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[摘要]:A convergent stereoselective synthesis of a C1/C14 bis-epimer of uprolide D is described in which an intramolecular Barbier-type reaction was employed for macrocyclization with concomitant introduction of the C1 and C14 stereocenters of a fused alpha-methylene lactone ring through an anti-Felkin-Anh transition state. Unlike previous examples of allyl chromium additions, none of the Felkin-Anh derived adduct could be detected. |
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