Ketyl–olefin coupling reactions stand as one of the fundamental chemical transformations in synthetic chemistry and have been widely employed in the generation of complex molecular architectures and natural product synthesis. However, catalytic ketyl–olefin coupling, until the recent development of photoredox chemistry and electrosynthesis through single-electron transfer mechanisms, has remained largely undeveloped. Herein, we describe a new approach to achieve catalytic ketyl–olefin coupling reactions by a halogen-atom transfer mechanism, which provides innovative and efficient access to various gem-difluorohomoallylic alcohols under mild conditions with broad substrate scope. Preliminary mechanistic experimental and computational studies demonstrate that this radical-to-polar crossover transformation could be achieved by sequentially orchestrated Lewis acid activation, halogen-atom transfer, radical addition, single-electron reduction and β-fluoro elimination.

中文翻译：

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卤原子转移催化脱氟酮基-烯烃偶联

酮基-烯烃偶联反应是合成化学中的基本化学转化之一，已广泛用于复杂分子结构的生成和天然产物的合成。然而，催化酮基-烯烃偶联，直到最近通过单电子转移机制发展出光氧化还原化学和电合成，在很大程度上仍未得到发展。在这里，我们描述了一种通过卤原子转移机制实现催化酮基-烯烃偶联反应的新方法，它为各种宝石​​提供了创新和有效的途径-在温和条件下具有广泛底物范围的二氟高烯丙醇。初步的机械实验和计算研究表明，这种自由基到极性的交叉转变可以通过顺序协调的路易斯酸活化、卤素原子转移、自由基加成、单电子还原和 β-氟消除来实现。