Synthesis of fused bicyclic imidazoles by ring-closing metathesis

The preparation of a number of dienylimidazole via chemoselective metal–halogen exchange and their utility in ring-closing metathesis is described. Essentially all regioisomeric permutations participate in metathesis with the notable exception of 4-vinyl-5-allylimidazoles, provided that the imidazole N3 atom is protonated.