smallest IBn and iPr2Im NHC ligands. Using the larger IMes carbene resulted in a 66:34 mixture of silylation and hydroarylation products, and the largest NHC, IPr, gave exclusive conversion to the hydroarylation product, C6F5CH2CH2SiMe3. DFT calculations are provided that give insight into the mechanism and key reaction steps, such as the relative difficulty of the critical β-Sn, Ge, and Si elimination
一系列Ni(0)化合物由电子相似的N-杂环卡宾(NHC)辅助
配体(含5%V bur的范围)支撑,用作芳基C–H键甲
硅烷基化,杀菌和
锡烷基化的催化剂。尽管催化剂的静止状态几乎没有结构变化,但NHC的空间体积极大地影响了C–H官能化的选择性,从而产生了新的碳-杂原子键与烯烃加氢芳基化反应。研究由下反应进行6 ˚F 5 H和H 2 C═CHER 3(ER 3 = SnBu 3,GePh 3,森达3),使用催化量的Ni(COD)的2NHC
配体IPr,IMes,IBn和i Pr 2 Im。催化的C–H
锡烷基化反应可得到C 6 F 5 SnBu 3,而且所有
配体都很容易。催化C-H germylation反应比甲
锡烷基化更加困难,但使用H证明2 C═C
HGePh 3得到C,6 ˚F 5 GePh 3为所有,但最大的NHC。最大的NHC IPr给出了96:4的氢芳基化产物C 6 F 5 CH 2 CH 2