Patent ID: 6114548
Filing Date: 2000-09-05
Classification: C07D

Abstract:
A process for the preparation of 5,6-dihydropyrans of the general formula: ##STR2## in which R is a C1-C10 aliphatic group or phenyl group which is unsubstituted or substituted with one or more C1-C5 alkyl groups or one other functional group and in which R.sub.1 -R.sub.4 are H or C1-C5 alkyl groups, comprising reacting the corresponding aldehyde RCHO with the corresponding diene R.sub.1 CH.dbd.CR.sub.2 --CR.sub.3 .dbd.CHR.sub.4 in the presence of a catalyst comprising a perfluorinated organic sulphonic acid or a Bronsted acid derivative thereof.