The influence of distal substitution on the base-induced isomerization of long-chain terminal alkynes

Innus Mohammad, Ji Young Mun, Amber Onorato, Martha D. Morton, Abdullah I. Saleh, Michael B. Smith

Research output: Contribution to journalArticle

Abstract

When compared to a long-straight chain terminal alkyne, a long chain terminal alkyne with a distal isopropyl unit (isobranched) isomerizes about two times faster when treated with strong base under identical conditions, and appears to follow pseudo first order kinetics. In both cases, equilibration to a 95–97:5–3 mixture of terminal:internal alkyne accompanies isomerization. The difference in rate may be due to an unusual folding of both long-chain alkynes, bringing the distal substituent close to the carbon-carbon-triple bond moiety. The distal isopropyl moiety may provide unanticipated steric hindrance that disrupts such folding, making the propargylic proton more available for reaction with base.

Original languageEnglish (US)
Pages (from-to)4162-4165
Number of pages4
JournalTetrahedron Letters
Volume58
Issue number44
DOIs
StatePublished - Nov 1 2017

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Alkynes
Isomerization
Substitution reactions
Carbon
Protons
Kinetics

Keywords

  • Alkyne
  • Allene
  • Distal isobranch
  • Isomerization
  • Kinetics

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

Cite this

The influence of distal substitution on the base-induced isomerization of long-chain terminal alkynes. / Mohammad, Innus; Mun, Ji Young; Onorato, Amber; Morton, Martha D.; Saleh, Abdullah I.; Smith, Michael B.

In: Tetrahedron Letters, Vol. 58, No. 44, 01.11.2017, p. 4162-4165.

Research output: Contribution to journalArticle

Mohammad, Innus ; Mun, Ji Young ; Onorato, Amber ; Morton, Martha D. ; Saleh, Abdullah I. ; Smith, Michael B. / The influence of distal substitution on the base-induced isomerization of long-chain terminal alkynes. In: Tetrahedron Letters. 2017 ; Vol. 58, No. 44. pp. 4162-4165.
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