I. Kinetic and mechanistic study of the (4+4) dimerization of 2,3-dimethylene-2,3-dihydrofuran. II. Preparation of 2,3-dimethylene-2,3-dihydrobenzo(B)furan by the flash vacuum pyrolysis of 2-methyl-3-benzo(B)furylmethyl benzoate. III. Reaction of 2,3-dimethylene-2,3-dihydrofuran with triplet oxygen
A kinetic and mechanistic study of the (4+4) dimerization of 2,3-dimethylene-2,3-dihydrofuran (1) has been carried out based on the secondary deuterium kinetic isotope effects (2/sup 0/D KIE), substituent effects and solvent effects. The 2/sup 0/D KIE was studied by measuring the rate constants, k/sub 1/, k/sub 2/, k/sub 3/, and K/sub 4/, respectively, for the (4+4) dimerization of 1,2-methylene-3-dideuteriomethylene-2,3-dihydrofuran (2), 2-dideuteriomethylene-3-methylene-2,3-dihydrofuran (3) and 2,3-bis(dideuteriomethylene)-2,3-dihydrofuran (4). The relation among k/sub 1/-k/sub 4/ at -30.0/sup 0/C was found to be k/sub 2//k/sub 1/ = k/sub 4//k/sub 1/ = 1.86 and k/sup 1/ = k/sub 3/. This result and the insignificant solvent effects that have been observed lead to the conclusion that the (4+4) dimerization of 1 proceeds via stepwise mechanism involving a diradical intermediate. 2,3-Dimethylene-2,3-dihydrobenzo(b)furan (5) was synthesized by the flash vacuum pyrolysis of 2-methyl-3-benzo(b)furylmethyl benzoate. The chemical reactions of 5, which were investigated in this study, include thermal dimerization reactions and Diels-Alder reactions. The dimerization reaction of 5 gave both (4+2) and (4+) dimers. The formation of cyclic peroxides from the reactions of 1 and its 5-methyl and 5-tert-butyl derivatives with triplet oxygen was investigated. Thermolysis of a cyclic peroxide gave dialdehyde, hydroxyl aldehyde and diol as the products.
- Research Organization:
- Iowa State Univ. of Science and Technology, Ames (USA)
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 6036372
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALKENES
DIMERIZATION
DEUTERIUM
ISOTOPE EFFECTS
FURANS
CHEMICAL REACTION KINETICS
TRACER TECHNIQUES
CHEMICAL REACTIONS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYDROGEN ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
POLYMERIZATION
REACTION KINETICS
STABLE ISOTOPES
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)
400302 - Organic Chemistry- Isotope Effects- (-1987)