Photooxygenation of Azidoalkyl Furans: Catalyst-Free Triazole and New Endoperoxide Rearrangement

Photooxygenation of azidoalkyl furans has revealed both a novel triazole formation method and a unique endoperoxide rearrangement. The key step of this method is a 3 + 2 cycloaddion of the azide to the endoperoxide intermediate. The reduction of the peroxide bond and two subsequent C–C bond cleavages provide a triazole having a newly formed carboxylic acid functionality. The reactions are clean and efficient with yields ranging from 60% to 90%.