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

Abstract

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).

Rhodium(III)‐Catalyzed Oxidative C(sp3)−H Alkenylation of 8‐Methylquinolines with Maleimides Under Aerobic Conditions

“…With the development of C−H functionalization, maleimides have been directly employed to couple with C(sp 2 )−H bond providing the Heck‐type product by means of transition metal catalysts . For instance, Prabhu reported a carboxylate group assisted Rh(III)‐catalyzed C(sp 2 )−H activation with maleimides leading to the decarboxylative Heck‐type products . Jeganmohan's group also disclosed a Rh(III)‐catalyzed ortho‐alkenylation of anilides with maleimides providing a Heck‐type product as the main product .…”

Isoindolinone Synthesis via One‐Pot Type Transition Metal Catalyzed C−C Bond Forming Reactions

“…The sulfonyl fluoride group can be readily utilized for example in a sulfur(VI) fluoride exchange reaction, which is a type of click reaction. Jeganmohan [37] conveyed their previous work with cobalt catalyzed isoindolinone synthesis (vide infra) to similar Rh III catalyzed method. Using maleimides as substrates with N ‐methoxy‐benzamides, 3‐spirosubstituted isoindolinones were produced in a facile manner (Scheme 8 B).…”

Transition metal-catalyzed coupling of heterocyclic alkenesviaC–H functionalization: recent trends and applications

“…128 The use of N-O oxidizing group directed C-H activation and 1,1 cyclization has been demonstrated for the coupling with N-methoxy benzamides (Scheme 86B). 129 Various functional groups tolerate the reaction, though a sterically encumbered substrate shows less reactivity. Interestingly, the reaction of 2-thienyl benzamide furnishes the alkenylated product instead of a cyclized one.…”