1: DIBALH / CH2Cl2 / 0.42 h / -5 - 0 °C 2: acetic acid 3: 82 percent / BF3*Et2O / CH2Cl2 / 1 h View Scheme

With  diisobutylaluminium hydride in  dichloromethane T=-5 - 0°C; 0.416667 h;   

Multi-step reaction with 2 steps 1: 71 percent / NaNO2, n-propyl nitrite / dimethylsulfoxide / 1.5 h / 50 - 52 °C2: 77 percent / dimethylsulfoxide / 0.42 h