Dihaloiodoarenes: α,α-Dihalogenation of Phenylacetate Derivatives

A hypervalent iodine reagent-based α-carbonyl dihalogenation reaction is reported. Treating diazoacetate derivatives with either iodobenzene dichloride or iodotoluene difluoride results in <i>gem</i>-dichlorination or <i>gem</i>-difluorination products, respectively. The reaction is catalyzed by either Lewis acid or Lewis base activation of the aryl-λ³-iodane (ArIX₂) species and proceeds rapidly and chemoselectively to the desired <i>gem</i>-difunctionalized products in good to excellent yield