1.1: 92 percent / thionyl chloride / CCl4 / 4 h / Heating 2.1: copper(I) cyanide / tetrahydrofuran; hexane / 0.25 h / 20 °C 2.2: 90 percent / boron trifluoride diethyl etherate / tetrahydrofuran; hexane / 0.5 h / -78 °C 3.1: 16 percent / potassium trimethylsilanoate / tetrahydrofuran / 25 h / 20 °C 4.1: sodium hydrogen carbonate; bromine / methanol; CCl4; H2O / 0.01 h / 20 °C 4.2: 63 percent / di-tert-butyl peroxyoxalate; diphenyl diselenide; tributyltin hydride / toluene / 2.5 h / 0 °C 5.1: 87 percent / 1,3-dicyclohexylcarbodiimide; 4-(dimethylamino)pyridine / dimethylformamide / 1.33 h / 20 °C View Scheme

1.1: 16 percent / potassium trimethylsilanoate / tetrahydrofuran / 25 h / 20 °C 2.1: sodium hydrogen carbonate; bromine / methanol; CCl4; H2O / 0.01 h / 20 °C 2.2: 63 percent / di-tert-butyl peroxyoxalate; diphenyl diselenide; tributyltin hydride / toluene / 2.5 h / 0 °C 3.1: 87 percent / 1,3-dicyclohexylcarbodiimide; 4-(dimethylamino)pyridine / dimethylformamide / 1.33 h / 20 °C View Scheme

4-(N,N-dimethlyamino)pyridine; dicyclohexyl-carbodiimide 1) CH2Cl2, 4 deg C, 15 min, 2) DMF, 35 min; Yield given. Multistep reaction;