苏州大学鲍晓光团队研究了有机光氧化还原催化的胺类与亚砜酰脲环化以获得吡咯的自由基链机制。2025年6月10日出版的《中国化学》杂志发表了这项成果。

研究组在无过渡金属和温和的条件下，开发了有机光氧化还原催化烯胺与砜鎓叶立德环化以构建吡咯衍生物的方法。广泛的易于获得的底物适用于该方案，为制备吡咯衍生物提供了一种方便有效的方法，且产率令人满意。从机理上讲，通过协同实验和计算研究，为该反应提出了光氧化还原介导的自由基链机理途径。 

在光氧化还原催化环中，可以通过两步单电子转移产生两个关键基团，分别是烯胺和砜鎓叶立德衍生的α-亚氨基和α-羰基C-基团。随后，形成的α-羰基C基团可能会攻击烯胺的烯基部分。接下来，形成的自由基加合物可以与砜鎓叶立德进行H原子转移，以再生关键的α-羰基C自由基，从而完成链的传播过程。所提供的加合物中间体可以进行分子内环化，然后脱水以提供所需的吡咯衍生物。

附：英文原文

Title: Organophotoredox-Catalyzed Annulation of Enamines with Sulfoxonium Ylides to Access Pyrroles via Radical Chain Mechanistic Scenarios

Author: Yujing Wang, Mengyu Xu, Rui Fu, Jiaxin Lin, Mengting Cao, Xiaoguang Bao

Issue&Volume: 2025-06-10

Abstract: Herein, organophotoredox-catalyzed annulation of enamines with sulfoxonium ylides to construct pyrrole derivatives is developed under transition-metal-free and mild condition. A broad range of readily accessible substrates are suitable for this protocol, providing a convenient and efficient approach to preparing pyrrole derivatives with satisfying yields. Mechanistically, a photoredox-mediated radical chain mechanistic pathway is proposed for this reaction by a synergistic experimental and computational study. Two key radicals, α-imino and α-carbonyl C-radicals derived from enamines and sulfoxonium ylides, respectively, could be generated via two steps of single-electron transfer in a photoredox catalytic loop. Subsequently, the formed α-carbonyl C-radical may attack the alkenyl moiety of enamines. Next, the formed radical adduct could undergo H-atom transfer with sulfoxonium ylides to regenerate the key α-carbonyl C-radical and thus fulfill the chain propagation process. The afforded adduct intermediate could undergo an intramolecular cyclization followed by dehydration to furnish the desired pyrrole derivatives.

DOI: 10.1002/cjoc.70109

Source: https://onlinelibrary.wiley.com/doi/10.1002/cjoc.70109