Copper-Catalyzed Annulation of α,β-Unsaturated Ketoximes with Dialkyl Acetylenedicarboxylates for the Synthesis of Highly Substituted Pyridines

A copper-catalyzed [4 + 2] annulation protocol from readily available α,β-unsaturated ketoximes and dialkyl acetylenedicarboxylates has been achieved. The approach enables the expedient construction of a series of structurally new highly substituted pyridines with good functional group tolerance.