1: 82 percent / DIBAH / CH2Cl2 / 0.5 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: 82 percent / DIBAH / CH2Cl2 / 0.5 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: 82 percent / DIBAH / CH2Cl2 / 0.5 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

trifluorormethanesulfonic acid in dichloromethane; cyclohexane 3.5 h; Ambient temperature;

triethylsilane; trimethylsilyl trifluoromethanesulfonate in dichloromethane T=20°C; 14 h;

trifluorormethanesulfonic acid in dichloromethane; cyclohexane T=10 - 20°C; Yield given. Title compound not separated from byproducts;

1: Et3N / tetrahydrofuran / 17 h / 20 °C 2: trimethylsilyl triflate; triethylsilane / CH2Cl2 / 14 h / 20 °C View Scheme

1: HCl / 2 h / Ambient temperature 2: 0.1 eq. triflic acid / CH2Cl2; cyclohexane / 10 - 20 °C View Scheme

1: 1) 2.4 eq. n-BuLi; 2) 1.4 M H2SO4 / 1) THF, -78 deg C; 2) from -20 deg C to room temperature 2: 1) 2 eq. dicyclohexylborane; 2) NaOH, H2O2 / 1) THF, 0 deg C; 2) 40-50 deg C 3: HCl / 2 h / Ambient temperature 4: 0.1 eq. triflic acid / CH2Cl2; cyclohexane / 10 - 20 °C View Scheme

1: 1.4 eq. R-Alpine-Borane / neat (no solvent) / 8 h / 0 - 20 °C 2: 1) 2.4 eq. n-BuLi; 2) 1.4 M H2SO4 / 1) THF, -78 deg C; 2) from -20 deg C to room temperature 3: 1) 2 eq. dicyclohexylborane; 2) NaOH, H2O2 / 1) THF, 0 deg C; 2) 40-50 deg C 4: HCl / 2 h / Ambient temperature 5: 0.1 eq. triflic acid / CH2Cl2; cyclohexane / 10 - 20 °C View Scheme