1: 88 percent / HCOOH, Pd(OAc)2, PPh3 / tetrahydrofuran / 20 h / Heating 2: 17 percent / MS, BF3O*Et2 / CH2Cl2 / 2 h / -20 °C 3: 95 percent / NaOMe, MeOH / 0.75 h / Ambient temperature View Scheme