1: 80 percent / p-toluenesulfonic acid monohydrate / 6 h / Ambient temperature 2: 64 percent / hydroxylamine hidrochloride, KOH / tetrahydrofuran; ethanol / Ambient temperature 3: n-BuLi / hexane; tetrahydrofuran / 1 h / Ambient temperature 4: concentrated H2SO4 / tetrahydrofuran; hexane / 1 h / Heating 5: p-toluenesulfonic acid monohydrate / Ambient temperature 6: n-BuLi / hexane; tetrahydrofuran / 1 h / -70 °C 7: concentrated HCl / tetrahydrofuran / Ambient temperature View Scheme