1: SOCl2, pyridine / benzene / 0.17 h / 0 °C 2: 1.) piperidine, Et3N, 2.) POCl3 / 1.) CHCl3, RT, 20 min, 2.) 100 deg C, 30 min 3: 96 percent / K2CO3 / acetone / 16 h / Heating 4: 54 percent / BBr3 / CH2Cl2 / a) -78 deg C, 0.5 h, b) -78 to -20 deg C, 10 min View Scheme