Millisecond Aliphatic Iodonium‐Claisen Rearrangement Enabling Dual Functionalization of Alkenyl Iodanes

, TMSOAc, and phenols, thereby expanding the structural diversity of accessible products. Beyond furnishing conventional rearrangement products, the rearrangement intermediates can be intercepted intra- or intermolecularly by diverse carbon- and heteroatom-based nucleophiles, enabling dual functionalization of alkenyl iodanes. Mechanistic studies rationalize the unusually rapid kinetics of the rearrangement and reveal a pronounced trans influence exerted by the hypervalent iodine center, which not only governs the assembly of reactive partners but also facilitates the rearrangement.