Thermal reactions of 8-methylbicyclo[4.2.0]oct-2-enes: competitive diradical-mediated [1,3] sigmatropic, stereomutation, and fragmentation processes. Academic Article uri icon


  • [reaction: see text] At 275 degrees C, 8-exo-methylbicyclo[4.2.0]oct-2-ene (1a) undergoes a [1,3] sigmatropic rearrangement to 5-methylbicyclo[2.2.2]oct-2-enes, of which the orbital symmetry-allowed si product is only marginally favored over the forbidden sr product; that is, si/sr is 2.4. Accompanying the [1,3] shift are significant amounts of epimerization and fragmentation. The 8-endo epimer 1b, which yields no [1,3] product, experiences primarily direct fragmentation and secondarily epimerization. A diradical intermediate can account for all such observations.

published proceedings

  • J Org Chem

author list (cited authors)

  • Bogle, X. S., Leber, P. A., McCullough, L. A., & Powers, D. C.

citation count

  • 16

complete list of authors

  • Bogle, Xavier S||Leber, Phyllis A||McCullough, Lynne A||Powers, David C

publication date

  • October 2005