Based on a previously developed approach to the theory of unimolecular reac
tions of structural isomerization, the most probable mechanism of the conve
rsion of nonbranched (linear) isomeric forms of unsaturated hydrocarbons to
branched structures was proposed. It was demonstrated for the C8H10 compou
nd, as an example, that such a rearrangement should proceed through an inte
rmediate stage of formation of a ring followed by its opening.