1: 65 percent / 1 N NaOH / 1 h / Heating 2: NaH / tetrahydrofuran / 64 h 3: acetic acid, 48percent HBr / 0.25 h / 100 °C 4: 71 percent / DIBAL-H / tetrahydrofuran; toluene / 2.5 h / -78 °C View Scheme

With  sodium hydroxide 1 h;  Heating;   

Multi-step reaction with 3 steps 1: 65 percent / 1 N NaOH / 1 h / Heating2: NaH / tetrahydrofuran / 64 h3: acetic acid, 48percent HBr / 0.25 h / 100 °C