1: 2-cyano-2-methylpiperidine-1-carboxylic acid tert-butyl ester With n-butyllithium; 1,10-phenanthroline; 4,4'-di(tert-butyl)-[1,1-biphenyl]yllithium in tetrahydrofuran; hexane T=-78°C; 0.0833333 h; 2: methyl chloroformate in tetrahydrofuran; hexane T=-78°C; 15 h;

1.1: 86 percent / tetrahydrofuran / 48 h 2.1: LDA; dimethylpropyleneurea / tetrahydrofuran; hexane / 1 h / -78 °C 2.2: 90 percent / tetrahydrofuran; hexane / 2 h / -78 °C 3.1: 1,10-phenanthroline; n-BuLi; lithium 4,4'-di-tert-butylbiphenylide / tetrahydrofuran; hexane / 0.08 h / -78 °C 3.2: 79 percent / tetrahydrofuran; hexane / 15 h / -78 °C View Scheme

1.1: 86 percent / tetrahydrofuran / 48 h 2.1: LDA; dimethylpropyleneurea / tetrahydrofuran; hexane / 1 h / -78 °C 2.2: 90 percent / tetrahydrofuran; hexane / 2 h / -78 °C 3.1: 1,10-phenanthroline; n-BuLi; lithium 4,4'-di-tert-butylbiphenylide / tetrahydrofuran; hexane / 0.08 h / -78 °C 3.2: 79 percent / tetrahydrofuran; hexane / 15 h / -78 °C View Scheme

1.1: LDA; dimethylpropyleneurea / tetrahydrofuran; hexane / 1 h / -78 °C 1.2: 90 percent / tetrahydrofuran; hexane / 2 h / -78 °C 2.1: 1,10-phenanthroline; n-BuLi; lithium 4,4'-di-tert-butylbiphenylide / tetrahydrofuran; hexane / 0.08 h / -78 °C 2.2: 79 percent / tetrahydrofuran; hexane / 15 h / -78 °C View Scheme

1: (+/-) methyl N-tert-butyloxycarbonyl 2-piperidinecarboxylate With lithium hexamethyldisilazane in tetrahydrofuran T=-78°C; 2: methyl iodide in tetrahydrofuran