Development of visible light-mediated atom transfer radical addition of haloalkanes onto unsaturated hydrocarbons has seen rapid growth in recent years. However, due to its radical chain propagation mechanism, diverse functionality other than the pre-existing (pseudo-)halide on the alkyl halide source cannot be incorporated into target molecules in a one-step, economic fashion. Inspired by the prominent reactivities shown by cytochrome P450 hydroxylase and non-heme iron-dependent oxygenases, we herein report the first modular, dual catalytic difunctionalization of unactivated alkenes via manganese-catalyzed radical ligand transfer (RLT). This RLT elementary step involves a coordinated nucleophile rebounding to a carbon-centered radical to form a new C–X bond in analogy to the radical rebound step in metalloenzymes. The protocol leverages the synergetic cooperation of both a photocatalyst and earth-abundant manganese complex to deliver two radical species in succession to minimally functionalized alkenes, enabling modular diversification of the radical intermediate by a high-valent manganese species capable of delivering various external nucleophiles. A broad scope (97 examples, including drugs/natural product motifs), mild conditions, and excellent chemoselectivity were shown for a variety of substrates and fluoroalkyl fragments. Mechanistic and kinetics studies provide insights into the radical nature of the dual catalytic transformation and support radical ligand transfer (RLT) as a new strategy to deliver diverse functionality selectively to carbon-centered radicals.

中文翻译：

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通过仿生自由基配体转移催化对未活化烯烃进行模块化双官能化

近年来，卤代烷在不饱和烃上的可见光介导原子转移自由基加成技术发展迅速。然而，由于其自​​由基链增长机制，除了烷基卤源上预先存在的（假）卤化物之外的多种功能不能以一步经济的方式结合到目标分子中。受细胞色素 P450 羟化酶和非血红素铁依赖性加氧酶所显示的突出反应性的启发，我们在此报告了通过锰催化自由基配体转移 (RLT) 对未活化烯烃进行的第一个模块化、双重催化双功能化。该 RLT 基本步骤涉及配位的亲核试剂反弹至碳中心自由基以形成新的 C-X 键，类似于金属酶中的自由基反弹步骤。该协议利用光催化剂和富含地球的锰复合物的协同合作，将两种自由基物质连续输送到最小功能化的烯烃，从而通过能够输送各种外部亲核试剂的高价锰物质实现自由基中间体的模块化多样化。对各种底物和氟烷基片段显示了广泛的范围（97 个示例，包括药物/天然产物基序）、温和的条件和出色的化学选择性。机理和动力学研究提供了对双重催化转化的自由基性质的见解，并支持自由基配体转移 (RLT) 作为一种新策略，可选择性地向碳中心自由基提供多种功能。