Vinylcyclopropane rearrangement

The vinylcyclopropane rearrangement is a ring expansion reaction, converting a vinyl-substituted cyclopropane ring into a cyclopentene ring:

It is often classified as a sigmatropic rearrangement, though the special properties of the cyclopropane ring makes it atypical for this reaction class. Due to the high reactivity and partial pi character of this ring, the reaction often proceeds readily at lower temperatures. Vinylcyclopropane rearrangements may be effected thermally or photochemically. An analogous reaction converting a vinylcyclobutane to a cyclohexene ring has been observed under microwave irradiation. [ [http://www.organic-chemistry.org/Highlights/2004/15June.shtm Vinyl Cyclobutane Rearrangements] , June 15, 2004]

References

1. E M Mil'vitskaya, A V Tarakanova and Alfred F Plate. Thermal Rearrangements of Vinylcyclopropanes. Russ. Chem. Rev. 1976;45:469-478. doi|10.1070/RC1976v045n05ABEH002675.

2. Z. Goldschmidt and B. Crammer. Vinylcyclopropane rearrangements. Chem. Soc. Rev. 1988;17:229-267. doi|10.1039/CS9881700229.