potassium carbonate in acetone Ambient temperature;

1: 92 percent / NaOMe, MeOH / 5 h / Ambient temperature 2: 1.) dibutyltin oxide / 1.) MeOH, reflux, 2 h, 2.) CH2Cl2, 0 deg C, 30 min 3: 91 percent / pyridine / CH2Cl2 / 5 h / 0 °C 4: 90 percent / thiourea / methanol / 2 h / Heating 5: 80 percent / 4A molecular sieves, N-iodosuccinimide, silver triflate / CH2Cl2; toluene / 0.17 h / 0 °C 6: 83 percent / NaOMe, MeOH / CH2Cl2 / 5 h / Ambient temperature View Scheme

methanol; sodium methylate 5 h; Ambient temperature;