toluene-4-sulfonic acid in dichloromethane 2 h; Ambient temperature;

1: 1.) 1.5 M BuLi / 1.) THF/hexane, -30 deg C, 2.) THF/hexane, 2 h, room temperature 2: 97 percent / hydrogen / Lindlar-catalyst, 1,2-bis<(2-hydroxyethyl)thio>ethane / ethanol / 4 h / Ambient temperature 3: 65 percent / TsOH*H2O / CH2Cl2 / 2 h / Ambient temperature View Scheme

1: MgSO4, BF3*Et2O / 1 h / 5 °C 2: 1.) 1.5 M BuLi / 1.) THF/hexane, -30 deg C, 2.) THF/hexane, 2 h, room temperature 3: 97 percent / hydrogen / Lindlar-catalyst, 1,2-bis<(2-hydroxyethyl)thio>ethane / ethanol / 4 h / Ambient temperature 4: 65 percent / TsOH*H2O / CH2Cl2 / 2 h / Ambient temperature View Scheme

1: MgSO4, BF3*Et2O / 1 h / 5 °C 2: 1.) 1.5 M BuLi / 1.) THF/hexane, -30 deg C, 2.) THF/hexane, 2 h, room temperature 3: 97 percent / hydrogen / Lindlar-catalyst, 1,2-bis<(2-hydroxyethyl)thio>ethane / ethanol / 4 h / Ambient temperature 4: 65 percent / TsOH*H2O / CH2Cl2 / 2 h / Ambient temperature View Scheme

1: 1.) 1.5 M BuLi / 1.) THF/hexane, -30 deg C, 2.) THF/hexane, 2 h, room temperature 2: 97 percent / hydrogen / Lindlar-catalyst, 1,2-bis<(2-hydroxyethyl)thio>ethane / ethanol / 4 h / Ambient temperature 3: 65 percent / TsOH*H2O / CH2Cl2 / 2 h / Ambient temperature View Scheme

1: 97 percent / hydrogen / Lindlar-catalyst, 1,2-bis<(2-hydroxyethyl)thio>ethane / ethanol / 4 h / Ambient temperature 2: 65 percent / TsOH*H2O / CH2Cl2 / 2 h / Ambient temperature View Scheme

potassium hydroxide in ethanol; ethyl acetate