1: With sodium bis(2-methoxyethoxy)aluminium dihydride in toluene T=0°C; 1 h; 2: in toluene T=20°C; 7 h;

sodium tetrahydroborate in methanol T=0°C; 2 h;

1.1: n-butyllithium / tetrahydrofuran / 1 h / -78 °C 1.2: 71 percent / tetrahydrofuran / 2 h 2.1: 89 percent / NaBH4 / methanol / 2 h / 0 °C View Scheme

1.1: 77 percent / N-bromosuccinimide; pyridine / acetonitrile / 2 h / 0 °C 2.1: n-butyllithium / tetrahydrofuran / 1 h / -78 °C 2.2: 71 percent / tetrahydrofuran / 2 h 3.1: 89 percent / NaBH4 / methanol / 2 h / 0 °C View Scheme

oxygen; potassium carbonate T=80°C; P=750.075 Torr; 24 h; Schlenk techniqueGreen chemistry;

phosphorus tribromide in dichloromethane T=0°C; 12 h;