One pot tandem dehydrogenative cross-coupling of primary and secondary alcohols by ruthenium amido-functionalized 1,2,4-triazole derived N-heterocyclic carbene complexes
作者:Anuj Kumar、Sabyasachi Ta、Chandrasekhar Nettem、Joseph M. Tanski、Gopalan Rajaraman、Prasenjit Ghosh
DOI:10.1039/d2ra05531g
日期:——
mechanism completely, and the mechanisms adapted are divided categorically into three steps (i) nucleophilic substitution of chloride ions by alcohols, (ii) dehydrogenation of primary and secondary alcohols, and (iii) olefin and ketone hydrogenation. Our mechanistic study reveals that the formation of a deprotonated Ru–alcoholate (A) or (E) intermediate is favorable compared to the protonated form (A′)
三个钌配合物[1-( R )-4- N- (呋喃-2-基甲基)乙酰胺基-1,2,4-三唑-5-亚基催化伯醇和仲醇的一锅串联脱氢交叉偶联反应]Ru( p-伞花烯)Cl [R = Et ( 1b ), i-Pr ( 2b ), Bn ( 3b )],是酰胺基官能化的 1,2,4-三唑衍生的 N-杂环卡宾 (NHC) 配体。对钌 ( 1b ) 预催化剂采用密度泛函理论 (DFT) 计算,以完全理解该反应机理,所采用的机理可分为三个步骤 (i) 氯离子被醇进行亲核取代,(ii) 伯脱氢和仲醇,以及(iii)烯烃和酮氢化。我们的机理研究表明,与 ( 1b ) 中通过缔合亲核取代形成的质子化形式 ( A' ) 或 ( E' ) 相比,去质子化的 Ru-醇化物 ( A ) 或 ( E ) 中间体的形成更有利。尽管通过 ( A' ) 或 ( E' ) 进行的离子途径在脱氢和烯烃/酮氢化步骤中的势垒比通过 (