Bifunctionalorganocatalysts bearing amino and urea functional groups in a chiral molecular skeleton were applied to the enantioselective synthesis of axially chiral benzamides via aromatic electrophilic bromination. The results demonstrate the versatility of bifunctionalorganocatalysts for the enantioselective construction of axially chiral compounds. Moderate to good enantioselectivities were afforded
Enantioselective Synthesis of Tertiary α-Hydroxy Phosphonates Catalyzed by Carbohydrate/Cinchona Alkaloid Thiourea Organocatalysts
作者:Shasha Kong、Weidong Fan、Guiping Wu、Zhiwei Miao
DOI:10.1002/anie.201204287
日期:2012.8.27
A pinch of sugar: The new bifunctional carbohydrate/cinchonine‐based thiourea 1 has been designed for the asymmetric addition reaction of α‐ketophosphonates and trimethylsilyl cyanide, the product of which can be hydrolyzed to afford tertiary α‐hydroxy phosphonates with excellent enantioselectivities.
Bifunctional chiral thioureas have been successfully used as organocatalysts in enantioselectivefluorinations of β-ketoesters. The corresponding products could be obtained with good to excellent enantioselectivity in high yields by using N-fluorobisbenzenesulphonimide (NFSI) as fluorination reagent.
Immobilization of Functionalized epi-Cinchonine Organocatalysts on Controlled Porous Glass Beads: Applications in Batch and Continuous Flow
作者:Anthony J. Burke、Ana C. Amorim、Daniela P. Fonseca、Elisabete P. Carreiro、Gesine J. Hermann、Hans-Jürgen Federsel
DOI:10.1055/a-1916-4858
日期:2022.10
squaramide-cinchonine organocatalyst was immobilized in a controlled way onto three types of commercial porous glass beads EziG™ (EziG OPAL, EziG Amber, and EziG Coral) and applied in asymmetric Michael reactions. The performance of the immobilized catalysts was evaluated under batch and continuous-flow conditions, showing promising results in both approaches. In batchreactions, 0.8 and 1.6 mol% of
The stereoselective reaction of α-amido-substituted malonicacid half oxyesters (amido-MAHOs) with isatins was developed. A cinchona alkaloid thiourea catalyst gave products bearing a tetrasubstituted stereogenic centre in high yields with high diastereo- and enantioselectivities (75-99% yield, 83:17-97:3 dr, 92:8-99:1 er). The obtained products can be converted into some chiral compounds without loss