trifluoroacetic acid T=-10°C; 0.25 h;

2,2'-azo-bisisobutyronitrile; tri-n-butyl-tin hydride; sodium iodide in ethylene glycol dimethyl ether 2 h; Heating;

1: 79 percent / n-BuLi, CuCN / diethyl ether / -70 - -50 °C 2: DIBAL-H / toluene / 3 h / -78 °C 3: toluene / 15 h / 23 °C 4: DMAP, Et3N / pyridine / 26 h / 45 °C 5: DIBAL-H / toluene / 1 h / -78 °C 6: CBr4, PPh3 / CH2Cl2 / 1 h 7: Ph3P / acetonitrile / 6 h 8: 62 percent / 1) n-BuLi / tetrahydrofuran; hexamethylphosphoric acid triamide / 1) -78 deg C, 1 h, 2) -78 to -50 deg C, 1.5 h 9: 90 percent / n-Bu4NF / tetrahydrofuran / 12 h 10: LiOH / tetrahydrofuran; H2O View Scheme