trifluoroacetic acid in chloroform-d1 3.5 h;

titanium tetrachloride in dichloromethane 1.) 85 min, 0 deg C, 2.) 35 min, 20 deg C; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

titanium tetrachloride in dichloromethane 1.) 85 min, 0 deg C, 2.) 35 min, 20 deg C; Yield given. Yields of byproduct given. Title compound not separated from byproducts;