pyridine; phosphorus tribromide in diethyl ether; Petroleum ether T=-15°C; 1 h;

1.1: n-butyllithium / tetrahydrofuran; hexane / 15 h / 0 °C 1.2: 0 - 20 °C 2.1: lithium aluminium tetrahydride / diethyl ether / 0 °C 3.1: phosphorus tribromide / diethyl ether / 0.17 h / -30 °C View Scheme

1: diisobutylaluminium hydride / dichloromethane / 3 h / -78 - 20 °C 2: phosphorus tribromide; pyridine / hexane / 3 h / 20 °C / |Cooling with ice View Scheme