Electrochemically Promoted Oxidative Halogenation Of Alkenyl Amides To Construct Halogenated Benzoxazines And Oxazoline Derivatives

Organic electrochemistry is an interdisciplinary subject of organic chemistry and electrochemistry.Electrochemical organic synthesis uses the gains and losses of electrons instead of oxidizing/reducing agents to achieve the redox of compounds.Electrochemical organic synthesis can realize reaction processes such as reduction,oxidation,cleavage,coupling,elimination of functional groups,and formation of carbon-carbon bonds.With the vigorous development of science and technology,environmental issues cannot be ignored.How to make the reaction process more in line with the concept of "green chemistry" is a question that researchers have explored in recent years.Electrochemical synthesis is a sustainable method and has obvious advantages compared with traditional organic chemistry.There is no need for toxic catalysts and oxidants in the reaction process,"electrons" are the cleanest energy;the reaction conditions are mild and simple,most of which do not require heating and pressure,and the reaction time is relatively shorter;the reaction process can also be controlled simultaneously with good selectivity.The reaction rate can be adjusted by adjusting the voltage and current,and even the switch of the reaction can be controlled.Electrochemical synthesis provides researchers with new methods and strategies.In this thesis,an efficient and eco-friendly electrochemical method involving halogenation of N-allylamides using inorganic halide salt as the halogen source to synthesize various halogenated benzoxazine and oxazoline derivatives under mild reaction conditions has been developed(X = Br,Cl).Stoichiometric oxidants,metal catalysts,and even external electrolytes were avoided in this method.We have investigated the solvents,supporting electrolytes,current density and electrode materials on the yield of the reaction.And this reaction has good substrate tolerance,and most of which received the target products by a moderate to excellent yields.We also have studied the possible reaction mechanism with the assistance of control experiments and cyclic voltammetric(CV)experiments.In summary,we have successfully developed the use of electrochemical methods to realize the electrophilic cyclization of N-allylamides to construct halogenated benzoxazine and oxazoline derivatives.Compared with traditional organic chemistry,electrochemical synthesis has the advantages as easy access to non-toxic reagents,safe and mild conditions,and high atom economy,which provides new ideas for green chemical synthesis.