Tetrahedron

Palladium-catalyzed N-heteroannulation of N-allyl-or N-benzyl-2-nitrobenzenamines: synthesis of 2-substituted benzimidazoles

JW Hubbard, AM Piegols, BCG Söderberg

Index: Hubbard, Jeremiah W.; Piegols, Adam M.; Soederberg, Bjoern C.G. Tetrahedron, 2007 , vol. 63, # 30 p. 7077 - 7085

Full Text: HTML

Citation Number: 31

Abstract

In contrast, annulation to form a benzimidazole has only been reported in a single case using a ruthenium-catalyst and N-allyl 2-nitrobenzenamine (1) as the substrate. 8 Reaction of 1 using triruthenium dodecacarbonyl (7 mol %) at elevated temperature and carbon monoxide pressure gave 2-ethenylbenzimidazole 2 ( Scheme 1). It is interesting to note that both a higher yield of 2 and the formation of 2-methylquinoxaline (3) were observed using cyclooctene as the ...