Synergistic Br?nsted Base/Photoredox-Catalyzed Three-Component Coupling with Malonates to Synthesize -Hydroxy Esters and -Keto Esters

Multicomponent alkene 1,2-dicarbofunctionalizations (DCFs) have emerged as a powerful strategy to rapidly incorporate both two carbon subunits across one C-C double bond in one step for enhancing molecular complexity and diversity. To the best of our knowledge, there is only one report on photoredox-catalyzed three-component DCFs with malonates through the radical-radical cross-coupling, while photoredox-catalyzed radical-polar crossover (RPC)-type DCFs with malonates were still rare. Herein, we describe a redox-neutral RPC-type 1,2-dialkylation of styrenes with malonates and aldehydes through the synergistic Bronsted base/photoredox catalysis system. This transition-metal-free strategy provides an efficient and clean approach to a broad variety of delta-hydroxy esters and also features exceptionally mild conditions, wide compatibility of substrate scope and functional groups, and high atomic economy. Moreover, three-component 1,2-alkylacylation from the same starting materials was achieved in one-pot manner through such RPC-type coupling and subsequent two-electron oxidation process, providing a set of delta-keto esters of interest in pharmaceutical research.