Base-promoted elimination reactions of (E)- and (Z)-arylaldehyde O-benzoyloximes. Effects of stereochemistry, β-aryl group, and base-solvent on the nitrile-forming transition states

Sang Yong Pyuna, Bong-Rae Cho

Research output: Contribution to journalArticle

Abstract

This account summarizes the results of mechanism studies on the nitrile-forming eliminations from (E)- and (Z)-arylaldehyde O-benzoyloximes promoted by 1,8-diazabicyclo-[5.4.0]undec-7- ene (DBU) in MeCN, R1R2NH in MeCN, and R1R2NH/R1R2NH2 + in 70mol% MeCN(aq). The rate of anti-elimination was 36,000-fold faster than that of syn-elimination. The change of the β- aryl group from Ph to thienyl to furyl shifted the E2 transition state slightly towards product-like. When (E)-2,4-dinitrobenzaldehyde O-benzoyloxime was employed as the reactant and R1R2NH/R1R2NH2 + in 70mol% MeCN(aq) was used as the base-solvent, the (E1cb)irr was observed.

Original languageEnglish
Pages (from-to)118-137
Number of pages20
JournalArkivoc
Volume2010
Issue number7
Publication statusPublished - 2010 Jul 15

Fingerprint

Nitriles
Stereochemistry
1,8-diazabicyclo(5.4.0)undec-7-ene
2,4-dinitrobenzaldehyde

Keywords

  • E1cb mechanism
  • E2 mechanism
  • Elimination
  • Transition state

ASJC Scopus subject areas

  • Organic Chemistry

Cite this

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title = "Base-promoted elimination reactions of (E)- and (Z)-arylaldehyde O-benzoyloximes. Effects of stereochemistry, β-aryl group, and base-solvent on the nitrile-forming transition states",
abstract = "This account summarizes the results of mechanism studies on the nitrile-forming eliminations from (E)- and (Z)-arylaldehyde O-benzoyloximes promoted by 1,8-diazabicyclo-[5.4.0]undec-7- ene (DBU) in MeCN, R1R2NH in MeCN, and R1R2NH/R1R2NH2 + in 70mol{\%} MeCN(aq). The rate of anti-elimination was 36,000-fold faster than that of syn-elimination. The change of the β- aryl group from Ph to thienyl to furyl shifted the E2 transition state slightly towards product-like. When (E)-2,4-dinitrobenzaldehyde O-benzoyloxime was employed as the reactant and R1R2NH/R1R2NH2 + in 70mol{\%} MeCN(aq) was used as the base-solvent, the (E1cb)irr was observed.",
keywords = "E1cb mechanism, E2 mechanism, Elimination, Transition state",
author = "Pyuna, {Sang Yong} and Bong-Rae Cho",
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T1 - Base-promoted elimination reactions of (E)- and (Z)-arylaldehyde O-benzoyloximes. Effects of stereochemistry, β-aryl group, and base-solvent on the nitrile-forming transition states

AU - Pyuna, Sang Yong

AU - Cho, Bong-Rae

PY - 2010/7/15

Y1 - 2010/7/15

N2 - This account summarizes the results of mechanism studies on the nitrile-forming eliminations from (E)- and (Z)-arylaldehyde O-benzoyloximes promoted by 1,8-diazabicyclo-[5.4.0]undec-7- ene (DBU) in MeCN, R1R2NH in MeCN, and R1R2NH/R1R2NH2 + in 70mol% MeCN(aq). The rate of anti-elimination was 36,000-fold faster than that of syn-elimination. The change of the β- aryl group from Ph to thienyl to furyl shifted the E2 transition state slightly towards product-like. When (E)-2,4-dinitrobenzaldehyde O-benzoyloxime was employed as the reactant and R1R2NH/R1R2NH2 + in 70mol% MeCN(aq) was used as the base-solvent, the (E1cb)irr was observed.

AB - This account summarizes the results of mechanism studies on the nitrile-forming eliminations from (E)- and (Z)-arylaldehyde O-benzoyloximes promoted by 1,8-diazabicyclo-[5.4.0]undec-7- ene (DBU) in MeCN, R1R2NH in MeCN, and R1R2NH/R1R2NH2 + in 70mol% MeCN(aq). The rate of anti-elimination was 36,000-fold faster than that of syn-elimination. The change of the β- aryl group from Ph to thienyl to furyl shifted the E2 transition state slightly towards product-like. When (E)-2,4-dinitrobenzaldehyde O-benzoyloxime was employed as the reactant and R1R2NH/R1R2NH2 + in 70mol% MeCN(aq) was used as the base-solvent, the (E1cb)irr was observed.

KW - E1cb mechanism

KW - E2 mechanism

KW - Elimination

KW - Transition state

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