Chiral separation of drug enantiomers by capillary electrophoresis using succinyl-β-cyclodextrin
A capillary electrophoretic method for the enantiomeric separation of 11 drugs was developed using an uncoated fused-silica capillary and succinyl β-cyclodextrin as a chiral additive. The effect of the pH of the background electrolyte on selectivity and resolution was studied in the range pH 3.3-9.3. Best results were obtained in a neutral medium. Generally, the presence of a hydroxy group at the chiral C-atom of the analyte seems to be essential because similar compounds without a hydroxy group at the chiral centre did not show chiral resolution. In addition to the enantioselective inclusion into the chiral cavity, hydrogen bondings and formation of ion pairs between the negatively charged selector and cationic analytes can be assumed as mechanisms.
Schmid,Wirnsberger,Guebitz
p. 852 - 854
(2007/10/03)
Stereodivergent synthesis of optically active tertiary alcohols via addition reaction of chiral 2-acyl oxazolidine with organometallics
It was observed that diastereoselectivity in an addition reaction to chiral 2-acyl oxazolidine, derived from (S)-prolinol, can be fully regulated under appropriate conditions. Addition of organotitanium triisopropoxides provided (S)-tertiary alcohols, while organolithium reagents afforded the corresponding (R)-alcohols. Application of this methodology was demonstrated in the synthesis of (+)- and (-)-trihexyphenidyl.