Radical‑Mediated Formal Anti‑Markovnikov Hydroalkenylation of Unactivated Alkenes Enabled by a Functional Alkenyl‑Radical Surrogate Strategy

Although alkenyl radicals are conceptually desirable for anti‑Markovnikov hydroalkenylation, their direct addition to unactivated alkenes is kinetically inaccessible owing to their intrinsically low electrophilicity and competing strong hydrogen atom abstraction reactivity. Herein, we establish a novel strategy to realize the first radical‑mediated formal anti‑Markovnikov hydroalkenylation of unactivated alkenes. This approach utilizes the combination of highly electrophilic triphenylphosphonium methyl (TPPM) radicals with weak H atom abstraction reactivity and carbonyl compounds as practical alkenyl‑radical surrogates. The transformation begins with the photocatalytic reduction of bromomethyl triphenylphosphonium bromide to generate TPPM radicals, which add to unactivated alkenes to form carbon-centered radicals that abstract a hydrogen atom from thiophenol. The resulting phosphonium salts subsequently undergo an in‑situ Wittig reaction with carbonyl compounds to furnish the devised hydroalkenylation products. This protocol exhibits good functional group tolerance, broad substrate scope covering both activated and unactivated olefins, and allows late‑stage functionalization of natural product derivatives.