No abstract

Durch Umsctzung von Pentanal mit Crotonsaure-ethylester wird 3-Mcthyl-4-oxooctansaure-ethylester (2) gebildet, der sich mit NaBH4 reduzieren und in saurer Losung zu racemischem cis/trans-3-Mcthyl-4-octanolid 1 cyclisieren la&. Das Synthesegemisch wird chromatographisch leicht in cis-( l a la') und trans-Isomere ( l b * lb') getrennt. Aus l a - 1110, 1065, 1020, 995, 970, 965, 935, 905, 800, 785, 745, 645 cm-'. -

Enantioselective gas chromatography a-Cyclodextrin Lactones Diols 0-Al kylgl ycerols Chiral pharmaceuticals SummaryThe properties of hexa kis(3-0-acetyl-2,6-di-O-pentyl)-a-cyclodextrin as a chiral stationary phase for capillary gas chromatography are described. For the first time the enantiomers of a series of different lactones are separated and their order of elution is assigned. Moreover, the enantiomers of trifluoroacetylated aldols and amino alcohols, the cyclic carbonates of 1,2-diols, 1 ,3-diols, 0-alkylated glycerols, and some chiral pharmaceuticalsarealso separated on the new chiral phase. The modified a-cyclodextrin is stable above 20OoC.

SummaryThe stereodifferentiation of chiral secondary alcohols, 4(5)-alkyl-substituted y (b)-lactonesvia corresponding 1,4(1,5)-diols, chiral l,bdiols, and 1-thioalkan-3-01s was carried out by diastereomeric derivatiration with (S)-0-acetyllactyl chloride as a chiral auxiliary. This procedure is a convenient and reliable method for screening the enantiomeric composition of these naturally occurring flavor volatiles.

In stitu t für P harm azie und L ebensm ittelchem ie d e r U niversität W ürzburg, A m H u b lan d , D-8700 W ürzburg, B u ndesrepublik D eutschland Z . N aturforsch. 42c, 1 159 -1 1 6 4 (1987); received Ju n e 22, 1987 O xocarboxylic A cids. Y east A sym m etrie reduction of 4(5)-oxocarboxylic acids (esters) by b a k e r's yeast and cyclization in acidic m edia yields optically active y(6)-lactones. T he evaluation of th eir chirality and optical pu rity was carried out by H P L C (H R G C ) analysis o f the c o rresp o n d in g l,4 (1 .5 )-d io ls via diastereo m eric esters with (/?)-M osher acid (M T P A ) and (S)-O -acyllactic acids respectively. By in creasing the 4(5) alkyl side chain 4 R (5 R ) co nfigurated y (6 )-lacto n es w ith high ee-values are g e n era te d . EinleitungHPLC (präp.): LEW A Pumpe (max. Fördermen-