Selective cis-trans isomerization of a tetraene via an allene intermediate: Geometric isomerism via an sp/sup 2/ to sp/sup 2/ sigmatropic hydrogen shift and kinetic isotope effect studies
Journal Article
·
· J. Am. Chem. Soc.; (United States)
A kinetic investigation in the unlabeled and deuterium-labeled series of the (1,5) sigmatropic hydrogen shift of vinylallene 5 to trienes 7 plus 8 and the (1,7) sigmatropic hydrogen shift of dienallene 6 to tetraenes 9 plus 10 has been completed. The results lead to the proposal that the pathway for geometric isomerization of the terminal double bond of tetraene 9 involves as an intermediate the allene 6. The allene 6 could in fact be isolated in the case of the isomerization of 9, and moreover, at long reaction times 6 and 9 are transformed to 10. For the isomerization of 5 to 7 plus 8, it was shown that 7 and 8 interconvert with one another, but it is unclear whether allene 5 is an intermediate in their interconversion. The temperature dependencies of the primary deuterium kinetic isotope effects observed for the rearrangement of 5 (via a (1,5) sigmatropic hydrogen shift) and 6 (via the corresponding (1,7)-shift) suggest a tunneling contribution.
- Research Organization:
- Univ. of California, Riverside (USA)
- OSTI ID:
- 5845077
- Journal Information:
- J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 111:5; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ALLENE
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
DEUTERIUM
DIENES
EXPERIMENTAL DATA
HYDROCARBONS
HYDROGEN ISOTOPES
INFORMATION
ISOMERIZATION
ISOTOPE EFFECTS
ISOTOPES
KINETICS
LIGHT NUCLEI
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
POLYENES
REACTION INTERMEDIATES
REACTION KINETICS
STABLE ISOTOPES
STRUCTURAL CHEMICAL ANALYSIS
THERMODYNAMICS
400201* -- Chemical & Physicochemical Properties
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ALLENE
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
DEUTERIUM
DIENES
EXPERIMENTAL DATA
HYDROCARBONS
HYDROGEN ISOTOPES
INFORMATION
ISOMERIZATION
ISOTOPE EFFECTS
ISOTOPES
KINETICS
LIGHT NUCLEI
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
POLYENES
REACTION INTERMEDIATES
REACTION KINETICS
STABLE ISOTOPES
STRUCTURAL CHEMICAL ANALYSIS
THERMODYNAMICS