1: CrCl2 / N,N-dimethyl-acetamide / 5 °C 2: 90 percent / NaI / dimethylsulfoxide / 12 h / 50 °C 3: 84 percent / pyridine, PBr3 / diethyl ether / a) -25 to -20 deg C, b) to 25 deg C, c) 40 deg C View Scheme

1: 1) n-BuLi / 1) hexane, THF, -78 to 0 deg C, 2) hexane, THF, a) 15 to 30 deg C, b) 40 to 45 deg C, 2 h 2: 90 percent / NaI / dimethylsulfoxide / 12 h / 50 °C 3: 84 percent / pyridine, PBr3 / diethyl ether / a) -25 to -20 deg C, b) to 25 deg C, c) 40 deg C View Scheme

1: 90 percent / NaI / dimethylsulfoxide / 12 h / 50 °C 2: 84 percent / pyridine, PBr3 / diethyl ether / a) -25 to -20 deg C, b) to 25 deg C, c) 40 deg C View Scheme

1: 92 percent / dimethylsulfoxide / 20 h / 80 °C 2: 84 percent / p-toluenesulfonic acid / methanol / Ambient temperature 3: 82 percent / PBr3 / diethyl ether View Scheme

chromium dichloride in N,N-dimethyl acetamide T=5°C; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

chromium dichloride in N,N-dimethyl acetamide T=5°C; Yield given. Yields of byproduct given. Title compound not separated from byproducts;