Polynaphthoquinone mediated metal-free direct N-alkylation of (hetero)aryl amines using alcohols

Abstract

Herein, we present polynaphthoquinone as an effective metal-free catalyst for the direct N-alkylation of aryl and heteroaryl amines using alcohols. Our experiments reveal that the optimal reaction conditions consist of 1.0 mmol of alcohol, 1.5 mmol of aniline, 0.8 equivalents of t-BuOK, and 30 wt% polynaphthoquinone catalyst in toluene at 135 °C under an inert atmosphere for 24 hours. Control experiments confirm that without a catalyst or base, the reaction fails to progress. Additionally, the reused catalyst in subsequent reactions yields good to excellent results. This methodology has also been extended to the dehydrogenative synthesis of quinolines and indoles.