Evidence for hydrogen abstraction by classical radicals in the norbornenyl-nortricyclyl system
Abstract
Studies of product compositions and deuterium-label rearrangements at various concentrations of tri-n-butyltin hydride in the reductions of exo- and endo-5-bromonorbornene and 2-bromonortricyclene to mixtures of norbornene and nortricyclene lead to three main conclusions: (i) at least two radical intermediates contribute to product formation; (ii) each intermediate yields predominantly (80% or more) one product; and (iii) nortricyclene is predominantly derived from a symmetrical intermediate. This constitutes strong evidence for hydrogen abstraction by classical (i.e., single-product) norbornenyl and nortricyclyl radicals. It is argued that the norbornenyl-nortricyclyl system is exceptionally well suited for the generation of a nonclassical (dual-product) radical; hence, the existence of a nonclassical radical in any other system is rather unlikely.
Additional Information
© 1971 by the National Academy of Sciences. Contributed by John D. Roberts, September 24, 1971. This work was supported by the National Science Foundation. Contribution no. 4336 from the Gates and Crellin Laboratories of Chemistry.Files
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- Eprint ID
- 7734
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- CaltechAUTHORS:HALpnas71
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2007-07-31Created from EPrint's datestamp field
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2021-11-08Created from EPrint's last_modified field