sodium nitrite Sandmeyer reaction;

pyridinium chlorochromate in dichloromethane T=20°C;

in dichloromethane

palladium diacetate; caesium carbonate; triphenylphosphine in N,N-dimethyl-formamide T=120°C; 24 h; Inert atmosphere;

carbon tetrabromide; triphenylphosphine in tetrahydrofuran T=20°C; 1 h;

sodium bromide in acetonitrile

1: 96 percent / DMSO; (COCl)2; Et3N / CH2Cl2 / -78 - 20 °C 2: 99 percent / HONH2*HCl; aq. NaOH / ethanol / 12 h / 23 °C 3: 87 percent / 2-chloro-1,3-dimethylimidazolium chloride; Et3N / CH2Cl2 / cooling View Scheme

2,2,6,6-tetramethyl-piperidine-N-oxyl; sodium hypochlorite; sodium chlorite in acetonitrile T=35°C; pH 6.7;

1.1: 97 percent / NaH / tetrahydrofuran / 0 - 20 °C 2.1: 87 percent / n-BuLi / tetrahydrofuran; hexane / -78 - 20 °C 3.1: 98 percent / PPh3 / CH2Cl2 / 0 - 20 °C 4.1: 86 percent / n-BuLi / tetrahydrofuran; hexane / -78 - 20 °C 5.1: Cp2ZrCl2; n-BuLi / tetrahydrofuran; hexane / -78 - 20 °C 5.2: 90 percent / CuCl / tetrahydrofuran; hexane / Heating 6.1: 96 percent / TBAF / tetrahydrofuran / 3 h / 20 °C 7.1: 75 percent / second generation Grubbs catalyst / CH2Cl2 / 16 h / 20 °C View Scheme

1.1: n-BuLi / tetrahydrofuran / -78 °C 1.2: 72 percent / tetrahydrofuran 2.1: 76 percent / PCC / CH2Cl2 / 6 h / 20 °C View Scheme