Organocatalytic enantioselective transient enolate protonation in conjugate addition of thioacetic acid to α-substituted N-acryloyloxazolidinones
作者:Rajshekhar A. Unhale、Nirmal K. Rana、Vinod K. Singh
DOI:10.1016/j.tetlet.2013.01.004
日期:2013.4
Organocatalytic conjugate addition of thioacetic acid to a series of α-substituted N-acryloyloxazolidin-2-ones followed by enantioselectiveprotonation has been studied in the presence of thiourea catalysts derived from cinchona alkaloids. Conjugate addition/protonation adducts have been obtained up to 97% ee and high yields. The methodology could serve as an easy and practical route to the syntheses
The asymmetric conjugateaddition of arylboronic acids to N-phthalimidodehydroalanine 1i catalyzed by Rh(I)/L1a enables the facile preparation of chiral functionalized phenylalanines. The reaction proceeds by a conjugateaddition and enantioselective protonation cascade, affording a rhodium enolate that undergoes re-face protonation. The reaction tolerates various arylboronic acids and can be used
Chiral diene-promoted room temperature conjugate arylation: highly enantioselective synthesis of substituted chiral phenylalanine derivatives and α,α-di(arylmethyl)acetates
作者:Jian-Ping Chen、Ming-Hua Xu
DOI:10.1039/d0ob00616e
日期:——
highly enantiocontrolled room temperature rhodium-catalyzed conjugate arylation process was developed. The reaction proceeds through 1,4-addition of α-substitutedacrylates followed by enantioselectiveprotonation using a C1-symmetric chiral bicyclo[2,2,2] diene as the ligand and water as the proton source. This exceptionally simple protocol provides a reliable and practical access to structurally important
Cu-Catalyzed Enantioselective Hydrogermylation: Asymmetric Synthesis of Unnatural β-Germyl α-Amino Acids
作者:Weidong Lin、Lijun You、Wei Yuan、Chuan He
DOI:10.1021/acscatal.2c04571
日期:2022.12.2
A copper-catalyzed asymmetricsynthesis of unnatural β-germyl α-amino acids is developed. This process undergoes an intermolecular enantioselective hydrogermylation of dehydroalanines with dihydrogermanes and trihydrogermanes, giving access to a variety of chiral β-germyl α-amino acid derivatives in decent yields with good to excellent enantioselectivities. Mechanistic studies indicate that a [Cu–Ge]
Application of a New Chiral Phosphepine to the Catalytic Asymmetric Synthesis of Highly Functionalized Cyclopentenes That Bear an Array of Heteroatom-Substituted Quaternary Stereocenters
作者:Yuji Fujiwara、Gregory C. Fu
DOI:10.1021/ja2049012
日期:2011.8.10
the design and synthesis of a new chiral phosphepine, the first catalytic asymmetric method for the [3 + 2] cycloaddition of allenes with olefins has been developed that generates cyclopentenes that bear nitrogen-, phosphorus-, oxygen-, and sulfur-substituted quaternary stereocenters. A wide array of racemic γ-substitutedallenes can be employed in this stereoconvergent process, which occurs with good