Although the α-alkylation of ketones has already been established, the analogous reaction using aldehyde substrates has proven surprisingly elusive. Despite the structural similarities between the two classes of compounds, the sensitivity and unique reactivity of the aldehyde functionality has typically required activated substrates or specialized additives. Here, we show that the synergistic merger of three catalytic processes—photoredox, enamine and hydrogen-atom transfer (HAT) catalysis—enables an enantioselective α-aldehyde alkylation reaction that employs simple olefins as coupling partners. Chiral imidazolidinones or prolinols, in combination with a thiophenol, iridium photoredox catalyst and visible light, have been successfully used in a triple catalytic process that is temporally sequenced to deliver a new hydrogen and electron-borrowing mechanism. This multicatalytic process enables both intra- and intermolecular aldehyde α-methylene coupling with olefins to construct both cyclic and acyclic products, respectively. With respect to atom and step-economy ideals, this stereoselective process allows the production of high-value molecules from feedstock chemicals in one step while consuming only photons.

尽管已经确定了酮的α-烷基化，但是使用醛底物的类似反应已被证明是难以捉摸的。尽管这两类化合物在结构上相似，但是醛官能团的灵敏度和独特的反应性通常需要活化的底物或特殊的添加剂。在这里，我们显示了光催化氧化，烯胺和氢原子转移（HAT）三种催化过程的协同合并，使对映选择性α-醛烷基化反应得以实现，该反应采用简单的烯烃作为偶联伙伴。手性咪唑烷酮或脯氨醇，与苯硫酚，铱光氧化还原催化剂和可见光结合使用，已成功地用于三重催化过程，该过程在时间上进行了排序，以提供新的氢和电子借入机理。这种多催化方法使烯内和分子内醛α-亚甲基与烯烃偶合，从而分别构建环状和非环状产物。关于原子和阶跃经济理想，这种立体选择性过程允许在仅消耗光子的情况下一步就由原料化学物质生产高价值分子。