Résultat de la recherche
Preparation of N-alkylketene-N-butadienyl-N,O-silyl acetals
The synthesis of a series of dienamides 5a-j using Oppolzer's method is described. Using Rathke's method the ketene N,O-silyl acetals 6a-j can be obtained in good yield from the corresponding dienamides. The ketene acetals are obtained free of base and free of salts. They are stable and can be stored at - 20 degrees C. The new dienes are useful reagents for tandem reactions.
Preparation of N-Alkylketene-N-Butadienyl-N,O-Silyl Acetals
The synthesis of a series of dienamides 5a-j using Oppolzer’s method is described. Using Rathke’s method the ketene N,O-silyl acetals 6a-j can be obtained in good yield from the corresponding dienamines. The ketene acetals are obtained free of base and free of salts. They are stable and can be stored at -20°C. The new dienes are useful reagents for tandem reactions.
The preparation and the cascade reactions of N-butadienyl-N-alkylketene N,O-tert-butyldimethylsilyl acetals
The preparation of N-butadienyl-N-alkylketene N,O-tert-butyldimethylsilyl acetals (11a-d) from readily available starting materials is described. The cascade Diels-Alder reaction followed by acylation of these ketene acetals yields bicyclic and tricyclic products 7, 13a,b and 14c,d with high diastereoselectivity. Copyright (C) 1996 Elsevier Science Ltd