Metal- and Base-Free C(sp2)-H Arylsulfonylation of Enamides for Synthesis of (E)-β-Amidovinyl Sulfones via the Insertion of Sulfur Dioxide

A metal- and base-free C(sp(2))-H direct arylsulfonylation of secondary and tertiary enamides with aryldiazonium salts and ex situ generated SO2 (from SOgen) is presented. This method runs smoothly to produce beta-amidovinyi sulfones with excellent stereoselectivities in moderate to excellent yields. Moreover, this strategy features good functional group tolerance and environmentally benign reaction conditions. Mechanistic experiments indicate that this sulfonylation may proceed in a radical pathway.

Automated summary

A metal- and base-free method for the C(sp(2))-H arylation of secondary and tertiary enamides with aryldiazonium salts and ex situ generated SO2 has been developed. This approach produces beta-amidovinyi sulfones with excellent stereoselectivities in moderate to excellent yields, showcasing good functional group tolerance and environmentally benign reaction conditions. Mechanistic experiments suggest that this sulfonylation proceeds via a radical pathway.