1: 82 percent / Et3N / CH2Cl2 / 3 h 2: 2.) Li2CuCl4 / 1.) THF, 20 min, 2.) THF, a) -10 deg C, 3 h, b) RT, overnight 3: 78 percent / p-toluenesulphonic acid / methanol / 14 h / Ambient temperature 4: 66 percent / PCC / CH2Cl2 5: 69 percent / tetrahydrofuran / 4 h / 0 °C 6: 61 percent / PCC, NaOAc / CH2Cl2 View Scheme

1: 82 percent / Et3N / CH2Cl2 / 3 h 2: 57 percent / Li2CuCl4 / tetrahydrofuran / -10 °C 3: 1.) CBr4, 2.) Ph3P / 1.) CH2Cl2, RT, 10 min, 2.) CH2Cl2, RT, overnight 4: 56 percent / Li2CuCl4 / tetrahydrofuran / -10 °C 5: p-toluenesulphonic acid / methanol / 76 °C View Scheme

1: 82 percent / Et3N / CH2Cl2 / 3 h 2: 2.) Li2CuCl4 / 1.) THF, 20 min, 2.) THF, a) -10 deg C, 3 h, b) RT, overnight 3: 78 percent / p-toluenesulphonic acid / methanol / 14 h / Ambient temperature 4: 66 percent / PCC / CH2Cl2 View Scheme