Kinetic Resolution of β-Hydroxy Carbonyl Compounds via Enantioselective Dehydration Using a Cation-Binding Catalyst: Facile Access to Enantiopure Chiral Aldols
作者:Sushovan Paladhi、In-Soo Hwang、Eun Jeong Yoo、Do Hyun Ryu、Choong Eui Song
DOI:10.1021/acs.orglett.8b00547
日期:2018.4.6
β-hydroxy carbonyl (aldol) compounds through enantioselective dehydration process was developed using a cation-binding Song’s oligoethylene glycol (oligoEG) catalyst with potassium fluoride (KF) as base. A wide range of racemic aldols was resolved with extremely high selectivity factors (s = up to 2393) under mild reaction conditions. This protocol is easily scalable. It provides an alternative approach for
Direct asymmetric aldol reaction of acetophenones with aromatic aldehydes catalyzed by chiral Al/Zn heterobimetallic compounds
作者:Xiao Li、Lei Zhang、Yu-Hua Xiao、Qi-Peng Guo、Chao-Shan Da、Hong Li、Xiaoju Liu、Xiangrong Ma、Yajun Ma
DOI:10.1134/s1070363216080247
日期:2016.8
Chiral Al/Zn heterobimetallic complexes are effective catalysts for the direct highly enantioselective aldol reaction of acetophenones with aromatic aldehydes. The Al site in the complex acts as a Lewis acid to activate aldehyde, whereas ethylzinc alkoxide plays a role of a Brønsted base to form a reactive zinc enolate with acetophenone. Distinct nature of two different metals contributes to the efficient
<i>N</i>-Triflylthiophosphoramide Catalyzed Enantioselective Mukaiyama Aldol Reaction of Aldehydes with Silyl Enol Ethers of Ketones
作者:Cheol Hong Cheon、Hisashi Yamamoto
DOI:10.1021/ol100233t
日期:2010.6.4
The first Brønsted acid catalyzed asymmetric Mukaiyama aldol reaction of aldehydes using silylenolethers of ketones as nucleophiles has been reported. A variety of aldehydes and silylenolethers of ketones afforded the aldol products in excellent yields and good to excellent enantioselectivities. Mechanistic studies revealed that the actual catalyst may be changed from the silylated Brønsted acid
Chiral Bipyridine Ligand with Flexible Molecular Recognition Site: Development and Application to Copper‐Catalyzed Asymmetric Borylation of α,β‐Unsaturated Ketones
Asymmetric Catalysis: A novel chiral bipyridine ligand with a flexible hydrogen-bond donor was developed based on the TS-stabilization concept. This designed chiral bipyridine ligand was applied to the copper-catalyzed asymmetric borylation of a wide range of α,β-unsaturated ketones, affording the borylated products in high yields with high enantioselectivities. The potential of a high-level control