1: 93 percent / p-chlorophenylphosphoro-dichloridate, pyridine / 24 h / Ambient temperature 2: 85 percent / Na / 0.25 h / Ambient temperature 3: 83 percent / NaOH / methanol; H2O / 12 h / Heating View Scheme

1: 93 percent / p-chlorophenylphosphoro-dichloridate, pyridine / 24 h / Ambient temperature 2: 92 percent / Na / 0.25 h / Ambient temperature 3: 95 percent / aq. NH3 / dioxane / 12 h / Ambient temperature 4: 81 percent / aq. NH3 / dioxane / 120 h / Ambient temperature View Scheme

1: 87 percent / Et3N, palladium acetate, cuprous iodide, tri-o-tolylphosphine / acetonitrile / 24 h / Heating 2: 78 percent / O3 / CH2Cl2; methanol / -78 °C 3: HCl / ethanol / 4 h / 70 °C View Scheme