Search

Toluquinone-cyclopentadiene Diels-Alder epoxide adducts react with sulfur and oxygen nucleophiles under heterogeneous conditions, leading to products resulting from the epoxide ring opening and from skeletal rearrangement, respectively. Pyrolysis of the sulfanyl adducts gave the new 3-sulfanyltoluquinones (1). Key words: toluquinone, phase-transfer catalysis (PTC) conditions, thiolation, epoxide, Diels-Alder. Les epoxydes des adduits de Diels-Alder de la toluquinone et du cyclopentadiene reagissent avec des nucleophiles sulfures et oxygenees, dans des conditions heterogenes pour conduire respectivement a des produits resultats d'une ouverture de l'epoxyde et d'une transposition du squelette. La pyrolyse des adduits sulfanyles conduit aux nouvelles 3sulfanyltoluquinones (1). Mots-cles: toluquinone, conditions de transfert catalytique de phase (TCP), epoxyde, Diels-Alder. [Traduit par la Redaction], Introduction Quinones occur widely in nature as important components of organisms. (1) Natural and synthetic quinone-based compounds are frequently used for therapeutic purposes such as antitumor and anti-infection agents. (2) [...]

Sulfinyltoluquinones (2a-2c) were submitted to thermal or catalyzed [4+2] cycloaddition reactions with cyclopentadiene. For p-tolylsulfmyltoluquinones (2b) and (2c), almost complete C2-C3-chemo- and unlike-diastereoselectivity was achieved by catalysis with ZnBr2, yielding adducts 6. Under thermal conditions, Diels-Alder reaction took place at the C5-C6 double bonds of quinones 2a-2c, generating mixtures of diastereoisomeric like- and unlike-adducts 4. Key words: Diels-Alder reaction, sulfinyltoluquinones, sulfinyl group, stereochemical control, Ti-facial selectivity. On a soumis les sulfinyltoluquinones (2a-2c) a des reactions de cycloaddition thermiques ou catalysees avec le cyclopentadiene. Avec le ZnBr2 comme catalyseur, les p-tolylsulfmyltoluquinones (2b) et (2c) conduisent a 1a formation des adduits 6 et al diastereoselectivite chimique et dissemblable au niveau de 1a liaison C2-C3 est pratiquement complete. Dans des conditions thermiques, 1a reaction de Diels-Alder se produit au niveau des doubles liaisons C5-C6 des quinones 2a-2c qui conduit a 1a formation d'adduits 4 sous 1a forme de melanges diastereomeres semblables et dissemblables. Mots-cles : reaction de Diels-Alder, sulfinyltoluquinones, groupe sulfinyle, controle stereochimique, selectivite de 1a face n. [Traduit par 1a Redaction], Introduction The Diels-Alder (DA) reaction remains as one of the most powerful methods for the construction of cyclic systems with potential for stereochemical control of up to four stereogenic centers [...]