The electrochemical oxidative cross-coupling represents one of the most atomic economic and green approaches to synthesize various useful compounds. In this work, an electrochemical C3-sulfonylation of imidazo[1, 2-a]pyridines with sodium...

The C3-functionalized imidazo­[1,2-a]­pyridines are versatile nitrogen-fused heterocycles; however, the methods for the C3 acyloxylation of imidazo­[1,2-a]­pyridines have never been reported. Herein we demonstrate the electrochemical oxidative C3 acyloxylation of imidazo­[1,2-a]­pyridines for the first time. Notably, by using electricity, the electrochemical oxidative C3 acyloxylation of imidazo­[1,2-a]­pyridines was carried out under mild conditions. Moreover, in addition to aromatic carboxylic acids, alkyl carboxylic acids were also competent substrates.

1,3,4‐Oxadiazoles are a kind of useful heterocycles which can be frequently found in materials and bioactive molecules. In this study, intermolecular electrochemical cyclization between α‐keto acids and acylhydrazines has been developed for the synthesis of 2,5‐disubstituted 1,3,4‐oxadiazoles with the yield up to 91 %. This transformation can be run under mild reaction conditions in the absence of external oxidant, base and transition metal catalyst. Both symmetrical and unsymmetrical 2,5‐disubstituted 1,3,4‐oxadiazoles could be prepared according to the careful choice of the substrate combination. Gram scale synthesis also illustrates the potential application of this protocol in large preparation.

An electrochemical oxidative cross-coupling reaction between 2.5-substituted-pyrazolin-5-ones and ammonium thiocyanate has been developed.

An electrochemical oxidative C(sp 2)-H sulfuration has been developed. Various enaminones and thiophenols were compatible, generating the desired alkenyl sulfur compounds in up to 87 % yield. This transformation proceeded smoothly under mild reaction conditions without external oxidant and transition-metal catalyst. Remarkably, thiophenols selectively coupled with enamines when substrates had other alkenyl groups. In addition, the desired products could be further transformed into a series of αsulfur isoxazoles, which are a kind of useful heterocycles in materials and bioactive molecules.