1: 100 percent / p-TsOH*H2O / methanol / 24 h / 60 °C 2: pyridine / 3 h / 20 °C 3: 165 mg / pyridine; 4-(dimethylamino)pyridine / 27 h / 20 °C 4: 99 percent / HF / acetonitrile / 7 h / 20 °C 5: H2CrO4 / acetone / 6 h / 0 - 20 °C 6: aq. NaOH / 10 h / 20 °C 7: 96 percent / bis(2-oxo-3-oxazolidinyl)phosphinic chloride; Et3N / CH2Cl2 / 3 h / 20 °C View Scheme

1: 100 percent / p-TsOH*H2O / methanol / 24 h / 60 °C 2: pyridine / 3 h / 20 °C 3: 165 mg / pyridine; 4-(dimethylamino)pyridine / 27 h / 20 °C 4: 99 percent / HF / acetonitrile / 7 h / 20 °C 5: H2CrO4 / acetone / 6 h / 0 - 20 °C 6: aq. NaOH / 10 h / 20 °C View Scheme