Analytical Sciences

Crystal Structure of Methyl endo-8-Cyano-exo-8-methyl-3-oxo-2-oxabicyclo[2.2.2]oct-5-ene-6-carboxylate

Tetsuro SHIMO,*  Mikio YASUTAKE,** Teruo SHINMYOZU,** and Kenichi SOMEKAWA*

*Department of Applied Chemistry and Chemical Engineering, Kagoshima University, Korimoto, Kagoshima 890-0065, Japan
**Institute for Fundamental Research of Organic Chemistry (IFOC), Kyushu University, Hakozaki, Fukuoka 812-8581, Japan

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.

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