1: With potassium tert-butylate in tetrahydrofuran T=-75 - -70°C; Inert atmosphere; 2: With hydrogenchloride; water in tetrahydrofuran T=-75 - -70°C; Inert atmosphere;

zinc in N,N-dimethyl-formamide 1 h; Irradiation;

in diethyl ether anhydr. ether, -40°C;