Electro-catalytic Trifluoromethylation Of Alkenes

The fluorine-containing group has a significant effect on properties such as lipophilicity,permeability,and metabolic stability of compounds.Therefore,the efficient introduction of fluorine-containing groups into pharmaceutical and agrochemical compounds,as well as functional organic materials,has become an important research field of chemistry.Undoubtedly,new methodologies for the efficient and highly selective incorporation of fluorinated substituents into diverse molecular structures continue to be in strong demand.During the past few years,electrosynthesis has been considered to be a practical and environmentally friendly synthetic tool.The application of electrochemical anodic oxidation in synthetic organic chemistry has drawn increasing attention.Electrochemistry utilizes direct interaction of electrons from the anode and cathode with the nucleus,avoids using strong oxidants,and minimizes byproduct formation.This paper mainly consist of two parts:the first part is synthesis of?-trifluoromethyl/difluoromethyl-substituted ketones starting from styrenes based on electro-catalytic methods;another part is hydroxytrifluoromethylation of styrenes also using the Langlois reagent as the trifluoromethyl source and using electrosynthesis methods on the foundation of the first part.Of which the optimum reaction conditions of generating?-trifluoromethyl-substituted ketones is as follows:1 eq.styrenes,2 eq.sodium triflinate,a mixture of CH₃CN and H₂O(v/v 2:1)as the optimal solvent,adding 0.2 M electrolyte lithium perchlorate and CF₃COOH,carbon anode as platinum cathode,constant current 20 m A,room temperature for 6 h,giving the?-trifluoromethyl-substituted ketones in good yields(70%?88%).The optimum reaction conditions of?-trifluoromethyl alcohols is as follows:1 eq.styrenes,2 eq.sodium triflinate,DME as the optimal solvent,adding 0.2 M electrolyte n-Bu₄NCl O₄ and Ac OH,carbon anode as platinum cathode,constant current 15 m A,room temperature for 4 h,giving the?-trifluoromethyl alcohols in good yields.Under undivided electrolysis conditions,a comprehensive scope of the developed process and the tolerance of a variety of functional groups were successfully demonstrated.