Electrocatalytic Olefin Difunctionalization

Electrocatalytic synthesis is one of the most direct methods of organic synthesis,which can promote organic chemical reactions by gaining and losing electrons at the electrode.The biggest advantage of electrochemical synthesis is that it uses clean electrons as the oxidant or reducing agent of the reaction system.Requirements for the development of green chemistry.Considering that the bifunctionalization of olefins can increase the complexity of the molecules in a concise manner,this paper uses inexpensive and easily available styrene as a substrate,and uses the in-situ generated chlorine radicals to add olefins and the subsequent reaction process.,Innovatively developed an electrosynthesis way for the preparation of a pharmaceutical intermediate chloroacetophenone with important synthetic value through electrochemical means.Compared with the traditional generation of chlorine radicals by the decomposition of strong electrophilic chlorine reagents（such as Cl₂ and NCS,etc.）,this article mainly produces chlorine radicals through the transition metal catalysis:using inexpensive Mg Cl₂ as the chlorine source,by using controlled chlorine The manganese/cobalt catalyst produces chlorine radicals and uses oxygen as an oxygen source to form a carbonyl group at the benzyl position.The reaction conditions are mild and easy to operate.Compared with the complicated screening operation of traditional conditions,this article can easily achieve precise electrocatalytic synthesis using cyclic voltammetry:by using an electrochemical workstation instead of screening the reaction conditions through repeated chemical experiments based on yield,it can alternatively based on cyclic voltammetry of electric potential to optimize the functionalization of electrochemical oxychlorination of olefins.1)The oxidation potential of each component is obtained by cyclic voltammetry,and the reaction can be initiated by anodizing Mn（II）Cl₂ to Mn（III）Cl₂ and releasing chlorine radicals.The optimal reaction conditions are:lithium perchlorate（Li Cl O₄）as electrolyte,acetone-dichloromethane as solvent,RVC（+）-RVC（-）as electrode,Manganese chloride（10 mmol%eq.）is the catalyst,and magnesium chloride hexahydrate is the chlorine source.The reaction is carried out at 40°C and O₂atmosphere for 12 h with the highest yield of 93%.2)The relatively low oxidation potential of reversible CV and active complexes can be used as the basic criterion for CV optimization.At the same time,cyclic voltammetry,an unconventional screening method,was used to find the conditions for high yields of styrene to chloroacetophenone in a reasonable,time-saving and energy-saving manner.The optimal reaction conditions are:lithium perchlorate as electrolyte,Acetone-Dichloromethane（59:1）as solvent,graphite C（+）-graphite C（-）as electrode,under 40℃and O₂ at 5 h,the highest yield was 88%.Overall,we have designed a new strategy of electrocatalytic free radical olefins with chlorine and carbonyl difunctionalization using inexpensive and readily available chloride salts as the chlorine source and manganese chloride or cobalt chloride.These two types of strategies have many advantages such as high efficiency,low energy consumption,green environmental protection,high atom utilization rate,simple steps,simple operation,wide substrate range,etc.,which provide new synthetic ideas for the preparation of chloroacetophenone It has certain significance in the fields of organic chemistry,material chemistry and medicinal chemistry.