thionyl chloride 1 h; Heating / reflux;

triethylamine in dichloromethane; trichlorophosphate

thionyl chloride

1: 74 percent / tetrahydrofuran / 30 min, -65 deg C, then room temperature 2: 1.) potassium t-butoxide / tetrahydrofuran, 1.) 30 min, 2.) 30 min 3: 11 percent / 5percent aqueous HCl / ethanol / 2 h / Heating View Scheme