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

doi:10.1016/j.tet.2009.10.009

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

Pure And Applied Chemistry

Research output: Contribution to journal › Article › peer-review

26 Citations (Scopus)

84 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 language	English
Pages (from-to)	9961
Number of pages	9966
Journal	Tetrahedron
Volume	65
DOIs	https://doi.org/10.1016/j.tet.2009.10.009
Publication status	Published - 2009

Keywords

cyclic secondary amines
iminium ions
accelerated transformations

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10.1016/j.tet.2009.10.009

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26 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 proceeding › Chapter

Cite this

@article{6282faaa03594f808249c99651317240,

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

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.",

keywords = "cyclic secondary amines , iminium ions, accelerated transformations",

author = "Nick Tomkinson and Achim Porzelle and Cavill, {Julie L.} and Elliott, {Richard L.} and Gareth Evans and Gibbs, {Timothy J. K.} and Jones, {Ian L.} and Platts, {James A}",

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doi = "10.1016/j.tet.2009.10.009",

language = "English",

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pages = "9961",

journal = "Tetrahedron",

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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

Y1 - 2009

N2 - 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.

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

U2 - 10.1016/j.tet.2009.10.009

DO - 10.1016/j.tet.2009.10.009

M3 - Article

VL - 65

SP - 9961

JO - Tetrahedron

JF - Tetrahedron

SN - 0040-4020

ER -

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

Abstract

Keywords

Access to Document

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

Cite this