in benzene T=20 - 25°C; 3 h;

tetrabutylammomium bromide; water; potassium carbonate; potassium hydrogencarbonate; toluene-4-sulfonic acid 1) EtOH, 6 h, reflux, 2) CH2Cl2, 4 h, 20-25 deg C; Yield given;

water in benzene T=80°C; 1 h; Yield given;