Oxidative C-H Sulfonylation of Hydrazones Enabled by Electrochemistry

An efficient electrochemical oxidative C(sp(2))-H sulfonyla-tion of aldehyde hydrazones is described. A variety of sodium sufinates or sulfinic acids participate effectively in this protocol, which provides facile access to an array of alkyl and aromatic sulfonylated hydrazones with up to 96% yield. Large-scale synthesis and product derivatization show the potential utility of this methodology. Preliminary mechanistic investigations including radical-inhibition, electricity on/off experiments, and cyclic voltammetry support a radical pathway.