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.