研究室工作進展 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.
亮點介紹
在金屬有機化學中，β-氫消除和還原消除是被廣泛認可的基元反應。對于含有β-氫的金屬有機化合物，一般認為發生β-氫消除反應。對于這一基元反應，在有機化學人名反應Heck反應中已經诠釋的非常清楚。而我們研究發現，含有β-氫的金屬有機鹵化物發生β-氫消除反應并不是唯一的反應路徑，也可能發生還原消除反應生成碳-鹵鍵。烷基金屬有機鹵化物發生還原消除生成碳-鹵鍵近年來已經有文獻報道，但是都是沒有β-氫的金屬有機鹵化物。
本工作的主要創新點如下。（1）對于金屬有機化學基元反應的進一步認識；（2）通過串聯反應抑制β-氫消除，實現了含有β-氫的金屬有機鹵化物專一發生還原消除生成碳（sp3）-碘鍵。