Dioxygen-Triggered Oxo-Sulfonylation of Hydrazones.

A simple and highly efficient method for the oxo-sulfonylation of aldehyde-derived hydrazones has been developed using sulfinic acid as a source of sulfonyl group and oxygen as a green oxidant under metal-free conditions at room temperature. The present C-O and N-S bond-forming difunctionalization strategy affords diversely functionalized N-acylsulfonamides in good yield. Experimental results suggest a radical mechanistic pathway of the present reaction.