The Reformatsky reaction has been examined using a mild and effective method of electrochemical zinc activation, based on the cathodic reduction of a catalytic amount of zinc bromide in acetonitrile.
Coupling reactions of α-chloroesters with aryl halides (α-arylation) or carbonyl compounds (Reformatsky) using nickel catalyst allow, under mild conditions, the preparation of various functionalized aryl propionic acid derivatives or β-hydroxyesters. In the synthesis of aryl propionic acid derivatives, the process is efficient with aryl halides bearing either electron-withdrawing or electron-donating
Metal exchange between an electrogenerated organonickel species and zinc halide: application to an electrochemical, nickel-catalyzed Reformatsky reaction
作者:Annie Conan、Soline Sibille、Jacques Perichon
DOI:10.1021/jo00006a012
日期:1991.3
The mechanism of the electroreductive coupling of alpha-chloro esters or alpha-chloro nitriles with carbonyl compounds by the means of a sacrificial zinc anode and a nickel catalyst was elucidated by electroanalytical techniques. The mechanism involved reduction of a Ni(II) complex to a Ni(0) complex, oxidative addition of the alpha-chloro ester to the Ni(0) complex, and a Zn(II)/Ni(II) exchange, leading to an organozinc Reformatsky reagent. The electrosynthesis of various beta-hydroxy esters, beta-hydroxy nitriles, and 2,3-epoxy esters was successfully achieved under extremely mild conditions.
Iron-Mediated Electrochemical Reaction of α-Chloroesters with Carbonyl Compounds
Reformatsky-type reactions have been performed efficiently using an electroassisted iron-complex catalysis. Valuable product such as beta-hydroxyesters, ketones or nitriles are thus prepared with high yields.