1: caesium carbonate / acetonitrile / 5 h / |Reflux 2: nonafluoro-n-butanesulfonyl fluoride; N-ethyl-N,N-diisopropylamine; triethylamine tris(hydrogen fluoride) / tetrahydrofuran / 48 h / 20 °C 3: triethylsilane; palladium dichloride / ethanol / 20 - 98 °C / |Inert atmosphere 4: lithium borohydride / tetrahydrofuran; ethanol / 0 - 20 °C 5: sodium hydroxide / methanol / 20 - 120 °C / |Sealed tube View Scheme