Mechanistic DFT Study on Rhodium(III)‐Catalyzed Double C−H Activation for Oxidative Annulations of 2‐Substituted Imidazoles and Alkynes

Abstract

Am echanistic understanding of the rhodium(III)catalyzed doubleC ÀHa ctivation for oxidative annulations of 2-substituted imidazoles and alkynes was achieved by density functional theory calculations. It is disclosed that the rhodium(III)-acetate-triggered CÀHb ond cleavage occurs with-out ad irecting group, and the C5ÀHc leavage has the lowest activation barriera mong all possible CÀHa ctivation processes.T he experimental observationsi nr eactions of different imidazole derivatives were explained well by the theoretical results.Scheme1.Strategies for transition-metal-catalyzed CÀHa ctivation. DG = directing group, Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl.

Ruthenium(II)-Catalyzed Homocoupling of α-Carbonyl Sulfoxonium Ylides Under Mild Conditions: Methodology Development and Mechanistic DFT Study

“…It was generally proposed that the cyclic product was formed by the first generation of an acylmethylation intermediate in similar cascade reactions. (Chen et al, 2018;Hu et al, 2018aHu et al, ,b, 2019Liang et al, 2018;Shi et al, 2018;Xiao et al, 2018;Xie et al, 2018bXie et al, , 2019Xie H. et al, 2018;Xu et al, 2018;Zhou et al, 2018;Cai et al, 2019;Chen P. et al, 2019;Cui et al, 2019;Huang et al, 2019;Lai et al, 2019;Liu et al, 2019;Luo et al, 2019;Lv et al, 2019;Nie et al, 2019;Shen et al, 2019;Wu C. et al, 2019;Zhang et al, 2019Zhang et al, , 2020Wu et al, 2020). Further transformations from IM6 were explored theoretically to confirm whether the acylmethylation intermediate (IM8) is key in the formation of 2a (Figure 2).…”

C–H activation-annulation on the N-heterocyclic carbene platform

“…Undoubtedly, this work motivated others to explore other annulative transformations and mechanistic investigations too. 28 …”