Efficient phenolic oxidations using μ-oxo-bridged phenyliodine trifluoroacetate

The excellent oxidizing behavior of the μ-oxo-bridged phenyliodine trifluoroacetate 1 is revealed during the phenolic oxidations mediated by hypervalent iodine(III) reagents. The use of the μ-oxo-bridged compound 1 instead of PhI(OAc)2 (PIDA) and PhI(OCOCF3)2 (PIFA) during the oxidative cyclization of phenols involving carbon–oxygen, carbon–nitrogen, and carbon–carbon bond formations could produce spirocyclized cyclohexadienones in comparable or somewhat better yields. Thus, we have concluded that the unique reagent 1 is a promising alternative to PIDA and PIFA, and the use of reagent 1 as a reasonable choice is recommended for the hypervalent iodine(III)-mediated phenolic oxidations as well as other transformations.