1: BBr3 / CH2Cl2 / -78 up to 0 deg C 2: 98 percent / Cu(I)Cl / pyridine / 5 h / 55 - 60 °C / air 3: H2 / (R-R)-Me-DuPHOS / tetrahydrofuran / 20 - 25 °C / 3102.9 Torr View Scheme

1: BBr3 / CH2Cl2 / -78 up to 0 deg C 2: 98 percent / Cu(I)Cl / pyridine / 5 h / 55 - 60 °C / air 3: H2 / (R-R)-Me-DuPHOS / tetrahydrofuran / 20 - 25 °C / 3102.9 Torr View Scheme

boron tribromide in dichloromethane -78 up to 0 deg C;

1: BBr3 / CH2Cl2 / -78 up to 0 deg C 2: 98 percent / Cu(I)Cl / pyridine / 5 h / 55 - 60 °C / air View Scheme