Recent advances in the sulfonylation of C-H bonds with the insertion of sulfur dioxide.

Recent advances in the sulfonylation of C-H bonds with the insertion of sulfur dioxide are summarized. Usually, a sulfur dioxide surrogate, DABCO·(SO2)2, is used, which avoids the utilization of gaseous sulfur dioxide in the transformation. Inorganic sulfites such as sodium metabisulfite are also effective in C(sp3)-H bond sulfonylation. C-H bond sulfonylation under transition metal catalysis or through a radical process has been developed. In some cases, the sulfonylation can be performed under catalyst- and additive-free conditions, or can be facilitated by visible light irradiation. The efficiency is also investigated by merging the radical process and metal catalysis.