Novel use of N-benzoyl-N,O-acetals as N-acylimine equivalents in asymmetric heterocycloaddition: an extended enantioselective pathway to beta-benzamido aldehydes.
For the first time, easily available N-(alpha-methoxyalkyl)amides were successfully used as synthetic equivalents of N-acylimines in an asymmetric heterocycloaddition process. The facial-controlled formation of 6-alkoxydihydrooxazines was thus achieved by SnCl(4)-promoted heterocycloaddition of (R)-O-vinyl pantolactone. By simple acidic hydrolysis of the crude heteroadducts, new beta-aryl- and beta-alkyl-substituted benzamido aldehydes were thus obtained in good overall yields with high enantioselectivities.
Gizecki
Patricia
P
Laboratoire de Synthèse Organique UMR CNRS 6011, Université du Maine, F-72085 Le Mans Cedex 9, France.
Dhal
Robert
R
Poulard
Céline
C
Gosselin
Pascal
P
Dujardin
Gilles
G