1: 98 percent / molecular sieves / CH2Cl2 / 12 h / Ambient temperature 2: 94 percent / NaBH3CN / ethanol / 0.5 h / Ambient temperature 3: 57 percent / TiCl4 / benzene / 0.17 h / Heating View Scheme

1: Et3N, 4 Angstroem molecular sieves / CH2Cl2 / 48 h / Ambient temperature 2: 95 percent / NaBH3CN / ethanol / 0.17 h / 0 °C 3: 80 percent / TiCl4 / benzene / 10 h / Heating 4: 90 percent / NaOEt / ethanol / 0.5 h / 0 °C View Scheme