Selective Electrochemical Halogenation of Functionalized Quinolone

Abstract

This work describes an effective C3–H halogenation of quinoline-4(1H)-ones under electrochemical conditions, in which potassium halides serve as both halogenating agents and electrolytes. The protocol provides expedient access to different halogenated quinoline-4(1H)-ones with unique regioselectivity, broad substrate scope, and gram-scale synthesis employing convenient, environmentally friendly electrolysis, in an undivided cell. Mechanism studies have shown that halogen radicals can promote the activation of N–H bonds in quinolones.

Electrochemical oxidative selective halogenation of pyrazolones for the synthesis of 4-halopyrazolones

“…Based on the literature and our experimental results, 36,37 we propose a plausible reaction mechanism for the electrochemical oxidative selective halogenation of pyrazolones (Scheme 6). Firstly, the anodic oxidation of the bromide anion produces the corresponding bromide radical A .…”

“…21–27 In recent years, there have been significant breakthroughs in the field of electrochemical halogenation. 28–36 To our best knowledge, the electrochemical oxidative halogenation of pyrazolones remains uncharted territory. Herein, we present a halogenation of pyrazolones via organic electrosynthesis that is both highly efficient and selective (Scheme 1c).…”

A continuous flow electrochemical reactor using readily available metal wires and carbon fibers as electrodes: environmentally benign halogenations of alkenes, alkynes, and aromatics

“…31–39,40–48 And there has been much progress in electrochemical halogenation of alkenes, alkynes, and aromatics. 12–24 However, the use of flow-electrochemical halogenation is rare.…”

“…[31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] And there has been much progress in electrochemical halogenation of alkenes, alkynes, and aromatics. [12][13][14][15][16][17][18][19][20][21][22][23][24] However, the use of flow-electrochemical halogenation is rare.…”