1: With n-butyllithium; diisopropylamine in tetrahydrofuran; hexane T=-78°C; 1.16667 h; 2: tert-butyl 4-oxo-piperidine-1-carboxylate; alpha-bromoacetonitrile With N,N,N',N',N'',N''-hexamethylphosphoric triamide T=20°C; 2 h;