Protonation of the isopropenylcyclopentadienyl anion : trapping of the isomer mixture with tetracyanoethylene

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Ray Lawson Hartless (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
David Knight

Abstract: The isomers obtained by protonation of the isopropenylcyclopentadienyl anion undergo reactions on standing which change the relative percentages of each isomer in the mixture. The suitability of tetracyanoethylene as a trapping agent is confirmed by the internal consistency of the relative percentages of the Diels-Alder adducts and isomers. Trapping of the isomer mixture with tetracyanoethylene yields three stable Diels-Alder adducts. The adducts were isolated by fractional crystallization and identified by their characteristic nuclear magnetic resonance, infrared spectra, and elemental analyses. The adducts and their relative percentages were: 7-isopropylidene- 5,5,6,6-tetracyanonorbornene (11.4 ± 2.0%), 2-isopropenyl- 5,5,6,6-tetracyanonorbornene (28.9 ± 1.3%), and 3a,6,6- trihydro-4,4,5,5-tetracyanoindene (58.5 ± 3.2%). Protonation of the anion yielded 17 ± 3% dimethylfulvene, 25 ± 2% 2-isopropenyl-l,3-cyclopentadiene, and 57 ± 2% 1-isopropenyl- l,3-cyclopentadiene.

Additional Information

Language: English
Date: 1971
Rearrangements (Chemistry)

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