Amination of aryl chlorides and fluorides toward the synthesis of aromatic amines by palladium-catalyzed route or transition metal free way: Scopes and limitations

Abstract

This paper presents the application of zeolite (NaY) supported Pd and Cu catalysts in amination reactions of aryl chlorides. Using 0.1 mol% Pd, good yields could be achieved in the coupling of 4-chloroacetohphenone and piperidine after 6 h at 140 °C. In the second part, we demonstrate two different pathways for transition metal free amination of activated aryl chlorides and fluorides, and, respectively, non- and deactivated aryl chlorides. These reactions were performed with excellent yields in short reaction time without any transition metal catalyst under optimized reaction conditions. Activated aryl halides react smoothly using 2.1 equiv. amine without additional base whereas deactivated aryl halides require the use of a strong base (KO tBu) for high conversion. DFT calculations were performed to study the surprising influence of substitutents at the aromatic ring on selectivity in metal free aminations found in this work.