Step 1: trans-4-Aminocyclohexanol hydrochloride (5.0 g, 33 mmol) was dissolved in 1,4-dioxane (100 mL) and the resulting solution was cooled to 0 °C. Aqueous sodium hydroxide solution (40 mL, 1 N) was slowly added and the reaction mixture was stirred for 15 minutes. Subsequently, di-tert-butyl dicarbonate (7.9 g, 36 mmol) pre-dissolved in 1,4-dioxane (65 mL) was added. The reaction mixture was stirred at room temperature for 14 hours. Upon completion of the reaction, the reaction mixture was neutralized with 1 N hydrochloric acid and extracted with ethyl acetate. The organic phase was washed sequentially with 1 N hydrochloric acid, water and saturated saline, dried over anhydrous sodium sulfate, filtered and concentrated in vacuum to give the white solid product trans-4-BOC-aminocyclohexanol (7.0 g, 100% yield). Mass spectrometry analysis showed (M + H)+ = 216.15.
