The intramolecular catalytic aldol cyclodehydration of meso-3,4-disubstituted 1,6-dialdehydes was investigated and it was found that the transformation is strongly dependent on the substrate structure. If the substituents are of carbonyl or acetonil protected diol type, the cyclopentene carbaldehydes are formed, while starting from acylated diols, an open chain unsaturated dialdehyde is generated. It was observed that the catalyst efficiency also depends on the substrate substituents and if the latter are of carbonyl or acyl protected diol type, both dibenzylammonium trifluoroacetate (Bn(2)NH(.)TFA) and piperidine-AcOH are effective, while only the second one catalyses the transformation of acetonil protected diols. It was shown that a secondary amine catalyses the reaction itself even in the cases where the corresponding salt is not effective. (c) 2005 Elsevier B.V. All rights reserved.