Mechanistic Study in Click Reactions by Using (<i>N</i>-Heterocyclic carbene)Copper(I) Complexes: Anionic Effects
作者:Yi-Chen Lin、Yen-Jen Chen、Tzung-Yu Shih、Yu-Hsieh Chen、Yi-Chun Lai、Michael Y. Chiang、Gopal Chandru Senadi、Hsing-Yin Chen、Hsuan-Ying Chen
DOI:10.1021/acs.organomet.8b00565
日期:2019.1.28
deprotonation. Then, the six-membered metallacycle from the cycloadditions of methyl azide with mononuclear copper acetylide reacted with the second copper catalyst, (NHC)CuX, to form the dinuclear intermediate, which in turn underwent a rapid ring contraction to form another more stable dinuclear intermediate. After the protonation by neighboring NHC–H+, triazole was produced, and two (NHC)CuX catalysts were
合成了一系列带有N-杂环卡宾的Cu配合物,并研究了它们在铜催化的叠氮化物-炔烃环加成反应中的应用。催化结果表明,[L 2 Cu] Br表现出最大的活性,其他配合物的趋势为I> Br> Cl〜BF 4 > PF 6。在1LCuCl和苯乙炔的反应的1 H NMR谱表明,NHC配体从Cu原子上解离,使苯乙炔去质子化,生成苯乙炔。电导率研究也证明了这一现象。根据密度泛函理论计算,提出了NHC配体离解和苯乙炔去质子化后形成乙炔卤化铜的机理。然后,由叠氮化物与单核乙酰基铜的环加成反应生成的六元金属环与第二种铜催化剂(NHC)CuX反应,形成双核中间产物,该双核中间产物又经历了快速的环收缩,从而形成了另一种更稳定的双核中间产物。由邻近的NHC–H +质子化后制备了三唑,并回收了两种(NHC)CuX催化剂。