Synthesis of Vinyl and 1,3-Dienyl Sulfones Enabled by Photochemical Excitation of Halogen-Bonding Complexes

Abstract

The photochemical catalyst-free radical-based synthesis of vinyl and 1,3-dienyl sulfones is disclosed. Mechanistic investigations support that the transformations rely on a visible-light-promoted activation of a halogen-bonding complex, which is formed between an alkenyl (or 1,3-dienyl) bromide and a sodium sulfinate salt. The reactions exhibit a wide functional group tolerance (compatible with heteroatoms, electron-withdrawing and electron-donating groups), finding application in the structural modification of biologically relevant molecules. Eventually, a continuous flow protocol was developed to upscale these transformations.