sulfuric acid in tetrahydrofuran 48 h;

1: 96 percent / TsOH / benzene / 24 h / Heating 2: 1.) n-BuLi / 1.) THF, hexane, 0 deg C, 5 min, 2.) 10 min 3: 96 percent / NaH / tetrahydrofuran / 0.5 h / Ambient temperature 4: 85 percent / aq. H2SO4 / tetrahydrofuran / 48 h View Scheme

1: 1.) n-BuLi / 1.) THF, hexane, 0 deg C, 5 min, 2.) 10 min 2: 96 percent / NaH / tetrahydrofuran / 0.5 h / Ambient temperature 3: 85 percent / aq. H2SO4 / tetrahydrofuran / 48 h View Scheme

1: 1.) n-BuLi / 1.) THF, hexane, 0 deg C, 5 min, 2.) 10 min 2: 96 percent / NaH / tetrahydrofuran / 0.5 h / Ambient temperature 3: 85 percent / aq. H2SO4 / tetrahydrofuran / 48 h View Scheme

1: 96 percent / NaH / tetrahydrofuran / 0.5 h / Ambient temperature 2: 85 percent / aq. H2SO4 / tetrahydrofuran / 48 h View Scheme

1: 7 percent / NaH / tetrahydrofuran / 1 h / Heating 2: 1.) n-BuLi / 1.) THF, hexane, 0 deg C, 5 min, 2.) 10 min 3: 96 percent / NaH / tetrahydrofuran / 0.5 h / Ambient temperature 4: 85 percent / aq. H2SO4 / tetrahydrofuran / 48 h View Scheme