Asymmetric Hydrogenation of Ketones and Enones with Chiral Lewis Base Derived Frustrated Lewis Pairs
作者:Bochao Gao、Xiangqing Feng、Wei Meng、Haifeng Du
DOI:10.1002/anie.201914568
日期:2020.3.9
The concept of frustratedLewispairs (FLPs) has been widely applied in various research areas, and metal-free hydrogenation undoubtedly belongs to the most significant and successful ones. In the past decade, great efforts have been devoted to the synthesis of chiral boron Lewis acids. In a sharp contrast, chiral Lewisbase derived FLPs have rarely been disclosed for the asymmetric hydrogenation.
Arene CHO Hydrogen Bonding: A Stereocontrolling Tool in Palladium-Catalyzed Arylation and Vinylation of Ketones
作者:Zhiyan Huang、Li Hui Lim、Zuliang Chen、Yongxin Li、Feng Zhou、Haibin Su、Jianrong Steve Zhou
DOI:10.1002/anie.201300621
日期:2013.4.26
Weak is powerful: For the arylation of tin enolates, the palladium catalyst engages in weak CHOhydrogen bonds to control stereoselectivity (see scheme). Similar catalysts capable of NHOhydrogenbonding also works well.
A novelcatalyticsystem based on copper(I) and chiral bis(phosphine) dioxides is described. This allows the arylation of silyl enol ethers to access enolizable α-arylated ketones in good yields and enantiomeric excess up to 95%. Noncyclic ketones are amenable substrates with this method, which complements other approaches based on palladium catalysis. Optimization of the ligand structure is accomplished
An efficient RuPHOX−Ru catalyzed asymmetric cascade hydrogenation of 3-substitutedchromones has been achieved under mild reaction conditions, affording the corresponding chiral 3-substituted chromanols in high yields with excellent enantio- and diastereoselectivities. A dynamic kinetic resolution process occurs during the subsequent hydrogenation of the C=O double bond, which is responsible for the