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Amino-Claisen rearrangements and Diels-Alder reactions of ketene N,O-acetals: Reactivity studies. On the way to a novel tandem process?
Auteur(s)
Date de parution
2000-1-12
In
Helvetica Chimica Acta
Vol.
10
No
83
De la page
2712
A la page
2737
Mots-clés
Résumé
We report the synthesis of N-benzyl-N-[(E)-buta-1,3-dienyl]propanamide (6) and its corresponding O-silyl-subitituted ketene N,O-acetal 7 and their Diels-Alder reaction. Propanamide G reacted smoothly, whereas the yield obtained from 7 was low, probably due to polymerization of the dienophile induced by electron transfer. The ketene N,O-acetals 27a-g were synthesized starting from the corresponding benzamides 25a-e (Scheme 9). The ketene N,O-acetals 27a-g showed increased stabilities and underwent amino-Claisen rearrangements under thermal conditions. Using catalysts, interesting side reactions leading either to the annulated systems, rac-35-37 or to a beta -lactam rac-34 were observed.
Identifiants
Type de publication
journal article
