Method 1: Dibenzo[a,d]cycloheptan-5-one was used as the starting material, and the target product was prepared by bromine bromination reflux reaction in CCl4 for 18h, followed by addition of triethylamine and then continued reflux for another 16h, and then after post-treatment. This method uses more toxic raw materials and the preparation reaction period is also longer.
Method 2: Using trans-dibromo-substitute as the substrate, the target product was prepared by reacting under light radiation via a Schlenk tube device under the action of argon protection and -selenothiophene and tetramethylethylenediamine. The preparation of the target product of this method is in milligram scale and requires column chromatography for purification, which is difficult for mass production.
Method 3: The target product 5-dibenzocycloheptenone was prepared by intramolecular decarboxylation coupling of 3-(2-benzoylphenyl)acrylic acid as starting material under the effect of silver catalyst and oxidizing agent.
