Organocatalytic Preparation of Simple β-Hydroxy and β-Amino Esters: Low Catalyst Loadings and Gram-Scale Synthesis
摘要:
A combined amino- and N-heterocyclic carbene (NHC)-catalyzed one-pot reaction sequence for the synthesis of simple enantioenriched beta-hydroxy and beta-amino esters using commercially available catalysts at low catalyst loadings has been developed. The desired products were obtained in high yield and excellent enantiopurity. The generation of quaternary stereocenters and application in gram-scale synthesis were also realized, with no requirements of inert or anhydrous reaction conditions, thus making this transformation a highly practical protocol.
Asymmetric Epoxidation of α,β-Unsaturated Aldehydes in Aqueous Media Catalyzed by Resin-Supported Peptide- Containing Unnatural Amino Acids
作者:Kengo Akagawa、Kazuaki Kudo
DOI:10.1002/adsc.201000805
日期:2011.4.18
The enantio‐ and diastereoselective epoxidation of α,β‐unsaturated aldehydes in aqueousmedia was realized using a resin‐supported peptide catalyst. Introducing the hydrophobic and bulky unnaturalaminoacid 3‐(1‐pyrenyl)alanine into the peptide sequence was effective for enhancing the reaction rate and enantioselectivity.
A combined amino- and N-heterocyclic carbene (NHC)-catalyzed one-pot reaction sequence for the synthesis of simple enantioenriched beta-hydroxy and beta-amino esters using commercially available catalysts at low catalyst loadings has been developed. The desired products were obtained in high yield and excellent enantiopurity. The generation of quaternary stereocenters and application in gram-scale synthesis were also realized, with no requirements of inert or anhydrous reaction conditions, thus making this transformation a highly practical protocol.