hydrogenchloride; titanium tetraethoxide; sodium hydroxide; sodium tetrahydroborate; chloro-(2-methylpropyl)magnesium; ammonium acetate; water; copper(I) bromide in tetrahydrofuran; methanol; tert-butyl methyl ether; toluene T=-78 - 20°C; 18 - 20 h; Heating / reflux;