A direct pathway for the coupling of arenes and alkylamines via a heterogeneous zeolite-based photocatalyst

Abstract

The production of N,N-dialkyl arylamines is relevant for a range of high-value materials such as pharmaceuticals, agrochemicals and organic materials. In general, these molecules are assembled via multiple pre-functionalization steps of the aromatic compound and a subsequent cross-coupling with the arylamine under harsh conditions. In this manuscript, we develop a more sustainable and efficient method for the direct C–H amination of arenes and alkylamines using Ru(bipy)₃²⁺ entrapped in the supercages of a faujasite support (CBV-100). This creates a heterogeneous photocatalyst that can be used under visible light irradiation. Furthermore, the mesomeric and/or inductive effects of the substituent groups on the arene coupling partner are thoroughly investigated using Hammett plots, leading to a rationally guided solvent selection (HFIP or CH₃CN). Using reduced reaction temperatures (<0 °C) drastically improves the product yield, while suppressing the generation of side products.