Rhodium(III)-Catalyzed Redox-Neutral 1,1-Cyclization of N‑Methoxy Benzamides with Maleimides via C–H/N–H/N–O Activation: Detailed Mechanistic Investigation

An Rh­(III)-catalyzed 1,1-cyclization of N-methoxy benzamides with maleimides providing isoindolinone spirosuccinimides through N–H/C–H/N–O bond activation is described. The detailed mechanistic investigation including isolation of key metalacycle intermediate, deuterium labeling studies, and DFT calculations were performed. The computational study reveals that the AcOH that formed in the reaction medium plays a key role in the N–OMe bond cleavage and the oxidation of Rh­(I) to Rh­(III).

本研究报道了一例三价铑（Rh(III)）催化的N-甲氧基苯甲酰胺与马来酰亚胺的1,1-环化反应，该反应通过N-H/C-H/N-O键活化策略构建异吲哚啉酮螺琥珀酰亚胺类化合物。研究开展了详尽的机理探究工作，包括关键金属环中间体的分离、氘标记实验以及密度泛函理论（DFT）计算。计算研究表明，反应介质中生成的乙酸（AcOH）在N-OMe键断裂以及一价铑（Rh(I)）氧化为三价铑（Rh(III)）的过程中发挥关键作用。