1: 50 percent / trifluoroacetic acid, triethylsilane / CH2Cl2 / 48 h / 40 °C 2: 67 percent / n-Bu4NBr, K2CO3 / 24 h / Heating 3: 1.) 20percent aq. NaOH, 2.) conc. HCl / 1.) ether, reflux, 24 h, 2.) ethyl acetate, 70 deg C, 4 h View Scheme