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

ABSTRACT The evolution of Claisen rearrangements through expansion of the central atom from classical oxygen to sulfur, nitrogen, and phosphorus has reshaped the reaction manifold by redefining substrates, enabling new modes of selectivity control, and enriching product diversity. Here we report an aliphatic iodonium Claisen rearrangement of alkenyl iodanes with suitable nucleophiles. Substitution of the classic oxygen center by an iodine(III) moiety enables allyl alkenyl iodonium species to undergo rearrangement at −78 °C with completion in less than 0.1 s, while broadening the scope of rearrangement partners to include allyl/propargyl silanes, α‑stannyl nitriles, TMSN 3 , 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.