A 50 mL round-bottom flask was charged with 1,1,1,3,3,3-hexafluoropropan-2-ol (120 mg, 0.710 mmol, 1.00 equiv), triphosgene (70.0 mg, 0.240 mmol, 0.33 equiv), dichloromethane (10 mL). N,N-Diisopropylethylamine (338 mg, 2.62 mmol, 3.65 equiv) was added dropwise. The mixture was stirred at room temperature for 2 hours. 4-[2-Fluoro-6-(piperazin-1-ylmethyl)phenyl]morpholine (200 mg, 0.720 mmol, 1.00 equiv) was added. The resulting solution was stirred for 2 hours at room temperature and diluted with H2O (10 mL). The resulting solution was extracted with dichloromethane (3×20 mL) and the organic layers were combined, washed with H2O (3×10 mL), dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was chromatographed on a silica gel column with ethyl acetate/petroleum ether (1/4). The crude product (217 mg) was purified by preparative HPLC using the following gradient conditions: 20% CH3CN/80% Phase A increasing to 80% CH3CN over 10 min, then to 100% CH3CN over 0.1 min, holding at 100% CH3CN for 1.9 min, then reducing to 20% CH3CN over 0.1 min, and holding at 20% for 1.9 min, on a Waters 2767-5 Chromatograph. Column: Xbridge Prep C18, 19*150 mm 5 um; Mobile phase: Phase A: aqueous NH4HCO3 (0.05%); Phase B: CH3CN; Detector, UV220 & 254 nm. Purification resulted in 125.4 mg (36% yield) of 1,1,1,3,3,3-hexafluoropropan-2-yl 4-[[3-fluoro-2-(morpholin-4-yl)phenyl]methyl]piperazine-1-carboxylate as light yellow oil. 1H NMR-300 MHz (CDCl3) δ 7.07-7.18 (m, 2H), 6.94-7.01 (m, 1H), 5.71-5.83 (m, 1H), 3.88 (br, 4H), 3.80 (br, 2H), 3.52-3.54 (m, 4H), 3.10 (br, 4H), 2.49-2.52 (m, 4H). LCMS (ESI, m/z): 474 [M+H]+.
