1: BuLi / tetrahydrofuran / 1 h / -78 °C 2: TiCl4 / CH2Cl2 / 1.5 h / -78 °C 3: 64 percent / KOH/MeOH / 3 h / Heating 4: 61 percent / benzenesulfonyl chloride / pyridine / 24 h / 0 °C 5: 70 percent / hydrogen / Pd/C (10percent) / tetrahydrofuran / Ambient temperature View Scheme

1: BuLi / tetrahydrofuran / 1 h / -78 °C 2: TiCl4 / CH2Cl2 / 1.5 h / -78 °C 3: 64 percent / KOH/MeOH / 3 h / Heating 4: 61 percent / benzenesulfonyl chloride / pyridine / 24 h / 0 °C 5: 70 percent / hydrogen / Pd/C (10percent) / tetrahydrofuran / Ambient temperature 6: 77 percent / triphenylphosphine diethyl azodicarboxylate / tetrahydrofuran / 1.) 0 deg C, 1 h; 2.) room temp. 2 h View Scheme

1: BuLi / tetrahydrofuran / 1 h / -78 °C 2: TiCl4 / CH2Cl2 / 1.5 h / -78 °C 3: 64 percent / KOH/MeOH / 3 h / Heating 4: 61 percent / benzenesulfonyl chloride / pyridine / 24 h / 0 °C 5: 70 percent / hydrogen / Pd/C (10percent) / tetrahydrofuran / Ambient temperature View Scheme

Multi-step reaction with 2 steps 1: BuLi / tetrahydrofuran / 1 h / -78 °C2: TiCl4 / CH2Cl2 / 1.5 h / -78 °C