titanium(IV) isopropylate; titanium tetrachloride in dichloromethane T=-78°C;

1: 94 percent / p-toluenesulphonic acid / benzene / Heating 2: 94 percent / CuI / diethyl ether 3: 85 percent / Br2 / acetic acid / 1) 0 deg C, 2) r.t. 4: 81 percent / CaCO3 / dimethylformamide / Heating View Scheme

toluene-4-sulfonic acid in benzene Heating;

1: 94 percent / p-toluenesulphonic acid / benzene / Heating 2: 94 percent / CuI / diethyl ether View Scheme

1: 94 percent / p-toluenesulphonic acid / benzene / Heating 2: 94 percent / CuI / diethyl ether 3: 85 percent / Br2 / acetic acid / 1) 0 deg C, 2) r.t. View Scheme