Factors Controlling the Diels–Alder Reactivity of Hetero-1,3-Butadienes

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

We have quantum chemically explored the Diels–Alder reactivities of a systematic series of hetero-1,3-butadienes with ethylene by using density functional theory at the BP86/TZ2P level. Activation strain analyses provided physical insight into the factors controlling the relative cycloaddition reactivity of aza- and oxa-1,3-butadienes. We find that dienes with a terminal heteroatom, such as 2-propen-1-imine (NCCC) or acrolein (OCCC), are less reactive than the archetypal 1,3-butadiene (CCCC), primarily owing to weaker orbital interactions between the more electronegative heteroatoms with ethylene. Thus, the addition of a second heteroatom at the other terminal position (NCCN and OCCO) further reduces the reactivity. However, the introduction of a nitrogen atom in the backbone (CNCC) leads to enhanced reactivity, owing to less Pauli repulsion resulting from polarization of the diene HOMO in CNCC towards the nitrogen atom and away from the terminal carbon atom. The Diels–Alder reactions of ethenyl-diazene (NNCC) and 1,3-diaza-butadiene (NCNC), which contain heteroatoms at both the terminal and backbone positions, are much more reactive due to less activation strain compared to CCCC.

Original languageEnglish
Pages (from-to)995-1004
Number of pages10
JournalChemistryOpen
Volume7
Issue number12
Early online date26 Nov 2018
DOIs
Publication statusPublished - Dec 2018

Fingerprint

Atoms
Nitrogen
Chemical activation
Acrolein
Imines
Cycloaddition
Density functional theory
Carbon
Polarization
1,3-butadiene
ethylene
N,N'-bis((2-chloroethyl)nitrosocarbamoyl)cystamine
diazene

Keywords

  • activation strain model
  • density functional calculations
  • hetero-Diels–Alder reaction
  • orbital interactions
  • reactivity

Cite this

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title = "Factors Controlling the Diels–Alder Reactivity of Hetero-1,3-Butadienes",
abstract = "We have quantum chemically explored the Diels–Alder reactivities of a systematic series of hetero-1,3-butadienes with ethylene by using density functional theory at the BP86/TZ2P level. Activation strain analyses provided physical insight into the factors controlling the relative cycloaddition reactivity of aza- and oxa-1,3-butadienes. We find that dienes with a terminal heteroatom, such as 2-propen-1-imine (NCCC) or acrolein (OCCC), are less reactive than the archetypal 1,3-butadiene (CCCC), primarily owing to weaker orbital interactions between the more electronegative heteroatoms with ethylene. Thus, the addition of a second heteroatom at the other terminal position (NCCN and OCCO) further reduces the reactivity. However, the introduction of a nitrogen atom in the backbone (CNCC) leads to enhanced reactivity, owing to less Pauli repulsion resulting from polarization of the diene HOMO in CNCC towards the nitrogen atom and away from the terminal carbon atom. The Diels–Alder reactions of ethenyl-diazene (NNCC) and 1,3-diaza-butadiene (NCNC), which contain heteroatoms at both the terminal and backbone positions, are much more reactive due to less activation strain compared to CCCC.",
keywords = "activation strain model, density functional calculations, hetero-Diels–Alder reaction, orbital interactions, reactivity",
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Factors Controlling the Diels–Alder Reactivity of Hetero-1,3-Butadienes. / Yu, Song; de Bruijn, Hans M.; Svatunek, Dennis; Hamlin, Trevor A.; Bickelhaupt, F. Matthias.

In: ChemistryOpen, Vol. 7, No. 12, 12.2018, p. 995-1004.

Research output: Contribution to JournalArticleAcademicpeer-review

TY - JOUR

T1 - Factors Controlling the Diels–Alder Reactivity of Hetero-1,3-Butadienes

AU - Yu, Song

AU - de Bruijn, Hans M.

AU - Svatunek, Dennis

AU - Hamlin, Trevor A.

AU - Bickelhaupt, F. Matthias

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