Synthesis
Methyl 2-(2,2-dichloro-3-oxocyclobutyl)acetate (0.6 g) was used as raw material, which was dissolved in acetic acid (5 mL) and zinc powder (0.929 g) was added. The reaction mixture was stirred at 100 °C for 15 hours. Upon completion of the reaction, the mixture was cooled to room temperature, diluted with ethyl acetate, and subsequently carefully neutralized with ice-cold saturated aqueous sodium bicarbonate solution at 0 °C. The aqueous phase was separated, extracted with ethyl acetate, the organic phases were combined and washed with saturated aqueous sodium bicarbonate solution. The organic phase was dried with anhydrous sodium sulfate, filtered and concentrated. The crude product was purified by column chromatography on 40 g silica gel using a 20-minute gradient of 0-90% ethyl acetate/hexane solution as eluent, resulting in methyl 2-(3-oxocyclobutyl)acetate (0.27 g). The product was characterized by 1H NMR (400 MHz, CDCl3) with chemical shifts of 3.63 (3H, s), 3.12-3.27 (2H, m), 2.68-2.81 (3H, m), 2.56-2.64 (2H, m).
References
[1] Patent: US2009/118287, 2009, A1. Location in patent: Page/Page column 74-75
[2] Patent: US2013/183269, 2013, A1. Location in patent: Paragraph 1332; 1333
[3] Patent: WO2015/5901, 2015, A1. Location in patent: Page/Page column 540; 541
