Metal- and Oxidant-Free Electrosynthesis of Heterocycles from 1,2-Diarylalkene Derivatives

Synthesis of heterocycles from 1,2-diarylalkene derivatives through electrosynthesis under metal- and oxidant-free conditions has been discovered. Cathodic reduction of 2-alkenylbenzoic acid or anodic oxidation of 2-alkenylbenzamide, 2-alkenylphenol and 2-alkenylaniline leads to the formation of reactive radical intermediates which afford corresponding phthalide, isochroman-1-one, isoindolin-1-one, benzofuran, and indole in satisfying yields with good functional group tolerance. Interestingly, different chemoselectivities were found in different reaction solvents. Several mechanistic investigations including cyclic voltammetry studies and control experiments were carried out to elucidate the reaction mechanisms.

Automated summary

The synthesis of heterocycles from 1,2-diarylalkene derivatives through electrosynthesis under metal- and oxidant-free conditions has been discovered. Reactive radical intermediates formed through cathodic reduction or anodic oxidation of specific compounds lead to the formation of various heterocyclic products with good functional group tolerance and high yields. Solvent-dependent chemoselectivity was observed, and mechanistic investigations helped elucidate the reaction mechanisms.