DETERMINATION OF THE ROTATIONAL ENERGY BARRIER OF PLANAR-CHIRAL CYCLOPHANES USING DYNAMIC ENANTIOSELECTIVE GAS-CHROMATOGRAPHY AND COMPUTER-SIMULATION

Citation
Dh. Hochmuth et Wa. Konig, DETERMINATION OF THE ROTATIONAL ENERGY BARRIER OF PLANAR-CHIRAL CYCLOPHANES USING DYNAMIC ENANTIOSELECTIVE GAS-CHROMATOGRAPHY AND COMPUTER-SIMULATION, Liebigs Annalen, (6), 1996, pp. 947-951
Citations number
22
Categorie Soggetti
Chemistry
Journal title
ISSN journal
09473440
Issue
6
Year of publication
1996
Pages
947 - 951
Database
ISI
SICI code
0947-3440(1996):6<947:DOTREB>2.0.ZU;2-R
Abstract
We synthesized numerous new monosubstituted dioxa[11]paracyclophanes, which are planar-chiral atropisomers due to the hindered rotation of t he bridge about the aromatic plane, and we were able to resolve the en antiomers of these compounds by enantioselective gas chromatography wi th selectively modified cyclodextrims as chiral stationary phases in p olysiloxane solution. As a consequence of the competition between enan tiomeric resolution and enantiomerization (interconversion) during the gas chromatographic process, coalescence phenomena or formation of pl ateaus between peaks of both enantiomers are observable. The combinati on of these dynamic gas chromatographic investigations with computer s imulation of elution profiles allows the facile and precise determinat ion of the energy barrier of the enantiomerization reaction and the el ucidation of the influence of substituents on the energy barrier.