Primary amine-metal Lewis acid bifunctional catalysts based on a simple bidentate ligand: direct asymmetric aldol reaction
作者:Philias Daka、Zhenghu Xu、Alexandru Alexa、Hong Wang
DOI:10.1039/c0cc00917b
日期:——
A novel class of primary amine-metal Lewis acid bifunctionalcatalysts based on a bidentate ligand was developed. These catalysts were highly efficient in catalyzing the direct asymmetricaldolreactions of ketones offering excellent stereoselectivity. The aldolreactions required a low catalyst loading (2.5 mol%), and were water compatible.
Asymmetric Inverse-Electron-Demand Hetero-Diels-Alder Reaction of Six-membered Cyclic Ketones: An Enamine/Metal Lewis Acid Bifunctional Approach
作者:Zhenghu Xu、Lu Liu、Kraig Wheeler、Hong Wang
DOI:10.1002/anie.201100160
日期:2011.4.4
On demand: The first example of the title reaction involving cyclic ketones and β,γ‐unsaturated α‐ketoesters has been achieved using the novel enamine/metal Lewisacid bifunctional catalysis (see scheme; Tf=trifluoromethanesulfonyl). Enones with both electron‐withdrawing and electron‐donating groups at the γ position reacted smoothly with cyclohexanone affording the products in excellent chemo‐ and
A Three-Component Reaction Based on a Remote-Group-Directed Dynamic Kinetic Aza-Michael Addition: Stereoselective Synthesis of Imidazolidin-4-ones
作者:Zhenghu Xu、Tyler Buechler、Kraig Wheeler、Hong Wang
DOI:10.1002/chem.200903508
日期:2010.3.8
with an aldehyde and a Michael acceptor to form stable imidazolidin‐4‐ones with high stereoselectivity. A dynamickinetic aza‐Michael addition was discovered and applied to the three‐component reaction to enforce high stereoselectivity. A remote group was incorporated to invert the reaction process and direct the reaction towards the desired product (see scheme).
Metal-induced supramolecular chirality inversion of small self-assembled molecules in solution
作者:Zoran Kokan、Berislav Perić、Mario Vazdar、Željko Marinić、Dražen Vikić-Topić、Ernest Meštrović、Srećko I. Kirin
DOI:10.1039/c6cc09203a
日期:——
Non-covalent self-assembled chiral alanyl aminopyridine ligand exhibits supramolecular chirality in solution, independent of the organic solvent used. The supramolecular chirality of the assemblies is completely inverted by complexation to zinc...