X=Y-ZH systems as potential 1,3-dipoles. Part 32 generation of nitrones from oximes. Tandem Michael addition-1,3-dipolar cycloaddition reactions. Background and class 1 processes.
1991; Elsevier BV; Volume: 47; Issue: 25 Linguagem: Inglês
10.1016/s0040-4020(01)87116-7
ISSN1464-5416
AutoresRonald Grigg, Frances Heaney, Sivagnanasundram Surendrakumar, W. J. WARNOCK,
Tópico(s)Fluorine in Organic Chemistry
ResumoIntermolecular Michael addition of aldoximes and ketoximes to electronegative olefins generates nitrones. The keto nitrones can be trapped in regiospecific intermolecular cycloaddition reactions giving single cycloadducts in good yield. Chemospecific 1:1:1 cycloadducts are obtained from ketoximes, monosubstituted electronegative olefins (Michael acceptor) and N-methylmaleimide (dipolarophile), whilst the chemoselectivity of the corresponding reactions with aldoximes is dependent on the oxime stereochemistry. Z-Aldoximes show high chemospecificity whilst E-aldoximes are much less chemoselective.
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