1: 90 percent / ZnCl2, DIBAL / tetrahydrofuran / 1 h / -78 °C 2: 65 percent / Al-Hg / tetrahydrofuran; H2O / 12 h / Ambient temperature 3: 1.) Me3OBF4 2.) K2CO3 / 1.) MeNO2, 0 deg C, 1 h 2.) CH2Cl2, MeOH/H2O, r. t. 4: tetrahydrofuran / 6 h View Scheme