1: With sec.-butyllithium in tetrahydrofuran; hexane T=-75°C; 2 h; 2: With bromine in tetrahydrofuran; hexane

(i) aq. HCl, aq. NaNO2, aq. HBF4, (ii) (heating); Multistep reaction;

1: N-methylpyrrolidone / 200 °C 2: SnCl2, HCl / diethyl ether View Scheme

1-methyl-pyrrolidin-2-one T=200°C;

2,2,6,6-tetramethyl-piperidine; n-butyllithium in tetrahydrofuran; hexane T=-75°C; 6 h;

1.1: 89 percent / 2,2,6,6-tetramethylpiperidine; butyllithium / tetrahydrofuran; hexane / 6 h / -75 °C 2.1: diisopropylamine; butyllithium / tetrahydrofuran; hexane / 2 h / -75 °C 2.2: 80 percent / iodine / tetrahydrofuran; hexane View Scheme