Halonium-Initiated C–O Bond Formation via Umpolung of α-Carbon to the Carbonyl: Efficient Access to 5-Amino-3(2H)-furanones

Highly efficient C–O bond formation has been developed via carboxylic acid catalyzed reaction of 1-acetylcyclopropanecarboxamides with N-halosuccinimide (NXS), which provides strategically novel and atom-economic access to biologically important 5-amino-3(2H)-furanones. The mechanism of halonium-initiated tandem oxa-cyclization and ring opening of cyclopropane was proposed. A variety of nucleophiles were found to open the cyclopropane.