To a stirred solution of 4-hydroxy-4-methylpiperidine-1-carboxylic acid tert-butyl ester (0.500 g, 2.32 mmol) in toluene (10 mL) was added 2-hydroxybenzotrifluoride (0.414 g, 2.56 mmol), triphenylphosphine (0.682 g, 2.555 mmol) and diethyl azocarboxylate (0.5 mL, 2.56 mmol). The resulting mixture was stirred at reflux for 18 hours. Toluene was removed in vacuo and the obtained crude product was purified by column chromatography to yield the desired product, 4-methyl-4-(2-trifluoromethyl-phenoxy)piperidine-1-carboxylic acid tert-butyl ester, in 5% yield (0.025 g). 1H NMR (300 MHz, CDCl3) δ 7.57-7.54 (m, 1H), 7.41-7.36 (m, 1H), 7.09 (d, J=7.9 Hz, 1H), 7.02-6.97 (m, 1H), 3.81-3.76 (m, 2H), 3.28 (t, J=11.9 Hz, 2H), 2.15-2.11 (m, 2H), 1.67-1.58 (m, 2H), 1.44 (s, 9H), 1.39 (s, 3H).
