Organometallic reagents are routinely used as fundamental building blocks in organic chemistry to rapidly diversify molecular fragments via carbanion intermediates. However, the catalytic generation of carbanion equivalents, particularly from sp³-hybridized alkyl scaffolds, remains an underdeveloped goal in chemical synthesis. Here we disclose an approach for the generation of alkyl carbanions via single-electron reduction of aryl alkenes, enabled by multi-photon photoredox catalysis. We demonstrate that photocatalytically induced alkyl carbanions engage in intermolecular C–C bond-forming reactions with carbonyl electrophiles. Central to this method is the controlled formation of an alkene distonic radical anion intermediate that undergoes nucleophilic addition, followed by a kinetically favoured reductive polar crossover to produce a second carbanion available for further diversification. The versatility of this protocol was illustrated by the development of four distinct intermolecular C–C bond-forming reactions with aromatic alkenes (hydroalkoxylation, hydroamidation, aminoalkylation and carboxyaminoalkylation) to generate a range of valuable and complex scaffolds.

有机金属试剂通常用作有机化学的基本组成部分，通过碳负离子中间体快速使分子片段多样化。然而，催化生成碳负离子当量，特别是从 sp³ 杂化烷基支架中产生，仍然是化学合成中一个不成熟的目标。在这里，我们揭示了一种通过多光子光氧化还原催化实现芳基烯烃的单电子还原生成烷基碳化物的方法。我们证明光催化诱导的烷基碳负离子与羰基亲电试剂进行分子间 C-C 键形成反应。该方法的核心是烯烃二硝基自由基阴离子中间体的受控形成，该中间体经过亲核加成，然后进行动力学上有利的还原极叉，以产生可用于进一步多样化的第二碳负离子。该方案的多功能性通过与芳香族烯烃（氢烷氧基化、加氢酰胺化、氨基烷基化和羧基氨基烷基化）的四种不同的分子间 C-C 键形成反应的发展来说明，以产生一系列有价值且复杂的支架。