A novel allylic substitution strategy to four-component synthesis of pyrazole-substituted fused pyrroles

The selective formation of pyrazole-substituted fused pyrroles through HOAc-mediated multicomponent reactions of enaminones with arylglyoxal monohydrates and generated in situ pyrazole-3-carboxylates was developed. It constructed a variety of bis-heterocyclic pairs under mild conditions in a domino process. Reaction driving tandem cyclization/allylic esterification/allylic substitution was achieved through the formation of in situ generation of allyl esters and pyrazole-3-carboxylates from readily available starting materials. Up to two new five-membered heterocyclic rings and five new sigma bonds including a C(sp3)–C(sp2) bond were formed in a single reaction without isolated intermediates.

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