1: With n-butyllithium in tetrahydrofuran; hexane T=-78°C; Inert atmosphere; 2: With boric acid trimethyl ester in tetrahydrofuran; hexane T=-78 - 20°C; Inert atmosphere; 3: With hydrogenchloride; water in tetrahydrofuran; hexane T=20°C; 0.5 h; Inert atmosphere;