1.1: potassium tert-butoxide / tetrahydrofuran / 0.5 h / 0 °C 1.2: tetrahydrofuran / 12 h / 20 °C 1.3: 90 percent / formic acid / CH2Cl2 / 72 h / 20 °C 2.1: 95 percent / CH2Cl2 / 20 °C 3.1: NaBH4; BF3*OEt2 / tetrahydrofuran / 2 h / 20 °C 3.2: 90 percent / NaOH / H2O / 1 h / Heating 4.1: 82 percent / 120 °C 5.1: t-BuLi / diethyl ether; pentane / 0.17 h / -90 °C 5.2: 79 percent / Et2AlCl / hexane / -90 - 20 °C 6.1: PCC; NaOAc; 3A molecular sieves / CH2Cl2 / 48 h / 20 °C 6.2: 58 percent / KOH / tetrahydrofuran View Scheme

potassium carbonate; copper(II) oxide in pyridine T=150°C; 23 h;

sodium hydride; triphenylphosphine; zinc; NiCl2((PPh3)P)2 in toluene T=90 - 95°C; Ullmann-type coupling reaction; 12 h; Product distribution; Further Variations:Reagentsreaction time;

n-butyllithium; nitrobenzene 1.) THF, hexane, -75 deg C, 50 min.; 2.) -75 deg C, 4h, -> room temp.; Yield given. Multistep reaction;

1: 98 percent / NaBH4 / tetrahydrofuran; methanol / 2 h 2: SOCl2 / benzene / 20 °C 3: dimethylsulfoxide; benzene / 2 h 4: 92 percent / 4N NaOH / ethanol / 20 h / Heating 5: SOCl2 / benzene / 2 h / 50 - 60 °C 6: 91 percent / benzene; pyridine / 20 °C 7: 85 percent / POCl3 / toluene / 3 h / Heating 8: 100 percent / NaBH4 / methanol / 0.25 h 9: 75 percent / Pd(OAc)2; PPh3; K2CO3 / toluene / 26 h / Heating 10: 87 percent / LiAlH4 / tetrahydrofuran / 0.75 h / Heating View Scheme

n-butyllithium in tetrahydrofuran dissolved aromatic bromide in THF, added n-BuLi dropwise, mixt. stirredat -78°C for 15 min; added freshly distd. ((CH3)2CHO)3B, stirredat -78°C for 30 min, warmed to room temp., stirred for further 20 min; cooled to 0°C, acidified, extracted with CH2Cl2, dried, evapd. under vac.;

n-butyllithium in tetrahydrofuran dissolved aromatic bromide in THF, added n-BuLi dropwise, mixt. stirredat -78°C for 15 min; added freshly distd. (CH3O)3B, stirred at -78°C for 30 min, warmed to room temp., stirred for further 20 min; cooled to 0°C, acidified, extracted with CH2Cl2, dried, evapd. under vac.;

1: NaBH4 / methanol 2: 1.) NaH / 1.) DMF, 0 deg C, 2.) rt, 3 h 3: 1.) t-BuLi, 2.) methanol / 1.) THF, pentane, -100 to -95 deg C, 30 min, 2.) rt 4: methanol, trifluoroacetic acid / tetrahydrofuran; pentane / 36 h / Ambient temperature View Scheme

1: Amberlyst 15 / 1 h / Ambient temperature 2: BuLi / tetrahydrofuran / -100 deg C --> 20 deg C, overnight 3: Amberlyst-15 / acetone; H2O View Scheme

copper