Method for synthesizing dibenzocycloheptane derivatives by series cyclization of free radicals under electrooxidation conditions

A method for synthesizing dibenzocycloheptenone having a formula (III) by series cyclization of free radicals under electrooxidation conditions, comprising:

• electrifying and reacting the raw materials in an electrolytic cell followed by deprotonation to obtain dibenzocycloheptenone as shown in the following path, wherein the compound having a formula (I) and sodium benzenesulfinate are used as raw materials;
• wherein:
• in the formula (I), Ar is an alkyl or a halogen-substituted benzene ring;
• R1 is selected from the group consisting of H, alkyl, halogen atom, ester, and alkoxy;
• and
• R2 is aryl;
• the sodium benzenesulfinate have a structure as shown of formula (II):
• in the formula (II), R is H, alkyl, halogen atom, nitro, cyano or alkoxy;
• electrolyte solution in the electrolytic cell has a concentration of 0.1 mole per liter (mol/L);
• the electrolyte solution includes tetraethylammonium perchlorate as electrolyte, the electrolyte solution also includes a compound solvent of acetonitrile and water as solvents, and the acetonitrile is in a volume ratio of 3:1 to the water;
• and
• the electrolytic cell includes a carbon electrode graphite felt as an anode, and platinum or nickel as a cathode;
• and the electrifying and reacting is carried out under a reaction temperature of 50 degree Celsius (° C.), a constant current of 4 milliampere (mA), and a reaction duration of 6 hours (h).