Synthesis of Naphtho-Fused Imidazo[1,2-a]pyridines through Copper-Catalyzed Cascade Reactions

Abstract

A library of π-extended naptho-fused imidazo[1,2-a]pyridines were assembled by a copper-catalyzed cascade reaction using simple starting materials and mild reaction conditions. This protocol has high functional group tolerance and afforded the heterocyclic products in moderate to excellent yields (35–91 %). Photophysical studies show that these naphtho[1′,2′:4,5]imidazo[1,2-a]pyridines emit with high fluorescence quantum yields. EWG=electron-withdrawing group.