Glyoxylic Acid Monohydrate-Promoted Formation of the C-SO 2 Bond Starting from Maleimides/Quinones and Sodium Sulfinates.

By using glyoxylic acid monohydrate as a promoter, a wide range of substances containing a C-SO 2 bond could be obtained from N-substituted maleimides or quinones and sodium sulfinates. The protocol features mild reaction conditions, short reaction time, and good atomic economics, which provides an alternative protocol for the α- sulfonylation of α,β-unsaturated ketones.