Molecular recognition of benzoin and bi-beta-naphthol analogues by Chirex 3001-based chiral stationary phase

The simplified model of (R)-phenylglycine based chiral stationary phase (Chirex 3001) was built to investigate the process of chiral recognition of benzoin and bi-beta-naphthol and their analogues by molecular mechanics methods. The results showed that the driving force of chiral recognition came from the pi-pi stacking, hydrogen bond and van der Waals interactions between the host and the guest molecule. The host preferred to bind with S-enantiomers of benzoin and its analogues 1 similar to 3, and preferred to bind with R-enantiomers of bi-beta-naphthol and its analogues 4 similar to 6. This was consistent with the HPLC experimental results. The separation factors were 1.02, 1.04 and 1.11 respectively for compounds 1 similar to 3 when n-hexane/1,2-dichloroethane/ethanol (V : V : V=83.5 : 15 : 1.5) was used as mobile phase, and the R-enantiomers were eluted first. The separation factors were 1.23, 1.26 and 1.11 respectively when n-hexane/chloroform/ethanol (V : V : V=78.5 : 20 : 1.5) was used as mobile phase, and the S-enantiomers were eluted first

Enantioseparation of binaphthol and its derivatives on cellulose tris(3,5-dimethylphenyl carbamate)

A Chiralcel OD-H column was used for the normal phase enantioseparation of binaphthol and its derivatives. Unexpectedly, binaphthol and its dibromo-substituted analogue could not be enantioseparated fully, whereas its ether and ester derivatives gave complete or partial resolution. Aspects of the chiral recognition are discussed further through calculated thermodynamic parameters

Vanadium-catalyzed enantioselective oxidation of allyl sulfides

The enantioselective oxidation of allyl sulfides with a vanadyl complex of 3,5-diiodosalicylidene tert-leucinol as a catalyst and aqueous hydrogen peroxide as an oxidant afforded chiral allylsulfoxides with high enantioselectivities of up to 97.3% ee and moderate yields. (C) 2011 Elsevier Ltd. All rights reserved.National Science Foundation of China[20672088, 20705031]; Ministry of Human Resources and Social Security of China; Science and Technology Bureau of Sichuan[2011HH0016]; Chengdu Science and Technology Bureau; Chengdu University of Technolog