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 Aryl Ketones with Aryl Aldehydes Catalyzed by Chiral BINOL-Derived Zincate Catalyst
作者:Hong Li、Chao-Shan Da、Yu-Hua Xiao、Xiao Li、Ya-Ning Su
DOI:10.1021/jo801182n
日期:2008.9.19
Directasymmetricaldol reaction of aryl ketones with aryl aldehydes catalyzed by chiral metal complex is reported for the first time herein. Two novel semicrown chiral ligands 1a and 1b were synthesized from (S)- and (R)-BINOL, respectively, and then employed to catalyze the directasymmetricaldol addition of aryl ketones to aryl aldehydes. Introduced with 2.0 equiv of diethylzinc, 1b had higher
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
Investigations of enantioreversal in both direct and directed enantioselective aldol reactions catalyzed by CuCl2[(−)-sparteine] and NiCl2[(−)-sparteine] complexes
作者:H. Maheswaran、P.J. Amal Joseph、K. Leon Prasanth、S. Priyadarshini、P. Satyanarayana、Praveen R. Likhar、M. Lakshmi Kantam
DOI:10.1016/j.tetasy.2010.07.008
日期:2010.9
chiral [CuCl2(sparteine)] 1 and [NiCl2(sparteine)] 2 complexes as catalysts under fluoride anion-promoted double catalytic activation (DCA) conditions cause enantioreversal in the asymmetric Mukaiyama aldol reaction of 1-phenyl-1-trimethylsiloxyethylene with various aromatic aldehydes. A similar enantioreversal also occurs in the direct aldol reaction between methyl vinyl ketone and various aromatic aldehydes