Transition-Metal-Catalyzed Transformation of Sulfonates via S-O Bond Cleavage: Synthesis of Alkyl Aryl Ether and Diaryl Ether.

The catalytic conversion of sulfonates, a versatile class of pharmaceutical intermediates, is usually based on C-O bond cleavage. In this paper, however, we discover a rare transformation of sulfonates via S-O bond cleavage catalyzed by transition metal, through which alkyl sulfonates could undergo an intramolecular desulfitative C-O coupling to form aryl alkyl ethers in the presence of a nickel catalyst. Meanwhile, aryl sulfonates perform similarly to give diaryl ethers catalyzed by a palladium complex. This transformation could tolerate a wide range of functionalities. Controlled experiments reveal that the 2-pyridyl group is necessary to promote the reaction as designed. Crossover experiments proved that this transformation might proceed partly in an intermolecular pathway.