in diethyl ether 1.) -95 deg C, 2.5 h, 2.) -60 deg C, 30 min.;

1: 80 percent / diethyl ether / 1.) -95 deg C, 2.5 h, 2.) -60 deg C, 30 min. 2: 100 percent / 1,1'-carbonyldiimidazol / toluene / 2 h / 115 °C / var.reag.: MsCl, Et3N, toluene, 2 h View Scheme

Multi-step reaction with 2 steps 1: 81 percent / diethyl ether / 1) -95 deg C, 2.5 h; 2) -60 deg C, 0.5 h2: 90 percent / N,N'-carbonyldiimidazole / toluene / 3 h / Heating  

Multi-step reaction with 2 steps 1: 85 percent / diethyl ether / 1.) -95 deg C, 2.5 h, 2.) -60 deg C, 30 min.2: 80 percent / MsCl, Et3N / 1 h / 25 °C