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Communication | Regular issue | Vol 60, No. 4, 2003, pp.785-790
Published online, 3rd March, 2003
DOI: 10.3987/COM-03-9711
π-Facial Selectivity in Diels-Alder Reactions of Cross-conjugated Ketones Bearing an Oxa-spiro-ring with Sterically Undemanding Dienes

Ryukichi Takagi, Wataru Miyanaga, Yukiko Tamura, Satoshi Kojima, and Katsuo Ohkata*

*Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan

Abstract

The Diels-Alder reactions of cross-conjugated ketones bearing an oxa-spiro-ring with some simple sterically undemanding dienes (cyclopentadiene, 2,3-cyclohexadiene, 2,3-dimethyl-1,3-butadiene) afforded the adduct with high π-facial selectivity under mild conditions. The π-facial selectivity can be explained in terms of Cieplak model.