1: 91 percent / tetrahydrofuran / 0.75 h / Ambient temperature 2: 1.) PPh3, Pd(OAc)2, aq. Na2CO3 / 1.) DME, room temperature, 1 h, 2.) DME, reflux 3: 98 percent / POCl3 / acetonitrile / 0.5 h / Heating View Scheme

palladium diacetate; sodium carbonate; triphenylphosphine in ethylene glycol dimethyl ether Heating;