1.1: ethyl chloroformate; Et3N / tetrahydrofuran / 0.5 h / 0 °C 1.2: 70 percent / tetrahydrofuran / 1 h / 20 °C 2.1: 55 percent / LiBH4 / dioxane / 0.5 h / 20 °C 3.1: 60 percent / aq. HCl / 0.5 h / Heating 4.1: 64 percent / morpholine / toluene / 3 h / Heating 5.1: [(CH3)3Si]2NLi / tetrahydrofuran / 0.5 h / -78 °C 5.2: 53 percent / (2R,8aS)-(+)-(camphorylsulfonyl)oxaziridine / tetrahydrofuran / 3 h / -78 °C View Scheme