1: 63 percent / sec-butyllithium; bromine / cyclohexane; tetrahydrofuran / 0.75 h / -75 °C 2: 93 percent / 2,2,6,6-tetramethylpiperidine; butyllithium / hexane; tetrahydrofuran / 2 h / -75 °C 3: 90 percent / potassium hydroxide / methanol; H2O / 2 h / Heating 4: 98 percent / zinc / aq. NaOH / 2 h / 25 °C View Scheme

1: 71 percent / sec-butyllithium / cyclohexane; tetrahydrofuran / 0.75 h / -75 °C 2: 91 percent / potassium hydroxide / methanol; H2O / 2 h / Heating View Scheme

sec.-butyllithium in tetrahydrofuran; cyclohexane T=-75°C;

Me3SiCH2K in tetrahydrofuran T=-100°C;

2,2,6,6-tetramethylpiperidinyl-lithium in tetrahydrofuran T=-100°C;

N,N,N',N'',N''-pentamethyldiethylenetriamine; LiCH(CH3(C2H5 in diethyl ether T=-100°C;

1: 63 percent / sec-butyllithium; bromine / cyclohexane; tetrahydrofuran / 0.75 h / -75 °C 2: 93 percent / 2,2,6,6-tetramethylpiperidine; butyllithium / hexane; tetrahydrofuran / 2 h / -75 °C 3: 90 percent / potassium hydroxide / methanol; H2O / 2 h / Heating View Scheme

2,2,6,6-tetramethylpiperidinyl-lithium in tetrahydrofuran T=-100°C;

1.1: 63 percent / sec-butyllithium; bromine / cyclohexane; tetrahydrofuran / 0.75 h / -75 °C 2.1: 93 percent / 2,2,6,6-tetramethylpiperidine; butyllithium / hexane; tetrahydrofuran / 2 h / -75 °C 3.1: potassium carbonate; tributyltin hydride / 12 h / 60 °C 3.2: 74 percent / α,α'-azobis(isobutyronitrile) / benzene / 3 h / 60 °C 4.1: 91 percent / potassium hydroxide / ethanol; H2O / 2 h / 25 °C View Scheme

1: 63 percent / sec-butyllithium; bromine / cyclohexane; tetrahydrofuran / 0.75 h / -75 °C 2: 93 percent / 2,2,6,6-tetramethylpiperidine; butyllithium / hexane; tetrahydrofuran / 2 h / -75 °C View Scheme