Étude de la stéréochimie de la réaction de cycloaddition dipolaire-1,3 de quelques 5-phényl-3,6-dihydro-2H-1,4-oxazin-2-ones avec les N-méthyl et N-phénylmaléimides

Autor:	Karin Monnier, Michel Jannin, Marek M. Kubicki, Marie-France Mercier, Gérard Schmitt, Bernard Laude
Rok vydání:	1995
Předmět:	Stereochemistry Chemistry Organic Chemistry Moiety General Chemistry Racemization Catalysis Cycloaddition Stereocenter
Zdroj:	Canadian Journal of Chemistry. 73:181-190
ISSN:	1480-3291 0008-4042
DOI:	10.1139/v95-027
Popis:	Six derivatives of 5-phenyl-3,4-dihydro-2H-1,4-oxazin-2-ones 1 were synthetized from α-amino acids. These compounds are precursors of six-membered cyclic azomethine ylids involving one stereocenter. The 1,3-dipolar species react with N-methyl and N-phenylmaleimides, leading diastereospecifically to cycloadducts where the approach of the dipolarophile occurs from the less hindered side of the 1,3-dipole and with the maleimido moiety in an exo position. Unfortunately, racemization was observed during the cycloaddition reaction, presumably owing to reversible imine–enamine transformation. Keywords: α-amino acids, cyclic azomethine ylids, diastereospecificity.
Databáze:	OpenAIRE
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