1: 64 percent / hydroxylamine hidrochloride, KOH / tetrahydrofuran; ethanol / Ambient temperature 2: n-BuLi / hexane; tetrahydrofuran / 1 h / Ambient temperature 3: concentrated H2SO4 / tetrahydrofuran; hexane / 1 h / Heating 4: p-toluenesulfonic acid monohydrate / Ambient temperature 5: n-BuLi / hexane; tetrahydrofuran / 1 h / -70 °C 6: concentrated HCl / tetrahydrofuran / Ambient temperature View Scheme