1: 83 percent / diethyl phosphorocyanidate, Et3N / dimethylformamide / 2 h / 0 °C 2: 100 percent / aq. KOH / methanol / 10 h / Heating 3: 87 percent / NBS / dimethylformamide / 24 h / Ambient temperature 4: 6N aq. HCl / 12 h / Heating 5: diethyl ether 6: 98 percent / K2CO3 / 6 h / Ambient temperature View Scheme

1: 83 percent / diethyl phosphorocyanidate, Et3N / dimethylformamide / 2 h / 0 °C 2: 100 percent / aq. KOH / methanol / 10 h / Heating 3: 87 percent / NBS / dimethylformamide / 24 h / Ambient temperature 4: 6N aq. HCl / 12 h / Heating 5: diethyl ether 6: 98 percent / K2CO3 / 6 h / Ambient temperature 7: 94 percent / Ph3P, diethylazodicarboxylate / tetrahydrofuran / 2 h / Ambient temperature View Scheme