Electrochemically-initiated intramolecular 1,2-amino oxygenation of alkynes: facile access to formyl- and acyl-substituted indolizines

Abstract

Here, an environmentally benign electrooxidative approach to the intramolecular aminooxygenation of alkynes has been developed. The method allows for the rapid assembly of diverse formyl- and acyl-substituted indolizines in good to excellent yields through the sequential formation of C–N and C–O bonds. This electrosynthesis employs sub-equivalent amounts of iodide salts as the redox mediator, has broad substrate scope and excellent functional group tolerance, and obviates the need for oxidizing reagents. ¹⁸O isotope tracing confirmed that the oxygen atom of the carbonyl group was derived from water. The synthetic usefulness of this electrosynthetic protocol was further demonstrated by its easy scalability and diverse transformations of electrolysis products.