Copper-Catalyzed Regioselective Cleavage of C-X and C-H Bonds: A Strategy for Sulfur Dioxide Fixation.

The first example of direct fixation of sulfur dioxide between heteroaryls and aryl halides has been developed via copper-catalyzed regioselective cleavage of C-X and C-H bonds under base-free and ligand-free conditions by using DABSO (1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide)) as a solid and bench-stable sulfur dioxide surrogate. This mild protocol results in double C-S bond-forming reactions from simple precursors in the absence of prefunctionalized organometallic reagents, arenediazonium salts, and iodonium salts which extends the still limited number of sulfur dioxide fixation strategies.