Facile Installation of amino functionality to phosphine oxides and quinoline oxides via direct C-H activation

Abstract

Organophosphorus containing aniline functionalities and quinolines containing amino functionalities are important structural motif in various area. Nevertheless, organophosphorus and quinoline substrates had no efficient C-N bond introducing method yet. In this paper, we developed direct C-H amidation processes of organophosphorus and quinolines using P or N-oxide as stepping stone. This procedure was successfully applied for the first time to the asymmetric reaction giving rise to P-stereogenic center based on mechanistic consideration. Also, a practical amidating reagents were developed for 8-aminoquinolines. This approach is highly convenient to perform under mild conditions on the gram scale. Facile deprotection of the synthetically versatile amidating groups was achieved under the Pd-catalyzed transfer hydrogenation conditions with simultaneous deoxygenation of quinoline N-oxides, thus yielding 8-aminoquinolines in excellent overall efficiency.