Synthesis of o-Aryloxy Triarylsulfonium Salts via Aryne Insertion into Diaryl Sulfoxides.

The aryne insertion into "S═O" bond has been validated recently. This technology is elusively applied to the synthesis of thioethers. In contrast to the reported cases, the reaction described furnished o-aryloxy triarylsulfonium salts, in lieu of thioethers, in good to excellent yields. The reaction is also featured by its exquisite regioselectivity, broad substrate scope, and mild conditions (25 °C). Preliminary mechanistic studies suggest that the reaction probably proceeds in a sequential [2 + 2] cycloaddtion/O-arylation/protonation pathway.