Dihydropyrans from 1,4-cycloaddition of enamines to arylmethylenepyrazolones. Polar character of the thermal rearrangement of the resulting cycloadducts

Article abstract of DOI:10.1080/00397919108021047

The inverse electron demand hetero-Diels-Alder reaction of arylmethylenepyrazolones with enamines results in the selective formation of 3,4-dihydro-2H-pyran derivatives. These cycloadducts under thermodynamic conditions, are transformed via the zwitterion, which can be captured in the presence of tetracyanoethylene (TCE), as the more stable Michael-type adducts. The zwitterion could also be the intermediate for the cyclic adducts.

Full text of DOI:10.1080/00397919108021047

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Dihydropyrans from 1,4-
Cycloaddition of Enamines to
Arylmethylenepyrazolones.
Polar Character of the Thermal
Rearrangement of the Resulting
Cycloadducts
M. Abdel-Rahman a & H. Abdel-Ghany a
a Chemistry Department, Faculty of Science , Assiut
University , Sohag, Egypt
Published online: 16 Feb 2007.
To cite this article: M. Abdel-Rahman & H. Abdel-Ghany (1991) Dihydropyrans from
1,4-Cycloaddition of Enamines to Arylmethylenepyrazolones. Polar Character of the
Thermal Rearrangement of the Resulting Cycloadducts, Synthetic Communications:
An International Journal for Rapid Communication of Synthetic Organic Chemistry,
21:10-11, 1281-1291, DOI: 10.1080/00397919108021047
To link to this article: http://dx.doi.org/10.1080/00397919108021047
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