Stereoisomeric flavour compounds XLV: Structure analysis of 2-alkoxy-5-alkyl-tetrahydrofurans

The synthesis of several 2-alkoxy-5-alkyl-tetrahydrofurans is of interest in our investigations of structure–function relationships of chiral flavour compounds. For the preparation of the enantiomeric acetals the unambiguous configurational assignment of the cis and trans series of these compounds is indispensable. By means of crystalline acetal derivatives the absolute structure of a model compound in the cis and the trans configuration is revealed by X-ray measurement and correlated with the corresponding cis and trans configurated aroma compounds. The first complete structure elucidation of the class of 2-alkoxy-5-alkyltetrahydrofurans has been carried out.