Copper-Catalyzed One-Pot Synthesis of Glycosylated Iminocoumarins and 3-Triazolyl-2-Iminocoumarins

Abstract

A general strategy was developed for the synthesis of glycosyl Iminocoumarins (5a-x) in a one-pot, copper-catalyzed multicomponent reaction involving a domino reaction of sulfonyl azides, sugar alkynes, and salicylaldehydes via ketenimine intermediate formation. Similarly, glycosyl 3-triazolyl-2-iminocoumarin derivatives (6a-o) have also been synthesized in a one-pot, three component condensation via tandem “CuAAC-aldol-cyclization-dehydration” sequence. In this event, a copper-catalyzed cycloaddition reaction between 2-azidoacetonitrile and Sugar alkynes furnished a triazole derivative in-situ and activated the neighboring methylene group, inducing an aldol-cyclization-dehydration sequence in the presence of a salicylaldehyde. The yields were very good in all reactions.