| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2004: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2003: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
(1)A method for the synthesis cyclic nitrones having multi-oxygen functionalities from herniacetals such as sugars was explored. Thus, the nitrones were prepared by TBAT-mediated desilylative cyclization of ω-mesyloxy-O-tert-butyldiphenylsilyloximes, readily prepared from sugar derivatives by a consecutive treatment with O-tert-butyldiphenylsilylhydroxylamine and with mesyl chloride. As an application of this method, concise synthes of codonopsine, hyacinthacine A_1, and hyacinthacine A_2 were reality accomplished from the cyclic nitrone, which was obtained from protected L-xylose.
(2)A cyclic nitrone derived from (S)-phenylglycinol reacted with allyl alcohols in the presence of MgBr_2OEt_2 to give cycloadducts stereoselectively. The reaction was applied to syntheses of monatin (a natural sweetener) and lycoperdic acid. In contrast to cycloaddition with allyl alcohols, reactions of the cyclic nitrone with a-substituted acrylates in the absence of MgBr_2・OEt_2 gave cycloadducts having op
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posite C4-stcreochemistries. The reaction was used for the synthesis of 4-epi-monatin.
(3)The first syntheses of (-)-funebrine and (-)-funebral were achieved. The syntheses feature sequential formation of the nitrone from methyl glyoxylate with a gulose-derived oxime, transesterification with (E)-crotyl alcohol, and intramolecular cycloaddition. The major cycloadduct was readily elaborated to amino lactone, the key synthetic intermediate of (-)-funebrine and (-)-funebral.
(4)To synthesize (3'R,5'S)-3'-hydroxycotinine, the main metabolite of nicotine, cycloaddition of C-(3-pyridyl)nitrones with (2R)-and (2S)-N-(acryloyl)bornane-10,2-sultam {(2R)-and (2S)-sultam] was examined. Among them, L-gulose-derived nitrone underwent stereoselective cycloaddition with (2S)-sultam to afford the cycloadduct, which was elaborated to (3'R,5'S)-3'-hydroxyeotinine.
(5)Applications of Diets-Alder reactions and cycloaddition of nitrones, representative peri-cyclic reactions to synthesis of heterocyclic compounds were reviewed. Less
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