河南大学江智勇团队报道了敏化引发电子转移的不对称光氧化还原催化de Mayo反应。相关研究成果发表在2024年4月2日出版的《自然—化学》。

可见光驱动的光氧化还原催化是有机合成的有力工具。它的发生在很大程度上取决于光敏剂的两次放热单电子转移过程，这是由所涉及物种的氧化还原特性决定的。因此，光敏剂氧化还原电位的固有窄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地克服这一重大挑战。然而，设计这种复杂催化体系的可行和实用的策略相当匮乏。

该文中，研究人员报道了一种精细的双催化剂平台，以双氰基并吡嗪作为可见光光敏剂，以掺入芘的手性磷酸作为共敏化剂，并证明了这种敏化引发的电子转移策略，在不对称形式的de Mayo型反应中的适用性。催化平台使热力学上不利的电子转移过程能够关闭氧化还原循环，并能够精确获得具有宽底物范围的有价值的富含对映体的1，5-二酮。

附：英文原文

Title: Asymmetric photoredox catalytic formal de Mayo reaction enabled by sensitization-initiated electron transfer

Author: Sun, Xin, Liu, Yilin, Yin, Yanli, Ban, Xu, Zhao, Xiaowei, Jiang, Zhiyong

Issue&Volume: 2024-04-02

Abstract: 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.

DOI: 10.1038/s41557-024-01502-3

Source: https://www.nature.com/articles/s41557-024-01502-3