Sodium t-butoxide (2–4 equiv) was added to a solution of the Boc protected amine (1 equiv) in 2-methyltetrahydrofuran or tetrahydrofuran (10 vol). Volumes is defined as mL of solvent per gram of starting material. Water (1 equiv) was added and the reaction was heated at reflux for 2–12 h. The reaction was cooled to room temperature and quenched with 10% citric acid solution (10 vol). The resulting solution was stirred at room temperature for 30–60 min and then the pH was adjusted to 10–12 with 6 N NaOH solution. The layers were separated. The aqueous layer was further extracted with ethyl acetate (10 vol). The combined organic layers were dried and concentrated to afford the desired amine in 90% to quantitative yield. The crude amine was generally of excellent purity but the crude reaction can be purified by column chromatography or recrystallization if necessary.
Tetrahedron Letters 2004, 45, 905–906