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  • Perry, Ian B; Brewer, Thomas F; Sarver, Patrick J; Schultz, Danielle M; DiRocco, Daniel A; MacMillan, David W C

    Nature (London), 08/2018, Letnik: 560, Številka: 7716
    Journal Article

    Despite the widespread success of transition-metal-catalysed cross-coupling methodologies, considerable limitations still exist in reactions at sp -hybridized carbon atoms, with most approaches relying on prefunctionalized alkylmetal or bromide coupling partners . Although the use of native functional groups (for example, carboxylic acids, alkenes and alcohols) has improved the overall efficiency of such transformations by expanding the range of potential feedstocks , the direct functionalization of carbon-hydrogen (C-H) bonds-the most abundant moiety in organic molecules-represents a more ideal approach to molecular construction. In recent years, an impressive range of reactions that form C(sp )-heteroatom bonds from strong C-H bonds has been reported . Additionally, valuable technologies have been developed for the formation of carbon-carbon bonds from the corresponding C(sp )-H bonds via substrate-directed transition-metal C-H insertion , undirected C-H insertion by captodative rhodium carbenoid complexes , or hydrogen atom transfer from weak, hydridic C-H bonds by electrophilic open-shell species . Despite these advances, a mild and general platform for the coupling of strong, neutral C(sp )-H bonds with aryl electrophiles has not been realized. Here we describe a protocol for the direct C(sp ) arylation of a diverse set of aliphatic, C-H bond-containing organic frameworks through the combination of light-driven, polyoxometalate-facilitated hydrogen atom transfer and nickel catalysis. This dual-catalytic manifold enables the generation of carbon-centred radicals from strong, neutral C-H bonds, which thereafter act as nucleophiles in nickel-mediated cross-coupling with aryl bromides to afford C(sp )-C(sp ) cross-coupled products. This technology enables unprecedented, single-step access to a broad array of complex, medicinally relevant molecules directly from natural products and chemical feedstocks through functionalization at sites that are unreactive under traditional methods.