“Green” Oxidant (Oxygen) Mediated Synthesis of <i>N</i>-(2-(Methylsulfonyl)ethyl)amide Derivatives Using DMSO as a Dual Synthon and Solvent

Sulfone derivatives are important components of many pharmaceuticals. This Letter reports an efficient method for synthesizing N -(2-(methylsulfonyl)ethyl)amide compounds with sulfone skeletons from amide compounds and dimethyl sulfoxide (DMSO) using an environmentally benign oxidant (oxygen). This metal-free protocol features operational simplicity, a low-cost and nonhazardous oxidant mediator, good functional group tolerance, and scalability to gram-scale. Notably, DMSO acts as a dual synthon donor, providing both methylene (−CH 2 −) and methylsulfonyl (−SO 2 Me) groups to form C(sp 3 )–N and C(sp 3 )–C(sp 3 ) bonds while serving as the solvent. A radical mechanism is proposed based on control experiments and EPR spectroscopy.