Hydrodimerization of Unactivated α-Alkenes to Forge C(sp3)‒C(sp3) Bonds

Head-to-head hydrodimerization (HHD) of α-olefins has remained a long-standing challenge in organic synthesis. Herein we present a Ni-catalyzed protocol that enables effective HHD of a wide range of unactivated linear and sterically congested α-olefins to afford linear alkyl‒alkyl products in good yields and high linear/branched (L/B) ratios. The key aspect of our method is the use CuBr2/DTBP as co-oxidants that likely convert the initial dialkyl‒Ni(II) to the corresponding Ni(III) species, thus avoiding decomposition of the thermally labile dialkyl‒Ni(II) intermediate and promoting the formation of HHD products via more favored reductive elimination of the Ni(III) complex. This work offers a new avenue for constructing linear C(sp3)‒C(sp3) bonds via the direct connection of two α-alkenes.