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).
Asymmetric Synthesis of Chromans Through Bifunctional Enamine‐Metal Lewis Acid Catalysis
作者:Jacqkis Davis、Mojgan Gharaee、Chamini V. Karunaratne、Jose Cortes Vazquez、Mikayla Haynes、Weiwei Luo、Vladimir N. Nesterov、Thomas Cundari、Hong Wang
DOI:10.1002/chem.202200224
日期:2022.5.11
A concise method for the asymmetric synthesis of tricyclic chromans from salicylaldehydes and cyclic ketones was developed through bifunctional enamine-metal Lewis acidcatalysis. Mechanism of the chroman formation reaction was proposed and investigated with deuterium experiments and DFT calculations. Tricyclic chromans containing three consecutive stereogenic centers were prepared in good yields (up