Relative rates and Arrhenius parameters for selected 1,2-arylmigrations and five- and six-member cyclizations of ortho-allybenzyl radical from reactions of halides and tri-N-butyltin hydride (poster session, 19th conference on reaction mechanisms)
The temperature dependent rates of radical rearrangements relative to abstraction of hydrogen atom from tri-n-butyltin hydride have been determined. The rearrangement of 2-phenyl-2-methylpropyl to 2-phenyl-1-methylpropyl (neophyl rearrangement) relative to hydrogen abstraction is represented by log r = 2.11 +- 0.02 - (7.35 +- 0.04)/theta, theta = 2.3 RT kcal/mole. The rearrangement of 0-allylbenzyl to 2-indanylmethyl exhibited log r = 2.52 +- 0.12 - (10.59 +- 0.25)/theta, and the rearrangement of 0-allylbenzyl to 2-tetralyl is represented by log r = 2.4 +- 0.2 - (11.6 +- 0.2)theta. The rearrangement of 1-indanylmethyl to 2-tetralyl is represented by log r = 2.24 +- 0.06 - (10.22 +- 0.11)/theta. The attempt to determine the cyclization rate of 0-vinyl-2-phenylethyl radical to 1-indanylmethyl and 1-tetralyl failed due to irreversible addition of tri-n-butyltin radical to the styrene double bond. However, kinetic closure to the five member ring was preferred over closure to the six member ring. From known or estimated rates of abstract of hydrogen from tri-n-butyltin hydride, rates or rearrangement of the three radicals are derived.
- Research Organization:
- Pacific Northwest Lab., Richland, WA (USA)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 5318443
- Report Number(s):
- PNL-SA-10522; CONF-820699-1; ON: DE82019211
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKYL RADICALS
ALLYL RADICALS
ARYL RADICALS
BUTYL RADICALS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDRIDES
HYDROGEN COMPOUNDS
HYDROGEN TRANSFER
ISOMERIZATION
KINETICS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANOMETALLIC COMPOUNDS
RADICALS
REACTION INTERMEDIATES
REACTION KINETICS
TEMPERATURE DEPENDENCE
TIN COMPOUNDS