Electrochemical Synthesis Of Sulfoxide Compounds From Sulfides

Electrochemical synthesis is a green,efficient and sustainable organic synthesis scheme.The scheme uses traceless electrons as oxidant,avoiding the use of traditional highly toxic and corrosive oxidants.It has the characteristics of green and environmentfriendly synthesis scheme,as well as the advantages of mild reaction conditions and simple operation.Without adding any other additives,the selectivity of the reaction system can be effectively controlled by adjusting the current and voltage of the reaction system to match the reaction substrate.At present,electrochemical oxidation reactions have been extensively studied in the field of organic synthesis.The most common of which include oxidation processes that directly transfer electrons on the surface of the electrode and indirect oxidation processes that achieve electron transfer between the electrode,medium,and substrate under the action of redox media.Sulfoxide compounds are commonly found in functional organic compounds,and are also widely used in natural drugs or materials.The research on the synthesis methods of sulfoxide compounds has always been a hot topic in the field of organic synthesis.The addition of strong oxidants in traditional oxidation reactions,the catalytic oxidation of metal catalysts,and the use of light energy under the rapid development of photochemistry,are all important research directions in the synthesis of sulfoxide compounds.However,these methods each have certain shortcomings,including: the excessive oxidation of sulfoxide caused by the addition of excessive oxidant,the waste of resources or environmental pollution caused by the massive use of metal catalysts,and the difficulty of large-scale mass production of the reaction system due to the insufficient catalytic efficiency of photosensitizers in the development of photochemistry.It is necessary to develop a simple,green and sustainable practical scheme for the selective synthesis of sulfoxides.In this paper,a synthesis scheme for preparing sulfoxide compounds by oxidizing sulfides under electrochemical conditions has been developed.After optimization of the conditions,we determined to mix acetone and water as the optimal solvent for the reaction,Na Cl was the electrolyte and the oxidation-reduction medium to promote the reaction,and double graphite felt electrode was used for electrolysis under constant current of 5 m A at room temperature for 2 hours.Sulfoxide compounds were obtained with high selectivity,avoiding excessive oxidation.This scheme could be effectively applied to monoaryl or biaryl substrates,and realized the synthesis of sulfoxide drug molecules.In addition,the excellent electrode usage cycle and the 10 gram-scale reaction provide the feasibility basis for industrial mass production.Finally,the possible mechanism of the reaction was proposed through a series of control experiments.