Photo-induced stereo- and regiospecific sulfonylation of C–C multiple bonds exploiting the dual reactivity of sulfonium iodate(i) species

Abstract

Vinyl sulfones are privileged motifs for assembling prevalent biologically active molecules and represent “gateway functional groups” in medicinal chemistry and drug discovery. Expanding on our research on the bisfunctionalization of C–C multiple bonds, herein, we present a photo-induced (E)-stereospecific direct iodosulfonylation of alkynes and C(sp²)–H sulfonylation of alkenes by employing sulfonium iodate species. The scope and limitations of the atom-economical protocol were illustrated in detail with a broad range of structurally diverse substrates tolerating various sensitive moieties to access (E)-vinyl sulfones in a highly regioselective transformation. Mechanistic investigations involving radical/spin trapping control experiments and the isolation of an unprecedented BHT-tosyl adduct evidenced the photochemical radical sulfonylation with tosyl iodide generated in situ and discovered the intrinsic dual-reactivity of Me₃SI(OAc)₂ as an oxidant as well as the source of iodine.