Pd-Catalyzed Conversion of Alkynyl‑λ3‑iodanes to Alkenyl‑λ3‑iodanes via Stereoselective 1,2-Iodine(III) Shift/1,1-Hydrocarboxylation

Alkynyl-λ3-iodanes have been established as alkynyl cation equivalents for the alkynylation of carbon- and heteroatom-based nucleophiles. Herein, we report an unprecedented reaction mode of this compound class, which features a Pd­(II)-assisted 1,2-I­(III) shift of an alkynylbenziodoxole. A Pd­(II) catalyst mediates this shift and the subsequent interception of the transient vinylidene species with carboxylic acid (1,1-hydro­carboxylation). The product of this stereoselective rearrangement–addition reaction, β-oxyalkenyl­benziodoxole, represents a novel and useful building block for further synthetic transformations.