Fused silica capillary columns coated with several alkyl or acyl cyclodextrin derivatives, especially those of a-and 0-cyclodextrins, are suitable for the enantiomer separation of a wide variety of volatile compounds of different molecular size and functionality. Positional isomers and more than 250 pairs of optical isomers have been resolved, including chiral hydrocarbons, acetals, ethers, epoxides, carbonates, lactones, esters, acids, ketones, aldehydes, alcohols, halocarbons, and also nitrogenand sulfur-containing compounds.The physical properties of the cyclodextrin derivatives, even those obtained as viscous fluids, could be improved by dissolving them in polysiloxane liquid phases commonly used for GLC. Experimental2.

Zusammenfassung: Die Reaktionsgeschwindigund die dabei auftretende Racemisierung unterkeiten der Aminolyse der Benzyl-, Phenyl-,psucht. Es zeigte sich, daß der RacemisierungsNitrophenyl-und Pentachlorphenylester des Ben-schütz der Benzyloxycarbonyl-Schutzgruppe zyloxycarbonylphenylalanins wurden bei verauch bei Anwendung höherer Temperaturen wäh-schiedenen Temperaturen bis zu 90 °C bestimmt rend der Peptidsynthese erhalten bleibt. Aminolysis and Racemization of Activated Esters with the Use of High TemperaturesSummary: The reactivities in aminolysis of the investigated. It turned out that the protective benzyl, phenyl, p-nitrophenyl and pentachlorofunction of the benzyloxycarbonyl group in relaphenyl esters of benzyloxycarbonylphenylalation to the racemization was conserved, even at nine were ascertained at different temperatures the high temperatures used in the peptide synup to 90 °C and the occurrence of racemization thesis.

Abstract2,5‐Dimethyl‐2,4‐hexadiene (1) dimerizes under Lewis acid catalysis or in the presence of tris(4‐bromophenyl)aminium hexachlorostibanate (4) mainly to give exo‐3‐isopropenyl‐exo‐6‐isopropyl‐1,endo‐2,4,4‐tetramethylbicyclo[3.1.0]hexane (2). Small amounts of the acyclic dimer 2,5,7,7,10‐pentamethyl‐2,4,8‐undecatriene (3) and traces of other unidentified dimeric and trimeric products are formed as well. The latter are the only products in the presence of Brønsted acids, whereas 2 and 3 were not detected under these conditions. The structural assignment of 2 has been carried out by means of 2D‐INADEQUATE, ‐HETCOR, and ‐COSY spectra.

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