1: nBuLi / tetrahydrofuran / 1.) -70 deg C, 5 min, 2.) RT, 1 h 2: 1.) NaH / 1.) DMF, 0 deg C, 2.) DMF, 60 deg C, overnight 3: p-TsOH / methanol / 4 h / Ambient temperature 4: 1.) (COCl)2, DMSO, 2.) Et3N / 1.) CH2Cl2, -78 deg C, 30 min, 2.) CH2Cl2, from -78 deg C to RT 5: NH2OSO3H / H2O / 2.17 h / 50 °C View Scheme