Pd(0)-Catalyzed Direct Inter- and Intramolecular C–H Functionalization of 4-Carboxyimidazoles

Abstract

The palladium-catalyzed arylation and alkenylation of N-substituted methyl imidazole-4-carboxylates are described through inter- and intramolecular pathways. Both direct C2–H and C5–H arylation and alkenylation proceed under Pd(0)/Cu(I) cooperative catalysis and Pd(0) catalysis, respectively, in low-polarity 1,4-dioxane solvent. The methodology gives access to C2 (hetero)aryl or alkenyl imidazoles as well as innovative C2- and C5-arylated fused imidazoles tricycles with a five- to seven-membered middle ring.