n-butyllithium in tetrahydrofuran; hexane

oxalic acid in methanol 2.5 h; Heating;

1.1: 96 percent / oxalic acid dihydrate / aq. methanol / 2.5 h / Heating 2.1: 90 percent / K2CO3 / acetone / 2 h / Heating 3.1: 94 percent / KI; CuI / hexamethylphosphoric acid triamide / 3 h / 150 °C 4.1: 96 percent / CuI; i-Pr2NH / PdCl2(PPh3)2 / dimethylformamide / 1.5 h / 60 °C 5.1: 71 percent / K2CO3; CuCl2*2H2O; NaOAc / PdCl2(PPh3)2 / 48 h / 20 °C 6.1: 72 percent / BBr3 / CH2Cl2 / 30.5 h / -78 - -40 °C 7.1: KOH / tetrahydrofuran / 2 h / Heating 7.2: 53 percent / TsOH*H2O / tetrahydrofuran / 5 h / 60 °C View Scheme

1: With n-butyllithium in tetrahydrofuran; hexane T=-95°C; 0.0833333 h; 2: With iodine in tetrahydrofuran; hexane T=-95°C; Further stages.;

1: 96 percent / oxalic acid dihydrate / aq. methanol / 2.5 h / Heating 2: 90 percent / K2CO3 / acetone / 2 h / Heating 3: 94 percent / KI; CuI / hexamethylphosphoric acid triamide / 3 h / 150 °C 4: 96 percent / CuI; i-Pr2NH / PdCl2(PPh3)2 / dimethylformamide / 1.5 h / 60 °C 5: 81 percent / DIBAL-H / toluene; CH2Cl2 / 3 h / -78 °C 6: 67 percent / TBAF / tetrahydrofuran / 3 h / Heating 7: 78 percent / NaOMe / methanol / 20 h / Heating View Scheme