sodium ethanolate in diethyl ether T=20°C; 3 h; Inert atmosphere;

1: |Inert atmosphere 2: copper (II) acetate monohydrate / o-xylene / 4 h / 135 °C / |Inert atmosphere 3: 4-(N,N-dimethlyamino)pyridine / dichloromethane / 1 h / 20 °C / |Inert atmosphere 4: sodium ethanolate / diethyl ether / 3 h / 20 °C / |Inert atmosphere View Scheme

palladium diacetate 1) AcOH, CCl4, 80 deg C, 2) 0 deg C, 18 h; add of THF in step 2); Yield given. Multistep reaction. Yields of byproduct given;