A Versatile New Approach to Bridgehead Nitrogen Bearing Benzimidazolo-Quinazoline Hybrids: Facile 1,4-Dipolar Cycloaddition of Benzyne and N-(1H-Benzo[d]Imidazol-2-yl)-1-Phenylmethanimines

The development of versatile new routes to bridgehead nitrogen-bearing polycyclic aromatic systems having privileged scaffolds is a synthetic challenge for organic chemists. An efficient synthesis of benzo[4,5]imidazo[1,2-a]quinazoline derivatives bearing bridgehead nitrogen by the reaction of benzo[d]imidazol-2-amines, aldehydes, and ortho-silyl aryltriflate via 1,4-dipolar cycloaddition is reported under the optimized reaction conditions. The methodology provides easy access to fused benzimidazolo-quinazolines by sequential C–N and C–C bond formation through a one-pot reaction.