title: Crystal structure of methyl endo-8-cyano-exo-8-methyl-3-oxo-2-oxabicyclo[2.2.2]oct-5-ene-6-carboxylate.
abstract: A photochemical cycloaddition reaction of methyl 2-pyrone-5-carboxylate with methacrylonitrile mainly gave a [4 + 2] cycloadduct, assigned as methyl endo-8-cyano-exo-8-methyl-3-oxo-2-oxabicyclo[2.2.2]oct-5-ene-6-carboxylate, whose structure was determined by an X-ray diffraction study. The formation of the cycloadduct was reasonably explained by considering a biradical intermediate having a less steric hindrance between the methoxycarbonyl group and the cyano group.
authors.affiliation: Department of Applied Chemistry and Chemical Engineering, Kagoshima University, Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Shimo
authors.forename: Mikio
authors.initials: M
authors.lastname: Yasutake
authors.forename: Teruo
authors.initials: T
authors.lastname: Shinmyozu
authors.forename: Kenichi
authors.initials: K
authors.lastname: Somekawa