935273-86-2

107496-54-8

General procedure for the synthesis of 3,3-difluorocyclobutanecarboxylic acid from benzyl ester of 3,3-difluorocyclobutanecarboxylate: benzyl ester of 3,3-difluorocyclobutanecarboxylic acid (0.84 g, 3.72 mmol) was dissolved in ethanol (40 mL), and about 0.02 g of palladium/activated carbon catalyst was added. The reaction mixture was stirred at room temperature for 12 hours in a hydrogen atmosphere. Upon completion of the reaction, the catalyst was removed by filtration through a diatomaceous earth pad. The filtrate was concentrated and dried under vacuum to afford the target product 3,3-difluorocyclobutanecarboxylic acid (0.46 g, 90% yield). The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3): δ 3.16-2.55 (m, 5H).