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

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. O-18 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.

Automated summary

Here, we developed an environmentally friendly electrooxidative method for the synthesis of indolizines substituted with various formyl and acyl groups. This method allows for the sequential formation of C-N and C-O bonds, and has good yields. It utilizes sub-equivalent amounts of iodide salts as the redox mediator, and shows broad substrate scope, excellent functional group tolerance, and eliminates the need for oxidizing reagents.