1: With N,N,N',N'',N''-pentamethyldiethylenetriamine; sec.-butyllithium in tetrahydrofuran; cyclohexane T=-78°C; 0.0166667 h; Inert atmosphere; 2: With chloro-trimethyl-silane in tetrahydrofuran; cyclohexane T=-78°C; 1 h; Inert atmosphere;