Visible-light-driven photoredox catalysis is known to be a powerful tool for organic synthesis. Its occurrence critically depends on the twice exothermic single-electron transfer processes of photosensitizers, which are governed by the redox properties of the species involved. Hence, the inherently narrow range of redox potentials of photosensitizers inevitably constrains their further availability. Sensitization-initiated electron transfer has recently been found to effectively overcome this substantial challenge. However, feasible and practical strategies for designing such complicated catalytic systems are rather scarce. Herein we report an elaborate dual-catalyst platform, with dicyanopyrazine as a visible light photosensitizer and a pyrenyl-incorporated chiral phosphoric acid as a co-sensitizer, and we demonstrate the applicability of this sensitization-initiated electron transfer strategy in an asymmetric formal de Mayo-type reaction. The catalysis platform enables otherwise thermodynamically unfavourable electron transfer processes to close the redox cycle and allows for precise access to valuable enantioenriched 1,5-diketones with a wide substrate range.

可见光驱动的光氧化还原催化被认为是有机合成的强大工具。它的发生关键取决于光敏剂的两次放热单电子转移过程，该过程由所涉及物种的氧化还原性质控制。因此，光敏剂固有的狭窄氧化还原电位范围不可避免地限制了它们的进一步可用性。最近发现敏化引发的电子转移可以有效克服这一重大挑战。然而，设计这种复杂催化系统的可行且实用的策略却相当稀缺。在此，我们报告了一种精心设计的双催化剂平台，其中二氰基吡嗪作为可见光光敏剂，并掺有芘基的手性磷酸作为共敏化剂，并且我们证明了这种敏化引发的电子转移策略在不对称形式 de Mayo 中的适用性。型反应。该催化平台能够实现热力学上不利的电子转移过程来关闭氧化还原循环，并允许在多种底物范围内精确获得有价值的对映体富集的 1,5-二酮。