Copper-Catalyzed Oxidative Cyclization of Alkynes with Sulfonylhydrazides Leading to 2-Sulfonated 9H-pyrrolo[1,2-a]indol-9-ones

A copper-catalyzed oxidative cyclization procedure has been developed for the production of 2-sulfonated 9H-pyrrolo[1,2-a]indol-9-ones via the direct sulfonylation of N-propargyl-substituted indoles with sulfonylhydrazides and tert-butyl hydroperoxide (TBHP). This novel protocol, which tolerates a broad range of functional groups, offers a simple, efficient, and atom-economical route to a series of fluorazones in good yields under mild conditions.