A Versatile Cascade of Intramolecular Vilsmeier−Haack and Azomethine Ylide 1,3-Dipolar Cycloaddition toward Tricyclic Cores of Alkaloids

In the pursuit of synthetic efficiency, we developed an innovative one-pot transformation of linear substrates into bi- and tricyclic adducts using a cascade of amide activation, nucleophilic cyclization, azomethine ylide generation, and subsequent inter- or intramolecular 1,3-dipolar cycloaddition. Despite the high density and variety of functional groups on the substrates, the sequence occurred with perfect chemoselectivity with good to excellent yields.