Beijing National Laboratory of Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
J Am Chem Soc. 2013 Jan 30;135(4):1264-7. doi: 10.1021/ja311689k. Epub 2013 Jan 15.
The first manganese-catalyzed aromatic C-H alkenylation with terminal alkynes is described. The procedure features an operationally simple catalyst system containing commercially available MnBr(CO)(5) and dicyclohexylamine (Cy(2)NH). The reaction occurs readily in a highly chemo-, regio-, and stereoselective manner delivering anti-Markovnikov E-configured olefins in high yields. Experimental study and DFT calculations reveal that (1) the reaction is initiated by a C-H activation step via the cooperation of manganese and base; (2) manganacycle and alkynylmanganese species are the key reaction intermediates; and (3) the ligand-to-ligand H-transfer and alkynyl-assisted C-H activation are the key steps rendering the reaction catalytic in manganese.
首次报道了锰催化的末端炔烃与芳基 C-H 烯烃化反应。该方法具有操作简单的特点，催化剂体系包含商业可得的 MnBr(CO)(5)和二环己基甲胺（Cy(2)NH）。该反应以高化学选择性、区域选择性和立体选择性方式进行，以高产率得到反式-Markovnikov 构型的 E-构型烯烃。实验研究和 DFT 计算揭示了：（1）反应通过锰和碱的协同作用，经 C-H 活化步骤引发；（2）锰内盐和炔基锰物种是关键的反应中间体；（3）配体到配体的 H 转移和炔基辅助的 C-H 活化是关键步骤，使反应在锰中具有催化性。
