Radical Oxidative Coupling Reaction Of Alkenes With 1,3-Dithiane

1,3-dithiane (1,3-dithiane) is an important organic functional group reagent, which play an important role in the field of formation of C-C bonds. In recent decades,1,3-dithiane is widely used in organic synthesis, such as the synthesis of important pharmaceutical intermediates, natural products, organic materials chemistry and theoretical chemistry.1,3-dithiane can be seen as a carbonyl protecting group, it can serve as a strong nucleophile by "Umpolung", and react with many electrophilic reagents such as halides, aldehydes, ketones, epoxy compounds and olefin to construct carbon-carbon bonds. But the reaction conditions of traditional method is very harsh, this make some trouble in the application of it. Thus, it is necessary to develop a more general and milder procedure to solve this proble.The coupling reaction is an important method to construct chemical bonds in organic synthetic chemistry. Oxidative coupling reaction which is a very important part of it, and has been developed and applicated for a long time. Also There is a path of free radical oxidative coupling reaction, which we named it radical oxidative coupling, this type of reaction give the active radicals under oxidizing conditions, then occurred the coupling procedure. Our team has successfully applied oxidative coupling to 1,3-dithiane chemistry during its study, completed the coupling reaction of 1,3-dithiane with alkenes, the reaction has mild conditions, and easy to operate, even it can be complete by "one-pot".By trial and error and the optimization of conditions, firstly we achieved radical oxidative coupling of 1,3-dithiane with styrene compounds. We used FeCl3 as a catalyst, N-chlorosuccinimide as additive,1,2-dichloroethane as solvent, finally obtained the β-chloro-1,3-dithiane product; then We have also achieved the oxidative coupling of 1,3-dithiane with substituted olefin, we used boron trifluoride etherate as catalyst, even without any catalyst, oxygen in the air as the oxidant, N-chlorosuccinimide as additives,1,2-dichloroethane as solvent, by this reaction we obtained dithianyl-substituted alkene derivatives. In addition, the possible reaction mechanisms of these two reactions have been proposed and validated.