Copper-Catalyzed Difunctionalization of Allenes with Sulfonyl Iodides Leading to ( E)-α-Iodomethyl Vinylsulfones.

A highly regioselective iodosulfonylation of allenes in the presence of CuI and 1,10-phenanthroline has been developed for the synthesis of various useful ( E)-α-iodomethyl vinylsulfones in moderate to excellent yields. This practical reaction is fast, operationally simple, and in particular, proceeds under very mild conditions to afford the target products with high regio- and stereoselectivity. The selectivity was illustrated by a conceptual DFT analysis.