1: 159 mg / titanium(IV) bromide, ethyl acetate / CH2Cl2 / 4.5 h / Ambient temperature 2: 27 percent / p-toluenesulfonic acid monohydrate / CH2Cl2 / 26 h / Ambient temperature 3: 100 percent / sodium methoxide / methanol / Ambient temperature View Scheme

1: 159 mg / titanium(IV) bromide, ethyl acetate / CH2Cl2 / 4.5 h / Ambient temperature 2: 35 percent / p-toluenesulfonic acid monohydrate / CH2Cl2 / 18 h / Ambient temperature 3: sodium methoxide / methanol / 0.33 h / Ambient temperature View Scheme