99(P-32) Formal Synthesis of Optically Active Ingenol
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- Watanabe Kazushi
- Graduate School of Pure and Applied Sciences, University of Tsukuba
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- Suzuki Yuto
- Graduate School of Pure and Applied Sciences, University of Tsukuba
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- Aoki Kenta
- Graduate School of Pure and Applied Sciences, University of Tsukuba
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- Sakakura Akira
- Graduate School of Pure and Applied Sciences, University of Tsukuba
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- Suenaga Kiyotake
- Graduate School of Pure and Applied Sciences, University of Tsukuba
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- Kigoshi Hideo
- Graduate School of Pure and Applied Sciences, University of Tsukuba
Bibliographic Information
- Other Title
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- 99(P-32) 光学活性インゲノールの合成(ポスター発表の部)
Abstract
Ingenol is a diterpenoid isolated from Euphorbia ingens, possessing a bicyclo[4.4.1]undecane skeleton with a highly strained inside, outside-intrabridgehead stereochemistry. Several strategies for construction of the unique skeleton have been reported, however, direct cyclization to the inside, ousidet-bicyclo[4.4.1]undecane system has not been reported. Recently, two total syntheses in a racemic form using the aforementioned strategies were reported by Winkler and Tanino-Kuwajima. We would like to report the construction of strained carbon skeletons of ingenol by direct cyclization with ring-closing olefin metathesis (RCM). With well-designed diene compounds 4, 23, and 24, RCM was found to be applicable to the formation of a highly strained skeleton of ingenol, and formal total synthesis of optically active ingenol (1) was achieved. The key features of this synthesis are construction of an A-ring by spirocyclization of ketone 21 with an allylic chloride unit and ring closure of a B-ring by olefin metathesis. Starting from Funk's keto ester 17, the key intermediate aldehyde 27 in Winkler's total synthesis was synthesized in eight steps in 12.5% overall yield. This strategy of direct cyclization of a strained inside-outside skeleton provided the first easy access to optically active ingenol.
Journal
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- Symposium on the Chemistry of Natural Products, symposium papers
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Symposium on the Chemistry of Natural Products, symposium papers 46 (0), 569-574, 2004
Symposium on the Chemistry of Natural Products Steering Committee
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Details 詳細情報について
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- CRID
- 1390282681054979584
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- NII Article ID
- 110006682480
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- ISSN
- 24331856
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- Text Lang
- ja
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- Data Source
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- JaLC
- CiNii Articles
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- Abstract License Flag
- Disallowed