Preparation Of Selenium Esters Catalyzed By In（OTf）₃

Selenium esters are widely used in medicine and pesticides,because their special structure enables certain compounds with good physiological and medicinal activities.Derivatives of selenium and selenoesters have been utilized in peptide connection,as acyl radicals and participating in the synthesis of natural products.In the reported methods of synthesizing selenium ester compounds,some nucleophiles containing selenium,such as diselenide,selenol,selenophenol were used.Promoted by Lewis acid The reported methods have some disadvantages.such as were wasted in catalyst,high reaction temperature,long reaction time and harsh reaction conditions.Therefore,it is necessary to develop a new reaction system to prepare selenium esters with high yield and mild reaction condition.In our research,a reaction system for preparation of selenium esters using（RSe）₂ as nucleophile with In（OTf）₃ as catalyst and In as reduction reagent was developed.The research content is mainly divided into two parts:The first part:First,use the acid chloride as starting material to react with different diselenide under the catalysis of Lewis acid to carry out esterification in a reducing system.The catalyst,reduction reagent solvent,and temperature are screened,and a high-yield synthetic route can be obtained in a low temperature environment.Under this reaction condition,a series of selenium ester compounds were synthesized by replacing the substrate.The second part:Due to the high yield of the first reaction route and the stable product properties,preparation selenium ester compounds using acid anhydrides with lower activity as raw materials was researched.The catalyst,solvent,and temperature were also screened to find out the most suitable reaction conditions.Through the study of the above two reaction routes,it is found that when selenium ester is synthesized from acid chloride,the reaction process is short and the yield is still high at-10°C.If the reaction is carried out at room temperature,the yield is generally above 85%.The synthesis of selenoesters using acid anhydride as the raw material,the reaction time is relative long,and the reaction is performed at 45°C,the yield is generally about 65%.