1: 98 percent / 4-(dimethylamino)pyridine / acetonitrile / 1 h / Ambient temperature 2: 38 percent / n-tributyltin hydride, 2,2'-azobis(2-methylpropionitrile) (AIBN) / toluene / 2.5 h / 100 °C 3: 75 percent / AcOH / methanol / 1 h / 100 °C View Scheme

acetic acid in methanol T=100°C; 1.25 h;