1: dimethylformamide / 17 h / Heating 2: aq. H2SO4 / 2 h / Heating View Scheme

n-butyllithium 1) hexane, a) Et2O, 2 min, -78 deg C. b) THF, 60 min, -78 deg C. 2) ether; Yield given. Multistep reaction. Yields of byproduct given;

1.1: magnesium; iodine / tetrahydrofuran / 3 h / 25 °C / |Inert atmosphere 2.1: 2 h / 25 °C / |Inert atmosphere 3.1: palladium 10 on activated carbon; hydrogen / ethanol / 5 h / 25 °C 3.2: pH 5 - 6 View Scheme

1: dimethylformamide / 17 h / Heating 2: aq. H2SO4 / 2 h / Heating 3: (COCl)2, DMF / CH2Cl2 View Scheme

1: dimethylformamide / 17 h / Heating 2: aq. H2SO4 / 2 h / Heating 3: (COCl)2, DMF / CH2Cl2 4: tetrahydrofuran View Scheme

in N,N-dimethyl-formamide 17 h; Heating; Yield given;

1.1: 1,1-dibromomethane; magnesium / tetrahydrofuran / 20 °C 1.2: 2.5 h / 0 - 20 °C 2.1: sodium hydroxide / water; methanol / 1 h 3.1: ammonium chloride / water; methanol / 3 h / 50 °C 4.1: sodium hydroxide; dihydrogen peroxide / water; methanol / 6 h / 20 - 70 °C / Reflux View Scheme

n-butyllithium 1) hexane, a) Et2O, 2 min, -78 deg C. b) THF, 60 min, -78 deg C. 2) ether; Yield given. Multistep reaction. Yields of byproduct given;

1.1: isopropylmagnesium chloride / tetrahydrofuran / 2 h / -15 - 20 °C / Inert atmosphere 2.1: copper(l) iodide / tetrahydrofuran / 3 h / -20 - -15 °C / Inert atmosphere 3.1: sodium iodide; sodium azide / N,N-dimethyl-formamide / 16 h / 70 °C / Inert atmosphere 4.1: triphenylphosphine / acetonitrile / 13.5 h / 20 - 70 °C 4.2: 2 h 5.1: 18-crown-6 ether; ammonium chloride / dimethyl sulfoxide / 2 h / 80 °C 6.1: potassium hydroxide / ethanol; water / 12 h / 80 °C 6.2: 20 °C View Scheme

1: 1) lithium diisopropylamide / 1) THF, -78 deg C, 1 h, 2) up to room temp. 2: 1) lithium diisopropylamide / 1) THF, -78 deg C, 1 h, 2) up to 0 deg C 3: 1) 2.3 M n-BuLi / 1) ether, -78 deg C, 5 min, 2) ether, up to room temp. 4: 89 percent / CsF / acetonitrile / Ambient temperature View Scheme