Research On The Reduction Of Sulfoxides To Thioethers Under Solvent-free Conditions

Thioether compounds are widely used in fine chemical industry,extraction and separation of rare and precious metals.Therefore,the study of the methodology for the construction of thioether compounds is of great significance.During the past few decades,various methods have been well established to reduction of sulfoxide compounds to thioether compounds,The thioether synthesis methods currently mainly include:Direct oxygen atom transfer reaction,metal reduction,reduction by phosphonium halide,reduction by thiosulfoxide,catalytic reduction,and etc.However,there are still shortcomings such as the use of expensive catalysts,harsh reaction conditions,the use of dry volatile toxic reagents,and poor resistance to functional groups.The paper reported dimethyl thioformyl chloride and phenyl chloroformate to reduce sulfoxides to thioethers under solvent-free conditions.The reaction steps are as follows:(1)Dimethylamino thiocarbonyl chloride(3 eq)was started at a temperature of 100 ? and a variety of thioether compounds with moderate yields(up to 92%)were obtained after the reaction.;(2)Phenyl chloroformate(1.5 eq)was started at a temperature of 80 ? and a variety of thioethers compounds with moderate yields(up to 86%)were obtained after the reaction.The above two synthesis methods are one-step reduction reactions under solvent-free conditions,and have the advantages of simple operation,mild reaction conditions,strong functional group tolerance,short reaction time,high yield of target compounds,and simple post-treatment,etc.