Photo-redox catalyzed dehydrazinative acylation of N-heterocycles via Minisci reaction

Abstract

Visible light-induced acylation of heteroaromatic compounds have been achieved using benzoyl hydrazides as an efficient acyl source under mild reaction conditions.

Advances in Photoinduced Minisci-like Reactions

“…The acylation of electron-poor N -heterocycles was accomplished using benzoyl hydrazides as acyl radical precursors. 53 The proposed mechanism involves the excitation of eosin Y with white light and the quenching of its photoexcited state by persulfate, forming the sulfate radical anion. Releasing hydrogen gas, nitrogen gas, and the desired acyl radical accompanies a HAT between this and the hydrazide.…”

BPO-promoted [4 + 2] cyclization of enaminones and o-phenylenediamines to 2-acyl quinoxalines via a cascade transamination and C–H amination

“…11 Later on, the same group realized the nickel-catalyzed electrochemical Minisci acylation of quinoxalines via a ligand-to-metal electron transfer pathway. 12 Besides, other work using benzaldehydes, 13 benzoyl chlorides, 14 phenylacetylenes, 15 benzoyl hydrazines, 16 and benzylamines 17 as acyl radical precursors, has also been reported. Despite these outstanding works, the exploration of conceptually distinct strategies is obviously still an urgent issue.…”

“…9 Thus, the development of highly efficient strategies for accessing 2-acyl quinoxalines has attracted much attention from the synthetic community. [10][11][12][13][14][15][16][17] General approaches for the direct construction of such architectures mainly focused on Minisci acylation of quinoxalines, which are pre-prepared from o-phenyle-nediamines and oxalaldehyde (Scheme 1b). For example, Zeng's group have reported the electrochemical Minisci acylation of quinoxalines using α-keto acids as acyl radical precursors and NH 4 I as a redox catalyst.…”

Electrochemical Decarboxylative Minisci-Type Acylation of Quinoxalines under Catalyst- and External-Oxidant-Free Conditions

“…TBHP, K2S2O8 et al) under thermal and photocatalytic conditions. 4,5 From the sustainability viewpoint, the development of a Minisci-type acylation reaction under catalyst-and external oxidant-free conditions is highly desirable but remains a challenge.…”