1: With titanium tetrachloride; triethylamine in dichloromethane T=38 - 39°C; 48 h; Inert atmosphere; 2: With hydrogenchloride in dichloromethane; tert-butyl methyl ether; water 3: With sodium hydrogencarbonate in dichloromethane; tert-butyl methyl ether; water Product distribution / selectivity;