Transition-metal catalyzed rearrangements in cyclobutene systems
- UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
- Kevin Cann (Creator)
- Institution
- The University of North Carolina at Greensboro (UNCG )
- Web Site: http://library.uncg.edu/
- Advisor
- James Barborak
Abstract: Transition-metal catalyzed rearrangements of substituted cyclobutene systems have been observed by various workers to proceed in a symmetry "forbidden" manner, suggesting either that the electronic constraints which govern such reactions are relaxed or reversed. Systems which have been used previously to probe the mechanism of such reactions have suffered from formidably high-energy transition states, involving for example trans-double bonds within six-membered rings. The present study was initially intended to investigate the mechanism of rearrangement of cyclobutenes by transition metals in systems in which both symmetry "allowed" and symmetry "forbidden" reaction products were energetically attainable. In the course of this study, however, a much more facile rearrangement pathway was discovered, which involved hydrogen migration rather than the ring-opening observed in earlier studies. The reaction appears to involve a mechanism not previously observed. Bicyclo[4.2.0] oct-7-ene and bicyclo[6.2.0] dec-9-ene rearrange essentially quantitatively and at high reaction rates to products which possess the same carbon framework, but in which the double bond has shifted to a thermodynamically more stable position.
Transition-metal catalyzed rearrangements in cyclobutene systems
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Created on 1/1/1975
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Additional Information
- Publication
- Thesis
- Language: English
- Date: 1975
- Subjects
- Transition metal catalysts
- Chemical reactions