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)

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.
LanguageEnglish
Pages9961
Number of pages9966
JournalTetrahedron
Volume65
DOIs
Publication statusPublished - 2009

Fingerprint

Scaffolds
Amines
Ions
Catalyst activity
Cyclopentanes
Catalysts
Cycloaddition Reaction
Proline
Density functional theory
Esters
Chemical activation
cinnamic aldehyde

Keywords

  • cyclic secondary amines
  • iminium ions
  • accelerated transformations

Cite this

Tomkinson, N., Porzelle, A., Cavill, J. L., Elliott, R. L., Evans, G., Gibbs, T. J. K., ... 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
Tomkinson, Nick ; Porzelle, Achim ; Cavill, Julie L. ; Elliott, Richard L. ; Evans, Gareth ; Gibbs, Timothy J. K. ; Jones, Ian L. ; Platts, James A. / The alpha-effect in cyclic secondary amines: new scaffolds for iminium ion accelerated transformations. In: Tetrahedron. 2009 ; Vol. 65. pp. 9961.
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Tomkinson, N, Porzelle, A, Cavill, JL, Elliott, RL, Evans, G, Gibbs, TJK, Jones, IL & Platts, JA 2009, 'The alpha-effect in cyclic secondary amines: new scaffolds for iminium ion accelerated transformations' Tetrahedron, vol. 65, pp. 9961. https://doi.org/10.1016/j.tet.2009.10.009

The alpha-effect in cyclic secondary amines: new scaffolds for iminium ion accelerated transformations. / Tomkinson, Nick; Porzelle, Achim; Cavill, Julie L.; Elliott, Richard L.; Evans, Gareth; Gibbs, Timothy J. K.; Jones, Ian L.; Platts, James A.

In: Tetrahedron, Vol. 65, 2009, p. 9961.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The alpha-effect in cyclic secondary amines: new scaffolds for iminium ion accelerated transformations

AU - Tomkinson, Nick

AU - Porzelle, Achim

AU - Cavill, Julie L.

AU - Elliott, Richard L.

AU - Evans, Gareth

AU - Gibbs, Timothy J. K.

AU - Jones, Ian L.

AU - Platts, James A

PY - 2009

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AB - 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.

KW - cyclic secondary amines

KW - iminium ions

KW - accelerated transformations

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JO - Tetrahedron

T2 - Tetrahedron

JF - Tetrahedron

SN - 0040-4020

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