Synthesis of Aminofuran-Linked Benzimidazoles and Cyanopyrrole-Fused Benzimidazoles by Condition-Based Skeletal Divergence

A condition-based
skeletal divergent synthesis was explored to
achieve skeletal diversity in two component condensation reaction.
Cyanomethyl benzimidazole was reacted with α-bromoketone under
thermal conditions to furnish 2-aminofuranyl-benzimidazoles, while
the same reaction afforded 3-cyano-benzopyrrolo-imidazoles under microwave
irradiation. Two nonequivalent nucleophilic centers on benzimidazole
moiety were manipulated elegantly by different reaction conditions
to achieve the skeletal diversity.