Palladium catalysed aryl amination reactions in supercritical carbon dioxide

Abstract

Palladium catalysed C–N bond formation in supercritical carbon dioxide has been accomplished. Carbamic acid formation is avoided in part through the use of an N-silylamine as the coupling partner. Employing a catalyst system of Pd₂dba₃ (1 mol%) and 2-dicyclohexylphosphino-2′,4′,6′-triisopropyl-1,1′-biphenyl (X-Phos) (2 mol%) enabled the catalytic amination of aryl bromides and chlorides with N-silylanilines to be realised in excellent yield. Extension of the methodology to the N-arylation of N-silyldiarylamines, N-silylazoles and N-silylsulfonamides is reported.