1: CH3SO2Cl, Et3N / CH2Cl2 / 0.67 h / 0 °C 2: 95 percent / tetrahydrofuran / 12 h / Ambient temperature 4: 1.) CuCN 5: pyridinium p-toluenesulfonate (PPTS) / methanol; diethyl ether 6: CrO3, H+ 7: aq. HF / acetonitrile View Scheme

1: CH3SO2Cl, Et3N / CH2Cl2 / 0.67 h / 0 °C 2: 95 percent / tetrahydrofuran / 12 h / Ambient temperature View Scheme