C–H Activation Relay (CHAR): An Efficient Construction of Isatin Skeleton by Aerobic Oxidation of Glycine Esters

Abstract

Directed by the strategy of C−H activation relay (CHAR), an efficient construction of isatin skeleton was developed through catalytic oxidation of glycine esters. The mechanistic study reveals that the oxidation of the relatively active C−H bonds initiated the followed activation of remote and inert C−H bonds, and an intramolecular 1,6-hydrogen shift was involved as a key step.

A Consecutive C−H Functionalization Triggered by Oxidation of Active sp3 C−H Bonds: Construction of 3,4‐Dihydroquinoline‐3‐one Derivatives

“…In 2016, we designed and achieved an efficient construction of the isatin skeleton by a strategy named C−H activation relay (CHAR), in which the oxidation of active sp 3 C−H bonds provokes further activation of C−H and C−O bonds in an ester group by intramolecular hydrogen atom abstraction (Figure , Eq. 1) . This reaction suggests the possibility that generation of a radical intermediate on an active position might be a handle to achieve efficient and selective activation of inert C−H bonds by a free‐radical process.…”

Auto‐Oxidation‐Induced Construction of Isatins from Glycine Derivatives

“…Based on the above control experiments and previous references, [13] we propose a plausible mechanism for this cascade reaction, taking methyl 2-(methyl(p-tolyl)amino)acetate 1 a as model substrate (Scheme 6). First, a hydrogen atom is abstracted from glycine ester 1 a to O 2 through single electron transfer process, which generates a highly reactive radical intermediate A.…”

Recent Advances for Synthesis of Oxazole Heterocycles via C‐H/C‐N Bond Functionalization of Benzylamines

“…At last, the oxidation of intermediate 170 affords the anticipated product 166 (path a) [64] . Instead, a SET/deprotonation process gives intermediate 171 (pathway b) from the intermediate 168 , which further affords intermediate 172 [65,66] . Finally, the cyclization of intermediate 172 into 173 proceeds towards the formation of final product via SET/deprotonation process (path b).…”