triethylamine; trichlorophosphate 1 h; Heating;

1: 51 percent / Et3N / toluene / 12 h / Heating 2: 16 percent / AlCl3 / CH2Cl2 / 12 h / Ambient temperature 3: 94 percent / POCl3, NEt3 / 1 h / Heating View Scheme