text: A wide variety of divinylcyclopropanes undergo the titular reaction. These precursors have been generated by a variety of methods, including the addition of cyclopropyl nucleophiles (salts of lithium, or copper) to activated double or triple bonds, elimination of bis(2-haloethyl)cyclopropanes and cyclopropanation.
  In the example below, cuprate addition-elimination generates the transient enone 1, which rearranges to spirocycle 2.
  Organolithiums can be employed in a similar role, but add in a direct fashion to carbonyls. Products with fused topology result.
  Rearrangement after elimination of ditosylates has been observed; the chlorinated cycloheptadiene thus produced isomerizes to conjugated heptadiene 3 during the reaction.
  Cyclopropanation with conjugated diazo compounds produces divinylcyclopropanes that then undergo rearrangement. When cyclic starting materials are used, bridged products result.
  Substrates containing three-membered heterocyclic rings can also undergo the reaction. cis-Divinylepoxides give oxepines at elevated temperatures (100 °C). trans Isomers undergo an interesting competitive rearrangement to dihydrofurans through the intermediacy of a carbonyl ylide and the same ylide intermediate has been proposed as the direct precursor to the oxepine product 4. Conjugated dienyl epoxides form similar products, lending support to the existence of an ylide intermediate.
  Divinyl aziridines undergo a similar suite of reactions providing azepines or vinyl pyrrolines depending on the relative configuration of the aziridine starting material. Divinyl thiiranes can provide thiepines or dihydrothiophenes, although these reactions are slower than those of the corresponding nitrogen- and oxygen-containing compounds.