Cyclopropyl-1,1-dicarboxylic acid(10 g, 77 mmol) in THF (100 mL) was cooled in an ice-water bath, and Triethylamine (8.0 g, 79 mmol) was added dropwise. The temperature of the ice bath during the dropping process is controlled below 10 degrees. The resulting solution was stirred for 30 minutes, and then thionyl chloride (SOCl2, 9.0 g, 76 mmol). Then, dropwise, 4-fluoroaniline (9.0 mL) of THF (30 mL) was added. The ice bath temperature during the whole dripping process is controlled below 10 degrees. The stirring continued for 4 hours, and the reaction was warmed to room temperature. The reaction was diluted with 200 mL of EtOAc And then washed with aqueous NaOH (1.0 M, 50 mL), water (40 mL), and saturated brine (40 mL). The resulting organic solution was dried over Na2SO4, suction filtered, and evaporated to ~ 30 mL. To the resulting viscous liquid was added heptane (200 mL), and a lot of flaky solid precipitated. Filtration and drying gave 1-((4-Fluorophenyl)carbamoyl) cyclopropane carboxylic acid (15.8 g, 93 percent).
