formic acid; triethylamine; triphenylphosphine; palladium diacetate in N,N-dimethyl-formamide T=60 - 70°C; 0.5 h;

palladium on activated charcoal T=300 - 330°C;

palladium on activated charcoal T=300 - 330°C;

palladium on activated charcoal T=300 - 330°C;

copper in quinoline T=220 - 230°C;

1: 90 percent / 2,6-lutidine / CH2Cl2 / 0.5 h / 20 °C 2: 85 percent / PPh3; Et3N; HCO2H / Pd(OAc)2 / dimethylformamide / 0.5 h / 60 - 70 °C View Scheme

1: 64 percent / aq. Na2CO3 / Pd(PPh3)4 / 1,2-dimethoxy-ethane; ethanol / 12 h / Heating 2: 80 percent / LDA / tetrahydrofuran / 0.5 h / 20 °C 3: 90 percent / 2,6-lutidine / CH2Cl2 / 0.5 h / 20 °C 4: 85 percent / PPh3; Et3N; HCO2H / Pd(OAc)2 / dimethylformamide / 0.5 h / 60 - 70 °C View Scheme

1: 80 percent / LDA / tetrahydrofuran / 0.5 h / 20 °C 2: 90 percent / 2,6-lutidine / CH2Cl2 / 0.5 h / 20 °C 3: 85 percent / PPh3; Et3N; HCO2H / Pd(OAc)2 / dimethylformamide / 0.5 h / 60 - 70 °C View Scheme

1.1: S-BuLi; TMEDA / tetrahydrofuran / 1 h / -78 °C 1.2: B(OMe)3 / tetrahydrofuran / 20 °C 2.1: 2.21 g / MgSO4 / CH2Cl2 / 12 h 3.1: 64 percent / aq. Na2CO3 / Pd(PPh3)4 / 1,2-dimethoxy-ethane; ethanol / 12 h / Heating 4.1: 80 percent / LDA / tetrahydrofuran / 0.5 h / 20 °C 5.1: 90 percent / 2,6-lutidine / CH2Cl2 / 0.5 h / 20 °C 6.1: 85 percent / PPh3; Et3N; HCO2H / Pd(OAc)2 / dimethylformamide / 0.5 h / 60 - 70 °C View Scheme

2,3-dicyano-5,6-dichloro-p-benzoquinone in benzene