General procedure for the synthesis of 3-methylenecyclobutanecarboxylic acid from 3-methylenecyclobutanecarboxylic acid: 3-methylenecyclobutanecarboxylic acid (1 g) was mixed with Pd/C catalyst (0.19 g) in methanol (20 mL) and the reaction was stirred overnight at room temperature in a hydrogen atmosphere (H2 balloon). Upon completion of the reaction, the mixture was filtered to remove the catalyst and the filtrate was concentrated under vacuum to give the target product 3-methylcyclobutyric acid (760 mg). Mass spectrometry analysis (ESI): calculated mass of C6H10O2 was 114; no corresponding mass was detected.
