- Short and efficient total synthesis of fraxinellone limonoids using the stereoselective Oshima-Utimoto reaction
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(Chemical Equation Presented) The catalytic diastereoselective Oshima-Utimoto reaction was employed for the construction of fraxinellone and related members of this limonoid family of natural products. After formation of the five-membered lactone, a stereoselective aldol reaction and olefin metathesis established the bicyclic ring system in the natural products.
- Trudeau, Stephane,Morken, James P.
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- Synthesis and insecticidal activity of some novel fraxinellone-based esters
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In continuation of a program aimed at the discovery and development of natural products-based insecticidal agents, two series of novel fraxinellone-based esters were synthesized by modification at the C-4 or C-10 position of fraxinellone and evaluated for their insecticidal activity against the pre-third-instar larvae of Mythimna separata in vivo. An efficient method for the stereoselective synthesis of 4α-hydroxyfraxinellone from fraxinellonone was developed, and the steric configuration of 6h was unambiguously confirmed by X-ray crystallography. Among 37 compounds, some derivatives displayed potent insecticidal activity; especially compounds 6h, 6q, 6t, and 7q showed more promising insecticidal activity than toosendanin, a commercial botanical insecticide derived from Melia azedarach. This suggested that introduction of the fluorine atom on the phenyl ring could lead to a more potent compound than one possessing chlorine or bromine. Meanwhile, introduction of the heterocyclic fragments at the C-4 or C-10 position of fraxinellone was essential for their insecticidal activity. This will pave the way for further design, structural modification, and development of fraxinellone as an insecticidal agent.
- Guo, Yong,Yan, Yuanyuan,Yu, Xiang,Wang, Yi,Zhi, Xiao-Yan,Hu, Ying,Xu, Hui
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experimental part
p. 7016 - 7021
(2012/09/05)
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