acetic anhydride 2 h; Heating;

sulfuric acid T=60°C; 2 h; Yield given;

1: n-butyllithium / hexane; tetrahydrofuran / 0.5 h / 0 °C 2: 70 percent aq. sulfuric acid / 2 h / 60 °C View Scheme

1: 90 percent / phosphoric tribromide / 0.5 h / 150 °C 2: 87 percent / H2; Et3N / Pd/C / methanol / 2 h / 25 °C / 760 Torr View Scheme

phosphorus oxytribromide T=150°C; 0.5 h;

1.1: 90 percent / phosphoric tribromide / 0.5 h / 150 °C 2.1: diisopropylamine; butyllithium / tetrahydrofuran; hexane / 2 h / -75 °C 2.2: 94 percent / tetrahydrofuran; hexane View Scheme

1.1: 90 percent / phosphoric tribromide / 0.5 h / 150 °C 2.1: diisopropylamine; butyllithium / tetrahydrofuran; hexane / 2 h / -75 °C 2.2: 98 percent / tetrahydrofuran; hexane / 2 h View Scheme

1.1: 90 percent / phosphoric tribromide / 0.5 h / 150 °C 2.1: diisopropylamine; butyllithium / tetrahydrofuran; hexane / 2 h / -75 °C 2.2: 98 percent / tetrahydrofuran; hexane / 2 h 3.1: 97 percent / BF3*OEt2 / CH2Cl2 / 24 h / 25 °C View Scheme

1.1: 90 percent / phosphoric tribromide / 0.5 h / 150 °C 2.1: diisopropylamine; butyllithium / tetrahydrofuran; hexane / 2 h / -75 °C 2.2: 98 percent / tetrahydrofuran; hexane / 2 h 3.1: 97 percent / BF3*OEt2 / CH2Cl2 / 24 h / 25 °C 4.1: butyllithium / tetrahydrofuran; diethyl ether; hexane / 6 h / -100 °C 4.2: 94 percent / tetrahydrofuran; diethyl ether; hexane View Scheme