SummaryThe enantiomers of phenoxypropionic acid type herbicides have been resolved by capillary gas chromatography employing modified cyclodextrins as chiral stationary phases. Excellent separations were obtained with columns containing a 1 :I mixture of per-0-pentylated and per-0-methylated 6-cyclodextrin.pesticides and herbicides may differ by orders of magnitude, but little is known about their selective action. It has been found that the activity of the D( +) forms of some chiralphenoxypropionic acid derivatives (1-3; Figure 1) which are used as herbicides is about twice as high as that of the racemates.The enantiomers of the methyl esters of mecoprop and dichlorprop were also resolved on octakis(3-O-butyryl-2,6-di-O-penty1)y-cyclodextrin. On this phase the order of elution of the enantiomers was temperature-dependent, the elution order being reversed as the temperature passed through the isoenantioselective temperature. This is the first time such behavior has been observed with cyclodextrin derivatives.The enantiomers of the polychlorinated polycyclic pesticides cis-and trans-chlordane, oxychlordane, heptachlor, heptachlorepoxide, and three chiral organophosphorus pesticides could be resolved using selectively derivatiied cyclodextrin derivatives.

SummaryTransferring the site of specific substitution of dipentylated cyclodextrins with methyl or acyl residues from the secondary 3-hydroxyl group to the primary 6-hydroxyl group was expected to provide new information on the mechanism of chiral recognition-The 3-position points towards and the 6-position points away from the cyclodextrin cavity which via inclusion complex formation is supposed to play a major role in chiral separation.The "inverse" 6-0-acyl-2,3-di-0-pentyl-cyclodextrins displayed almost no enantioselectivity but the corresponding 6-0-methyl derivatives are a versatile supplement to the chiral capillary GC phases nowadays available. Among the compounds that could be enantiomerically resolved are alcohols, amino acids, alkyl halides, bicyclic ethers, acetals, olefins, other hydrocarbons and chiral pharmaceuticals.

SummaryNew p-and y-cyclodextrin derivatives, selectively substituted with n-pentyl and methyl groups, e.g. heptakis(2,6-di-Omethyl-3-O-pentyl)-~-cyclodextrin, octakis(2-O-methyl-3,6-di-0-penty1)-y-cyclodextrin, and octakis(2,6-di-O-methyl-3-0-penty1)-y-cyclodextrin, have been prepared from specifically protected intermediates.The new cyclodextrin derivatives exhibit unique enantioselectivity towards important chiral constituents of essential oils. The enantiomers of lavandulol, abisabolol, nerolidol, and other terpenoid alcohols could be resolved and their presence in different essential oils could be proved. Methyl jasmonate and epi-methyl jasmonate could, in addition, be detected in jasmine concrete by two-dimensional gas chromatography. The enantiomers of the macrocyclic ketone muscone have been separated for the first time.

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