1: 84 percent / pyridinium chlorochromate / CH2Cl2 / 1.5 h / 25 °C 2: 80 percent / 1 N HCl / tetrahydrofuran / 2 h / 80 °C View Scheme

1: 84 percent / pyridinium chlorochromate / CH2Cl2 / 1.5 h / 25 °C 2: 80 percent / 1 N HCl / tetrahydrofuran / 2 h / 80 °C 3: 1.) Mg, 2.) CuBr*Me2S, Me2S / 1.) THF, 25 deg, 20 min, 2.) ether, from -78 deg C to 0 deg C, 18 h 4: 89 percent / 0.1 N HCl / tetrahydrofuran / 72 h / 25 °C View Scheme