Intramolecular cycloaddition of azomethine ylides in the preparation of pyrrolidino[2′,3′:3,4]pyrrolidino[1,2-a]benzimidazoles

The parent pyrrolidino[2',3':3,4]pyrrolidino[1,2-a]benzimidazole heterocycle as well as a series of novel analogues have been synthesized utilizing a microwave-assisted intramolecular cycloaddition of azomethine ylides as the key transformation. A variety of diversity groups were added to explore the scope of this reaction and to provide a number of new compounds for biological screening.