Despite the fundamental importance of efficient and selective synthesis of widely useful alkylarenes, the direct catalytic C(sp²)–H alkylation of unactivated arenes with a readily available alkyl halide remains elusive. Here, we report the catalytic C(sp²)–H alkylation reactions of unactivated arenes with alkyl bromides via visible-light induced Pd catalysis. The reaction proceeds smoothly under mild conditions without any skeletal rearrangement of the alkyl groups. The direct syntheses of structurally diverse linear and branched alkylarenes, including the late-stage phenylation of biologically active molecules and an orthogonal one-pot sequential Pd-catalyzed C–C bond-forming reaction, are achieved with exclusive chemoselectivity and exceptional functional group tolerance. Comprehensive mechanistic investigations through a combination of experimental and computational methods reveal a distinguishable Pd(0)/Pd(I) redox catalytic cycle and the origin of the counter-intuitive reactivity differences among alkyl halides.

尽管高效和选择性合成广泛有用的烷基芳烃具有根本重要性，但用现成的卤代烷直接催化未活化芳烃的 C(sp ² )-H 烷基化仍然难以实现。在这里，我们报告了催化 C(sp ²)–通过可见光诱导的 Pd 催化未活化芳烃与烷基溴的 H 烷基化反应。反应在温和条件下顺利进行，烷基没有任何骨架重排。结构多样的直链和支链烷基芳烃的直接合成，包括生物活性分子的后期苯基化和正交一锅顺序 Pd 催化的 C-C 键形成反应，具有独特的化学选择性和出色的官能团耐受性。通过实验和计算方法相结合的综合机理研究揭示了可区分的 Pd(0)/Pd(I) 氧化还原催化循环以及烷基卤化物之间反直觉反应性差异的起源。