Palladium(0)‐Catalyzed Alkynyl and Allenyl Iminium Ion Cyclizations Leading to 1,4‐Disubstituted 1,2,3,6‐Tetrahydropyridines

The biologically important title heterocyclic compounds can be synthesized by two methods based on the cyclization of alkynyl and allenyl iminium ions generated in situ in the presence of organometallic reagents (see scheme). Symmetrical and unsymmetrical tetrahydropyridines with diverse substituents R4 were prepared in a single step under mild conditions. R1=n-, sec-, tert-alkyl; R4=aryl, 1-alkenyl, alkyl, 1-alkynyl, B(pinacolato). Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2008/z800823_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.