Dimers of α-alkylacroleins can be prepared by a Diels-Alder reaction [1, 2] and also as side products in the synthesis of α-alkylacroleins due to their thermal dimerization [3, 4]. Despite the widespread use of a diene synthesis for the preparation of various carbo- and heterocyclic compounds the α-alkylacrolein dimers belong to a class of rather poorly studied compounds – pyrans. Literature data regarding methods of synthesis, properties, and areas of use for the pyrans are ...