Visible Light Catalyzed Carbon-carbon Single/double Bond Amination

Visible light catalysis has attracted much attention because of its clean and mild conditions.Organic amines are widely used in the synthesis of drugs,materials and fine chemical,However,it is challenging to control the amination reactions of different chemical bonds with high regioselectivity.In this paper,the following two parts of work will be focused on the visible light catalyzed regioselective amination of Csp³-Csp³ and Csp²-Csp² bonds.First,the sulfonimide reaction of tertiary amine Csp³-Csp³ bond was successfully realized by using arylsulfonyl azide and tertiary amine as substrate and eosin Y as photosensitizer.Various linear,branched,cyclic aliphatic amines and aromatic amines,as well as electron donor/acceptor azides,can be converted to sulfonimide in moderate to excellent yields by 1,3-bipolarization.This method opens up a simple route for the rapid and efficient synthesis of diverse sulfonimides.The mechanism study shows that the reaction mechanism involves the formation of enamine intermediates,which then react with Sulfonyl azides via1,3-bipolarization reaction that takes place in the way of five membered ring transition state,and one molecule of CH₂N₂ or N₂ is removed,and realize the amination reaction of Csp³-Csp³ bond of tertiary amine.Although transition metal catalyzed amination of alkenes provides an effective synthesis channel for the synthesis of complex alkyl amines,it often suffer from the poor regioselectivity.In this paper,the amination of alkenes catalyzed by visible light was investigated using aryl alkenes or alkynes as substrates.By optimizing the reaction conditions such as catalyst and temperature,it was found that TPT/CF₃CO₂H system could form a variety of?-aryl substituted alkyl amines through the amination process of Markovian addition with high regioselectivity under visible green light.The substrate of this reaction has wide applicability with medium to excellent yields.The mechanism study shows that the reaction includes two possible reaction pathways.One is the traditional Bronsted acid promoted Markovnikov hydroamination reaction.Another pathway involves visible light assisted amination which the excited state photosensitizer TPT*is generated by light excitation.Meanwhile styrene is also activated to form triplet phenylene through energy transfer?En T?process,and then the triplet olefin is protonated to form benzyl carbonium ion species,attacked by aromatic amines,with the releases of protons to give Markovnikov hydroamination products.