Detlev H. Hochmuth

Synthesis, resolution and determination of energy barriers to rotation of atropisomeric, planar-chiral [n]paracyclophanes by dynamic enantioselective gas chromatography and computer simulation

Abstract We herein report on the synthesis of substituted carbocyclic [11]paracyclophanes, which are planar-chiral and atropisomeric. Their energy barrier to rotation was determined by dynamic enantioselective gas chromatography on selectively modified cyclodextrins as chiral stationary phases and subsequent computer simulation of the plateau-shaped elution profiles (DGC–CS). The energy barriers are compared with those of analogous dioxa[11]paracyclophanes.

Resolution of chiral [2.2]paracyclophanes by enantioselective gas chromatography

Abstract [2.2]Paracyclophanes possessing a substituent on the aromatic ring are dissymmetric compounds due to the restricted rotation of the benzene rings. For interconversion of enantiomers temperatures above 200 °C are necessary. We have succeeded in resolving the enantiomers of some mono-substituted [2.2]paracyclophanes by enantioselective gas chromatography using 2,3-di-O-methylated β-cyclodextrins with bulky O-(1,1,2-trimethylpropyl)-dimethylsilyl or O- t .butyl-dimethylsilyl substituents in the 6-position of the glucose units as chiral stationary phases.

Gas chromatographic enantioseparation of allenes

Abstract Enantioselective gas chromatography with modified cyclodextrins as stationary phases is successfully used to separate chiral allenic hydrocarbons - including kinetically labile 1,2-cyclooctadiene - and 1-halo-1,2-butadienes.