Novel Use of N-Benzoyl-N,O-acetals as N-Acylimine Equivalents in Asymmetric Heterocycloaddition: An Extended Enantioselective Pathway to β-Benzamido Aldehydes
摘要:
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 SnCl4-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.
An Improved Dienophile-Induced Access to Enantiopure 2,4-Dideoxysugar Lactones via Hetero Diels-Alder Reaction: Synthesis of the (+)-Lactone Moiety of Compactin
An Improved Dienophile-Induced Access to Enantiopure 2,4-Dideoxysugar Lactones via Hetero Diels-Alder Reaction: Synthesis of the (+)-Lactone Moiety of Compactin
作者:Gilles Dujardin、Sandrine Rossignol、Eric Brown
DOI:10.1055/s-1998-4489
日期:1998.5
Novel Use of <i>N</i>-Benzoyl-<i>N,O</i>-acetals as <i>N</i>-Acylimine Equivalents in Asymmetric Heterocycloaddition: An Extended Enantioselective Pathway to β-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 SnCl4-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.