triethylamine in toluene T=150°C;

1: sodium dithionite / diethyl ether; tetrahydrofuran; H2O / 4 h / Heating 2: NaH / diethyl ether; tetrahydrofuran / 15 h / 23 °C 3: 73 percent / piperidine / tetrakis(triphenylphosphine)palladium(0), copper(I) iodide / 15 h / 100 °C 4: 87 percent / KF, H2O / dimethylformamide / 4 h / 23 °C 5: 44 percent / n-BuLi / tetrahydrofuran / 1.) -78 deg C, 1 h, 2.) 23 deg C, 48 h 6: 73 percent / cerium(IV) ammonium nitrate / acetonitrile; H2O / 0.5 h / 23 °C 7: 79 percent / 1,4-cyclohexadiene / benzene-d6 / 40 °C View Scheme

1: NaH / diethyl ether; tetrahydrofuran / 15 h / 23 °C 2: 73 percent / piperidine / tetrakis(triphenylphosphine)palladium(0), copper(I) iodide / 15 h / 100 °C 3: 87 percent / KF, H2O / dimethylformamide / 4 h / 23 °C 4: 44 percent / n-BuLi / tetrahydrofuran / 1.) -78 deg C, 1 h, 2.) 23 deg C, 48 h 5: 73 percent / cerium(IV) ammonium nitrate / acetonitrile; H2O / 0.5 h / 23 °C 6: 79 percent / 1,4-cyclohexadiene / benzene-d6 / 40 °C View Scheme

1: 73 percent / piperidine / tetrakis(triphenylphosphine)palladium(0), copper(I) iodide / 15 h / 100 °C 2: 87 percent / KF, H2O / dimethylformamide / 4 h / 23 °C 3: 44 percent / n-BuLi / tetrahydrofuran / 1.) -78 deg C, 1 h, 2.) 23 deg C, 48 h 4: 73 percent / cerium(IV) ammonium nitrate / acetonitrile; H2O / 0.5 h / 23 °C 5: 79 percent / 1,4-cyclohexadiene / benzene-d6 / 40 °C View Scheme

sulfuric acid

1.1: tetrahydrofuran; hexane / 0.17 h / -78 °C 1.2: n-BuLi / hexane 1.3: 94 percent / tetrahydrofuran; hexane / -78 - 20 °C 2.1: 100 percent / KOH / tetrahydrofuran; methanol; H2O / 1 h 3.1: 52 percent / Et3N / toluene / 150 °C View Scheme

1: 100 percent / KOH / tetrahydrofuran; methanol; H2O / 1 h 2: 52 percent / Et3N / toluene / 150 °C View Scheme

1: 36 percent / Et3N / toluene / 150 °C 2: 100 percent / MnO2 / CH2Cl2 / 20 °C View Scheme

1: 44 percent / n-BuLi / tetrahydrofuran / 1.) -78 deg C, 1 h, 2.) 23 deg C, 48 h 2: 73 percent / cerium(IV) ammonium nitrate / acetonitrile; H2O / 0.5 h / 23 °C 3: 79 percent / 1,4-cyclohexadiene / benzene-d6 / 40 °C View Scheme

1: 73 percent / cerium(IV) ammonium nitrate / acetonitrile; H2O / 0.5 h / 23 °C 2: 79 percent / 1,4-cyclohexadiene / benzene-d6 / 40 °C View Scheme