LAUSR

Hypervalent iodine (III) five-membered heterocycles have found broad application as atom-transfer reagents for organic synthesis. Among them, 1-Phenyl-1,2-benziodoxol-3-(1H)-one is known as a traditional benzyne precursor, but no further synthetic applications have been reported. Herein, we report the first synthetic application of 1-phenylbenzidoxole to the synthesis of Phthalides using only CuI as catalyst. High selectivity and yield were achieved under mild reaction conditions with good functional group tolerance. During our investigations, the efficiency of different CuI and CuII catalysts under various reaction conditions were studied. The nature of the leaving group, the substituents on the substrate and temperature, play an important role on both yield and selectivity. Moreover, a plausible mechanistic pathway for this transformation was proposed based on our observations and previous literature reports.