1: boron trichloride / dichloromethane; n-heptane / 1 h / -78 - 20 °C 2: trichlorophosphate / acetonitrile / 0 - 20 °C / |Inert atmosphere 3: palladium 10 on activated carbon; hydrogen / ethyl acetate; ethanol / 4 h / 20 °C 4: pyridine / dichloromethane / 0 - 20 °C 5: tetrakis(triphenylphosphine) palladium(0); lithium chloride / tetrahydrofuran / 7 h / |Inert atmosphere; |Reflux 6: boron tribromide / dichloromethane / -78 - 0 °C View Scheme

1: boron trichloride / dichloromethane; n-heptane / 1 h / -78 - 20 °C 2: trichlorophosphate / acetonitrile / 0 - 20 °C / |Inert atmosphere 3: palladium 10 on activated carbon; hydrogen / ethyl acetate; ethanol / 4 h / 20 °C View Scheme

boron trichloride in n-heptane; dichloromethane T=-78 - 20°C; 1 h; regioselective reaction;

1: 91 percent / boron trichloride / CH2Cl2 / -78 - 20 °C 2: 75 percent / POCl3 / acetonitrile / 0 - 25 °C View Scheme