The alpha-effect in cyclic secondary amines: new scaffolds for iminium ion accelerated transformations

Nick Tomkinson, Achim Porzelle, Julie L. Cavill, Richard L. Elliott, Gareth Evans, Timothy J. K. Gibbs, Ian L. Jones, James A Platts

Research output: Contribution to journalArticle

25 Citations (Scopus)
78 Downloads (Pure)

Abstract

Five-membered secondary amine heterocycles containing an α-heteroatom were prepared and shown to be ineffective as catalysts for the iminium ion catalysed Diels–Alder reaction between cinnamaldehyde and cyclopentadiene. Their six-membered counterparts proved to be highly active catalysts. In stark contrast, the catalytic activity observed when comparing the non α-heteroatom cyclic amines proline methyl ester and methyl pipecolinate showed the five-membered ring amine was significantly more active. Concurrent density functional theoretical calculations suggest a rationale for the observed trends in reactivity, highlighting that LUMO activation through an iminium ion intermediate plays a key role in catalytic activity.
Original languageEnglish
Pages (from-to)9961
Number of pages9966
JournalTetrahedron
Volume65
DOIs
Publication statusPublished - 2009

Keywords

  • cyclic secondary amines
  • iminium ions
  • accelerated transformations

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  • Research Output

    • 25 Citations
    • 1 Chapter

    Organocatalysed transformations of alpha,beta-unsaturated carbonyl compoundsthrough iminium ion intermediates

    Tomkinson, N. & Rowley, J., 14 Nov 2012, Asymmetric Synthesis : More Methods and Applications. Christmann, M. & Brase, S. (eds.). Weinheim, p. 29-34 6 p.

    Research output: Chapter in Book/Report/Conference proceedingChapter

  • Cite this

    Tomkinson, N., Porzelle, A., Cavill, J. L., Elliott, R. L., Evans, G., Gibbs, T. J. K., Jones, I. L., & Platts, J. A. (2009). The alpha-effect in cyclic secondary amines: new scaffolds for iminium ion accelerated transformations. Tetrahedron, 65, 9961. https://doi.org/10.1016/j.tet.2009.10.009