- Ruthenium-catalyzed asymmetric N -demethylative rearrangement of isoxazolidines and its application in the asymmetric total syntheses of (-)-(1 r,3 s)-hpa-12 and (+)-(1 s,3 r)-hpa-12
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An asymmetric N-demethylative rearrangement of 1,2-isoxazolidines catalyzed by ruthenium is described. Enantioenriched syn-1,3-aminoalcohols as well as cis-1,3-oxazinanes, which are useful building blocks, can be efficiently prepared stereospecifically by this reaction in good yields, via the isoxazolidine intermediates in situ generated from a nitrone bearing a chiral auxiliary and styrenes. This asymmetric reaction was also applied in the asymmetric total syntheses of both (-)-(1R,3S)-HPA-12 and (+)-(1S,3R)-HPA-12.
- Xiao, Zu-Feng,Yao, Chuan-Zhi,Kang, Yan-Biao
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p. 6512 - 6514
(2015/02/19)
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- Revised stereochemistry of ceramide-trafficking inhibitor HPA-12 by X-ray crystallography analysis
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In response to Berke?'s report revising the stereochemistry of HPA-12, an important ceramide-trafficking inhibitor that was discovered and synthesized and its stereochemistry determined in 2001, the synthesis and the stereochemistry were reinvestigated. A large-scale synthetic method for HPA-12 based on a Zn-catalyzed asymmetric Mannich-type reaction in water was developed. Single crystals of HPA-12 for X-ray crystallographic analysis were obtained from ethyl propionate/n-hexane, and the stereochemistry was definitely determined to be 1R,3S, consistent with Berke?'s revised structure.
- Ueno, Masaharu,Huang, Yi-Yong,Yamano, Akihito,Kobayashi, Shu
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supporting information
p. 2869 - 2871
(2013/07/19)
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