potassium carbonate; 1,3-bis(2,6-diisopropylphenyl)imidazolinium chloride; N-heterocyclic carbene palladium in N,N-dimethyl acetamide T=130°C;

1,2-bis-(diphenylphosphino)ethane T=150°C; Cadogan cyclization; 5 h; Neat (no solvent)Inert atmosphere;

bis(η4-1,5-cyclooctadiene)-di-μ-methoxy-diiridium(I) in benzene T=40°C; Inert atmosphere;

triphenylphosphine in 1,2-dichloro-benzene 6 h; Heating;

1: Pd2(dba)3; NaO-t-Bu / dioxane / 45 °C 2: 87 percent / Pd(OAc)2; PCy3*HBF4; K2CO3 / N,N-dimethyl-acetamide / 130 °C View Scheme

1: Pd2(dba)3; NaO-t-Bu / dioxane / 45 °C 2: 87 percent / Pd(OAc)2; PCy3*HBF4; K2CO3 / N,N-dimethyl-acetamide / 130 °C View Scheme

oxygen; palladium diacetate; acetic acid in toluene T=120°C; 31 h;

1: bis-triphenylphosphine-palladium(II) chloride; potassium carbonate / N,N-dimethyl-formamide; water / 24 h / 80 °C / |Inert atmosphere 2: triethylamine; 4-(N,N-dimethlyamino)pyridine / dichloromethane / 24 h / 20 °C / |Inert atmosphere 3: copper diacetate; acetic acid; manganese(IV) oxide / N,N-dimethyl-formamide / 1 h / 200 °C / |Microwave irradiation; |Sealed tube View Scheme

1: bis-triphenylphosphine-palladium(II) chloride; potassium carbonate / N,N-dimethyl-formamide; water / 24 h / 80 °C / |Inert atmosphere 2: triethylamine; 4-(N,N-dimethlyamino)pyridine / dichloromethane / 24 h / 20 °C / |Inert atmosphere 3: copper diacetate; acetic acid; manganese(IV) oxide / N,N-dimethyl-formamide / 1 h / 200 °C / |Microwave irradiation; |Sealed tube View Scheme

1: 91 percent / K2CO3; Pd(PPh3)4 / toluene; H2O / 4 h / Heating 2: 85 percent / PPh3 / 1,2-dichloro-benzene / 6 h / Heating View Scheme