Actual applications of thermolysis reactions in organic synthesis are
described with emphasis on pericyclic reactions of small ring hydrocar
bons such as cyclopropanes (vinylcyclopropanes, 1,2-divinylcyclopropan
es), cyclobutanes, cyclobutenes, and benzocyclobutenes. Several exampl
es for the application of retro Diels-Alder reactions for the preparat
ion of reactive intermediates as well as for the synthesis of interest
ing target molecules are given.