1: hex-5-ynoic acid chloride With indium(III) chloride in nitromethane Inert atmosphere; 2: ethanol in nitromethane Inert atmosphere;

1: 90 percent / pyridine; CH2Cl2 / 0 °C 2: 65 percent / Zn / acetic acid 3: 95 percent / diisobutylaluminum hydride / toluene / -78 °C 4: 72 percent / CH2Cl2 5: 63 percent / BaO / toluene / Heating; further reagent 6: Zn, AcOH / H2O / 70 °C 7: Na2CO3 / tetrahydrofuran / 0 °C 8: 87 percent / Ba(OH)2 / dioxane; H2O / Heating 9: SOCl2 / diethyl ether 11: 76 percent / NaBH4 / dimethylformamide / 80 °C 12: 85 percent / aq. HBr View Scheme

oxalyl dichloride; N,N-dimethyl-formamide in tetrahydrofuran T=20°C; 2 h; Inert atmosphere;

1: 82 percent / Jones' reagent / acetone / 1 h / Ambient temperature 2: 82 percent / oxalyl chloride, DMF / benzene / 2 h / 25 - 35 °C View Scheme

1: potassium hydroxide / methanol; H2O / Heating 2: thionyl chloride View Scheme

tin(IV) chloride in dichloromethane; benzene

pyridine in dichloromethane T=0°C; Yield given;

1.1: Mg; CuBr*DMS / tetrahydrofuran; diethyl ether / 0.5 h 1.2: 4.14 g / tetrahydrofuran / -40 - 20 °C 2.1: 59 percent / KHMDS / tetrahydrofuran; toluene / -78 - 20 °C 3.1: aq. HCl / tetrahydrofuran / 10 h / 20 °C View Scheme