Electronickel-Catalyzed 1,5-Hydroarylation of Alkynyl Epoxides

Electrochemical transformations of epoxides have emerged as a useful platform for alcohol synthesis, and their reactivity and selectivity are strongly dictated by the substitutions of the epoxides. Incorporation of an alkynyl substituent into the epoxide framework offers a promising yet unexplored avenue toward highly functionalized different alcohol derivatives posing formidable challenges in selectivity control. Here, we report an earth-abundant metal of nickel-catalyzed cross-electrophile coupling between readily available alkynyl epoxides and aryl/alkenyl halides, enabling the highly selective synthesis of allenols under mild electrochemical conditions. This protocol exhibits a broad substrate scope, preferential C−O bond activation over C−X bonds, and a decent chemoselectivity for C−I activation over the C−Br bond, while tolerating a wide array of synthetically valuable functional groups, such as free hydroxyl, ketone, carboxylate, methoxy, TBS ether, N -Boc, highly strained cyclopropyl, C═C bonds, C−TMS, C−F bonds, C−Cl bonds, C−Br bonds, and even C−B bonds. Moreover, this methodology may also apply to the synthesis of allenols bearing pharmaceutical and biologically active moieties, and the downstream derivatizations of allenol products have also been realized, offering a modular platform for the synthesis of diversified functional structures.