1.1: n-butyllithium / tetrahydrofuran; hexane / 0.5 h / -78 °C / |Inert atmosphere 1.2: 1 h / -78 - 20 °C / |Inert atmosphere 2.1: trifluoroacetic acid / dichloromethane / 1 h / 0 - 20 °C / |Inert atmosphere 3.1: palladium diacetate; oxygen / N,N-dimethyl acetamide / 120 °C View Scheme