Asymmetric Catalytic Cycloetherification Mediated by Bifunctional Organocatalysts
摘要:
Oxacyclic structures such as tetrahydrofuran (THF) rings are commonly found in many bioactive compounds, and this has led to several efforts toward their stereoselective syntheses. However, the process of catalytic asymmetric cycloetherification for their straightforward synthesis has remained a challenge. In this study, we demonstrate a novel asymmetric synthesis method for THF via the catalytic cycloetherification of epsilon-hydroxy-alpha,beta-unsaturated ketones mediated by cinchona-alkaloid-thiourea-based bifunctional organocatalysts. This catalytic process represents a highly practical cycloetherification method that provides excellent enantioselectivities, even with low catalyst loadings at ambient temperature.
Asymmetric Catalytic Cycloetherification Mediated by Bifunctional Organocatalysts
作者:Keisuke Asano、Seijiro Matsubara
DOI:10.1021/ja207322d
日期:2011.10.26
Oxacyclic structures such as tetrahydrofuran (THF) rings are commonly found in many bioactive compounds, and this has led to several efforts toward their stereoselective syntheses. However, the process of catalytic asymmetric cycloetherification for their straightforward synthesis has remained a challenge. In this study, we demonstrate a novel asymmetric synthesis method for THF via the catalytic cycloetherification of epsilon-hydroxy-alpha,beta-unsaturated ketones mediated by cinchona-alkaloid-thiourea-based bifunctional organocatalysts. This catalytic process represents a highly practical cycloetherification method that provides excellent enantioselectivities, even with low catalyst loadings at ambient temperature.
Asymmetric Cycloetherification by Bifunctional Organocatalyst
作者:Keisuke Asano、Seijiro Matsubara
DOI:10.1055/s-0036-1591592
日期:2018.11
synthesis could be effectively performed via kinetic resolution using ζ-hydroxyenone containing a secondary alcohol moiety using a chiral phosphoric acid catalyst. Attempts to obtain enantiomerically enriched tetrahydrofuran derivatives via an intramolecular oxy-Michael addition reaction of ε-hydroxyenone is discussed. Despite previous difficulties associated with the asymmetric induction of this reaction