1: in hexanes; diethyl ether T=-78 - 20°C; 2.66667 h; Inert atmosphere; 2: With methanol in hexanes; diethyl ether T=-78 - 20°C; 0.5 h; 3: With perchloric acid in hexanes; diethyl ether T=20°C; 18 h; regiospecific reaction;