Photoinduced Ligated Boryl Radical-Mediated Alkynylation of Inert Iodoalkanes

In this study, we report a metal-free C(sp3)–C(sp)
cross-coupling reaction between chemically inert alkyl iodides and
arylacetylene bromides. This transformation utilizes bench-stable,
ligated boranes as a halogen atom transfer (XAT) reagent to activate
various alkyl iodides. The mild and straightforward reaction conditions
enable the efficient synthesis of a broad array of substituted alkynes,
accommodating diverse functional groups. Furthermore, the synthetic
utility of the method has been showcased through the successful late-stage
alkynylation of several pharmaceutically relevant molecules. Preliminary
mechanistic investigations indicate that the transformation proceeds
via a radical pathway.