To a stirred solution of tert-butyl (piperidin-4-ylmethyl)carbamate (38.8 g, 181 mmol) in N,N-dimethylformamide (100 mL) was added benzyl 3-chloropivalate {14.2 g, 124 mmol, prepared from 3-chloropivaloyl chloride (25.6 g, 165 mmol) and benzyl alcohol (19.6 g, 181 mmol), ethyldiisopropylamine (64.0 g, 495 mmol) and sodium iodide (27.1 g, 181 mmol) at ambient temperature. The resulting mixture was stirred at 120° C. for 14 h. The volatile components were removed by evaporation and the resulting residue was chromatographed on a column of silica gel eluting with hexane/ethyl acetate (1:1) to give 640 mg (1%) of the title compound as a pale yellow oil.
