1.1: EtOCOCl; Et3N / tetrahydrofuran / 1.17 h / -15 °C 1.2: 81 percent / NaBH4 / tetrahydrofuran; H2O / 2 h / 20 °C 2.1: 100 percent / pyridine / CH2Cl2 / 2 h / 20 °C View Scheme

hydrogenchloride in ethyl acetate 2 h; Ambient temperature;