Alkylation reactions are fundamental carbon-carbon bond-forming reactions in synthetic organic chemistry. Among them, intermolecular α-alkylation reactions of carbonyl compounds with alkenes are important because they are more atom-economical than the equivalent processes using alkyl halides. However, intermolecular reactions with nonactivated alkenes such as 1-hexene, which can allow the use of a wide range of valuable substrates, have been considered to be very challenging for a long time. In this review, radical-mediated intermolecular α-alkylation reactions of carbonyl compounds with nonactivated alkenes are discussed. The examples are grouped into three types of reactions: peroxide-mediated reactions, metal-oxidant-mediated reactions, and photoactivated reactions. Photoredox-catalyzed alkylation reactions under visible-light irradiation are discussed as a particularly promising recent hot topic. This review provides brief history and new prospects on the α-alkylation process with nonactivated alkenes using α-carbonyl radical species.

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羰基化合物与非活化烯烃的高效自由基介导的分子间 α-烷基化反应

烷基化反应是合成有机化学中基本的碳-碳键形成反应。其中，羰基化合物与烯烃的分子间α-烷基化反应非常重要，因为它们比使用烷基卤化物的等效方法更经济。然而，与非活化烯烃（例如1-己烯）的分子间反应可以使用多种有价值的底物，长期以来一直被认为是非常具有挑战性的。在这篇综述中，讨论了羰基化合物与非活化烯烃的自由基介导的分子间 α-烷基化反应。这些例子分为三种类型的反应：过氧化物介导的反应、金属氧化剂介导的反应和光活化反应。可见光照射下的光氧化还原催化的烷基化反应被认为是最近特别有前途的热门话题。本综述提供了使用 α-羰基自由基物种对非活化烯烃进行 α-烷基化过程的简要历史和新前景。