基络合物配位形成 π 络合物;(ii) 随后的迁移插入步骤是速率确定并以协同方式发生。考虑到色散效应(B97D 泛函),理论上估计的活化焓 [ΔH(‡) = 11.5 kcal·mol(-1)]