A Three-Component\nReaction\nof Alkenyl Thianthrenium\nSalts, Cyclopropanols and Sulfur Dioxide

A three-component\nreaction of alkenyl thianthrenium salts, cyclopropan-1-ols\nand DABCO·(SO<sub>2</sub>)<sub>2</sub> under catalyst- and additive-free\nconditions, is accomplished. This sulfonylation with the insertion\nof sulfur dioxide works efficiently under very mild conditions, leading\nto a wide range of 1-substituted vinyl sulfones in moderate to good\nyields. In this protocol, the scope generality of alkenyl thianthrenium\nsalts and cyclopropyl alcohols is demonstrated.