Total Synthesis of (±)-Tetramethylmediterraneol B

Kiyomi Kakiuchi*, Ippei Nakamura, Fumiyuki Matsuo, Mono Nakata, Mikihiro Ogura, Tobe Yoshito, Hideo Kurosawa

*Corresponding author for this work

Research output: Contribution to journalArticle

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Abstract

A diterpenoid having the structure proposed for the tetramethylated derivative 2 of mediterraneol B (1) has been synthesized in a stereocontrolled manner via coupling between the hydroquinone side chain 7 and the bicyclo[4.2.1]nonane core 8 followed by buildup of the 1,3-diketone functionality. The hydroquinone segment 7 was prepared easily according to the reported method. Synthesis of the key component 8 was undertaken starting from tert-butylcyclohexenone 11. The cornerstone of the synthesis is the acid-catalyzed rearrangement of bicyclo[4.2.0]octanone 10 to the ketone 9 which has the bicyclononane skeleton and has clues for further manipulation. As a model study for introduction of the 1,3-diketone functionality, bicyclo[4.2.1]nonane-2,4-dione 43 was also prepared. Methylation of the penultimate intermediate 62 under conditions reported in isolation of the natural product did not give the tetramethyl ether 2 but a mixture of the trimethyl ethers 64 and 65. With Me3OBF4 and Proton Sponge, the transformation to 2 was successfully achieved. The structure of the synthetic 2 was secured by the X-ray crystallographic structure analysis of the key compound 60. However, the difference between the spectra of the synthetic 2 and those of the compound derived from the natural product suggests the structure of the latter is incorrect and requires revision.

Original languageEnglish
Pages (from-to)3318-3333
Number of pages16
JournalJournal of Organic Chemistry
Volume60
Issue number11
DOIs
StatePublished - 1 Jun 1995

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    Kakiuchi, K., Nakamura, I., Matsuo, F., Nakata, M., Ogura, M., Yoshito, T., & Kurosawa, H. (1995). Total Synthesis of (±)-Tetramethylmediterraneol B. Journal of Organic Chemistry, 60(11), 3318-3333. https://doi.org/10.1021/jo00116a014