Aza-[3 + 3] Annulations: A New Unified Strategy in Alkaloid Synthesis

Title: Aza-[3 + 3] Annulations: A New Unified Strategy in Alkaloid Synthesis

Volume: 7 Issue: 4

Author(s): Grant S. Buchanan, John B. Feltenberger and Richard P. Hsung

Affiliation:

Keywords: Alkaloid synthesis, Aza-[3 + 3] annulation, Formal cycloaddition, Heterocycle, A unified synthetic strategy

Abstract: An aza-[3 + 3] annulation or formal cycloaddition strategy for constructing complex heterocycles, chiefly alkaloids, is reviewed here. This annulation involves a Knoevenagel-type condensation of α,β-unsaturated iminium salts with vinylogous amides or urethanes followed by a 6π-electron electrocyclic ring-closure. Both the inter- and intramolecular aza-annulation pathways illustrated here constitute a stepwise formal [3 + 3] cycloaddition in which two -bonds are formed in addition to a new stereogenic center adjacent to the heteroatom. This review describes our total synthesis efforts in the last ten years to unequivocally demonstrate that this aza-[3 + 3] annulation can serve as a powerful approach and a unified strategy in alkaloid synthesis.

Cite this article as:

S. Buchanan Grant, B. Feltenberger John and P. Hsung Richard, Aza-[3 + 3] Annulations: A New Unified Strategy in Alkaloid Synthesis, Current Organic Synthesis 2010; 7 (4) . https://dx.doi.org/10.2174/157017910791414490