Bromination of 5‐Methoxyindane: Synthesis of New Benzoindenone Derivatives and Ready Access to 7H‐Benzo[c]fluoren‐7‐one Skeleton

Unexpected metal-free transformation of gem-Dibromomethylenes to ketones under acetylation conditions

Novel conditions for the transformation of gem-dibromomethylenes to ketones are described. gem-Dibromo compounds were treated with acetic anhydride and triethylamine in dichloromethane/water at room temperature under an air atmosphere to give the corresponding ketones in moderate yields. A radical mechanism is proposed based on experimental results.

Synthesis of Bromoaminoindane and Bromoaminoindanone Derivatives

The bromination reactions of 5-aminoindane, 5-acetamidoindane, and 5-acetamidoindan-1-one were investigated using NBS, molecular bromine and photobromination, and the optimum reaction conditions were presented. The reaction of 5-aminoindane with glacial acetic acid at reflux temperature resulted in the formation of 5-acetamidoindane in high yield. 5-Acetamidoindan-1-one was generated by the reaction of 5-acetamidoindane with CrO3 in acetic acid. Selective bromination at C-6 position of 5-acetamidoindane was achieved by treatment of title compound with bromine in acetic acid and thus afforded 5-acetamido-6-bromoindane. Further bromination reactions of bromoindanones were achieved in various reaction conditions.