Electrocatalytic Formation And Cleavage Of C-O Bond Mediated By Halogen Ions

Organic electrochemical synthesis is a green method in which catalysts or substractes gain or loss electrons from electrodes to finish redox processes. It is a green synthetic means without adding additional oxidizing or reducing agent. Halogen ion is a cheap and environmental friendly catalyst widely used in a variety of reactions, and they can be oxidized to 0, +1, +3, +5, +7 valences. Therefore, in order to catalytic the reaction effectively we can obtain specific oxidation state ions by controlling the potential and other factors.In order to implement the concept of green chemistry, we will continue to explore the new method in which halogen ion as a catalyst, we believe that in the future the halogen ion used as a catalyst applications in organic electrochemical synthesis will gain more and more people's attention. In this paper for the formation and cleavage of C-O bond, our work was carried following the two parts:1) Electrochemical synthesis of isoxazoles and dihydroisoxazales mediated by halogen ions.A series of isoxazoles and dihydroisoxazales was efficiently synthesized by electrochemical oxidation in undivided cell, using inorganic halogen as mediator. In our work, several parameters that may influence the reaction, including the type of mediator and solvent have been initially investigated. Under the opitimized reaction conditions, an electrochemical approach for the synthesis of isoxazoles and dihydroisoxazales is developed. All products are characterized by 1H NMR. The possible mechanism of the reaction is finally proposed.2) The cleavage of ?-O-4 bonds in lignin model molecules under electrochemical conditions.We further studied the cleavage of ?-O-4 bonds in lignin model molecules under electrochemical conditions. In this process, several parameters that may influence the reaction, including type of mediator, amount of mediator, solvent, current density, the electrode material, substrate type and so on, have been initially investigated. Under the opitimized reaction conditions, an electrochemical approach for the cleavage of ?-O-4 bonds in lignin model molecules is developed. All products are characterized by 1H NMR. The method has advantages of mild reaction conditions, and excess oxidant is not required.