Acid-Catalyzed Reactions of Sarcophytoxide, a Marine Cembranoid

Perchloric acid treatment of sarcophytoxide, a marine cembranoid possessing an epoxide, brought about epoxide-ketone rearrangement affording ketones. When the reaction time was long (22 h), a minor ketone that was antipodal to the ketone obtained in a short-time (10 min) reaction was formed. These p...

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Published inBulletin of the Chemical Society of Japan Vol. 81; no. 5; p. 562
Main Authors Nii, Keiji, Tagami, Keiko, Kijima, Masaru, Munakata, Tatsuo, Ooi, Takashi, Kusumi, Takenori
Format Journal Article
LanguageEnglish
Published Tokyo Chemical Society of Japan 01.05.2008
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Summary:Perchloric acid treatment of sarcophytoxide, a marine cembranoid possessing an epoxide, brought about epoxide-ketone rearrangement affording ketones. When the reaction time was long (22 h), a minor ketone that was antipodal to the ketone obtained in a short-time (10 min) reaction was formed. These puzzling findings, considering that the starting epoxide had three asymmetric carbons, were interpreted by surveying the structures of other ketonic products. The stereochemistry of a major ketone, which had been wrongly assigned, was corrected by extensive analyses of NMR spectra. The correct stereochemistry indicated that the epoxide-ketone rearrangement took a course via a cationic intermediate.
ISSN:0009-2673
1348-0634