title: Reactivity and synthesis inspired by the Zincke ring-opening of pyridines.
abstract: The century-old Zincke process for ring-opening of pyridinium salts produces 5-amino-2,4-pentadienals, a type of donor-acceptor dienes known as Zincke aldehydes. Inspired by this reasonably general and often efficient process for dearomatization, my laboratory has used pyridines as a starting point for heterocycle synthesis, which resulted in unusual syntheses of indoles, pyrrolines, and a formal synthesis of the natural product porothramycin A. Furthermore, our study of the reactivity of Zincke aldehydes has led to accidental discoveries of pericyclic cascade reactions that produce Z-α,β-unsaturated amides or polycyclic lactams, depending upon the identity of the substituents on nitrogen. Finally, a base-mediated formal cycloaddition reaction of tryptamine-derived Zincke aldehydes has served as the key step in concise syntheses of the indole alkaloids norfluorocurarine and strychnine.
authors.affiliation: 1102 Natural Sciences II, Department of Chemistry, University of California, Irvine, California 92697-2025, USA. cdv@uci.edu
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Vanderwal
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D003500:Cyclization; D006571:Heterocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D011725:Pyridines / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D006571:Heterocyclic Compounds; D011725:Pyridines