研究室工作进展 Jan. 5th, 2015
Transfer of Aryl Halide to Alkyl Halide: Reductive Elimination of Alkylhalide from Alkylpalladium Halides Containing syn-β-Hydrogen Atoms
Wei Hao, Junnian Wei, Weizhi Geng, Wen-Xiong Zhang, and Zhenfeng Xi*
Angew. Chem. Int. Ed. 2014, 53, 14533-14537.
Dedicated to Prof. Tamotsu Takahashi on the occasion of his 60th birthday
β-Hydride abstraction is a well-accepted elementary step for catalytic cycles in organometallic chemistry. It is usually anticipated that alkylpalladium halides containing syn-β-hydrogen atoms will undergo b-hydride abstraction to afford the Heck-type products. However, this study discloses that the above general knowledge is only conditionally correct. Our experimental results demonstrate that the reductive elimination of alkylhalides from alkylpalladium halides containing syn-β-hydrogen atoms may surpass the β-hydride abstraction or even become exclusive in certain cases.
亮点介绍
在金属有机化学中，β-氢消除和还原消除是被广泛认可的基元反应。对于含有β-氢的金属有机化合物，一般认为发生β-氢消除反应。对于这一基元反应，在有机化学人名反应Heck反应中已经诠释的非常清楚。而我们研究发现，含有β-氢的金属有机卤化物发生β-氢消除反应并不是唯一的反应路径，也可能发生还原消除反应生成碳-卤键。烷基金属有机卤化物发生还原消除生成碳-卤键近年来已经有文献报道，但是都是没有β-氢的金属有机卤化物。
本工作的主要创新点如下。（1）对于金属有机化学基元反应的进一步认识；（2）通过串联反应抑制β-氢消除，实现了含有β-氢的金属有机卤化物专一发生还原消除生成碳（sp3）-碘键。