Photo catalysis has comprehensively become a powerful tool in organic synthesis, and organic molecules are thriving as catalyst. The thioxanthone-TfOH complex (9-HTXTF) as photoredox catalyst with high oxidative capacity can be applied in single electron reduction of alkene affording alkene radical anion as a key intermediate. To transform this intermediate from radical anion to radical cation, a well-designed strategy is proposed with N-arylacrylamides as substrate. Based on its single electron transfer (SET) with 9-HTXTF*, N-radical cation is generated and then transformed to alkene radical cation by intramolecular conjugated system. By using this photoredox catalysis strategy, we developed a 9-HTXTF-catalyzed photochemical cyclization of alkenes, which further expands the applications of this catalyst. The entire cyclization is metal-free and without sacrificing agents, which conforms to atom economy and environmental friendliness.

中文翻译：

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使用光氧化还原催化策略生成烯烃自由基阳离子，用于噻杂蒽酮-TfOH 复合物催化的分子内环化


光催化已经全面成为有机合成的有力工具，有机分子作为催化剂蓬勃发展。噻杂蒽酮-TfOH 络合物 （9-HTXTF） 作为具有高氧化容量的光氧化还原催化剂，可用于烯烃的单电子还原，提供烯烃自由基阴离子作为关键中间体。为了将这种中间体从自由基阴离子转化为自由基阳离子，提出了一种以 N-芳基酰胺为底物的良好设计策略。基于其与 9-HTXTF* 的单电子转移 （SET），生成 N-自由基阳离子，然后通过分子内共轭系统转化为烯烃自由基阳离子。通过使用这种光氧化还原催化策略，我们开发了一种 9-HTXTF 催化的烯烃光化学环化反应，进一步扩展了该催化剂的应用。整个环化过程不含金属，无牺牲剂，符合原子经济性和环保性。