Abstract
UV irradiation of a number of N-alkenyl-substituted maleimide
derivatives leads to the formation of complex perhydroazaazulenes in
excellent yields. The overall process can be considered as a formal
intramolecular [5+2] cycloaddition. Substrates were prepared by
Mitsunobu coupling of the appropriate alkenols with various maleimides.
Methyl substitution of the alkenyl side chain gave the cycloadducts 13a−g in good yields, with moderate to high stereoselectivity being observed for 13e and 13g,
respectively. Use of cyclic alkene side chains led to the formation of
tri- and tetracyclic products with high degrees of stereoselectivity in
most cases. Some of the polycyclic ring systems that were prepared
constitute the core skeleton of a number of complex alkaloids. The
substrate 29 underwent an unexpected [2+2] photocycloaddition to yield the unusual cyclobutane 31.
Translated title of the contribution | Intramolecular Photocycloaddition of N-Alkenyl Substituted Maleimides: A Potential Tool for the Rapid Construction of Perhydroazaazulene Alkaloids |
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Original language | English |
Pages (from-to) | 1473-1482 |
Number of pages | 10 |
Journal | European Journal of Organic Chemistry |
Volume | 2001 |
Issue number | 8 |
Early online date | 9 Mar 2001 |
DOIs | |
Publication status | Published - 28 Apr 2001 |
Keywords
- Alkaloids
- Cycloadditions
- Maleimides
- Nitrogen heterocycles
- Photochemistry