4-[2-(Toluene-4-sulfonyloxymethyl)phenyl]piperidine-1-carboxylic acid t-butyl ester (2.1 g, 4.7 mmol, 1.0 eq.) was dissolved in MeCN (46 mL, 890 mmol) and added to K2CO3 (1.9 g, 14 mmol, 3.0 eq.) and 2,4,6-trifluorophenol (1.0 g, 7.0 mmol, 1.5 eq.). The mixture was shaken at 50° C. overnight, then cooled to room temperature. The supernatant was separated from the K2CO3 and other solids. TFA (7 mL, 90 mmol, 20.0 eq.) was added to the supernatant and the mixture was shaken overnight at room temperature. The solution was then concentrated to yield a crude residue. The residue was dissolved in 5.0 mL 1:1 AcOH/H2O, then in an additional 2.0 mL AcOH, filtered and purified by preparative HPLC to yield the title compound as a TFA salt (1.3 g, 97.5% purity). MS m/z: [M+H]+ calcd for C18H18F3NO, 322.13. found 322.2.
