Nickel-Catalyzed\nPhotoredox Allenylation of Alkyl\nHalides

We report a dual Ni/photoredox-catalyzed cross-coupling\nmethod\nfor propargyl carbonates and nonactivated alkyl bromides, facilitating\nthe synthesis of a variety of substituted allenes under mild and practical\nconditions. Mechanistically, the reaction integrates Ni-catalyzed\nactivation of the propargyl electrophile via S<sub>N</sub><sup>2</sup>′ oxidative addition at Ni(I) with silyl radical-induced activation\nof the alkyl halide through halogen-atom transfer. This methodology\nprovides a gentle approach for introducing allenyl groups into complex\nhalogenated aliphatic molecules, offering further opportunities for\nderivatization.