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    題名: 利用共軛的endo-Glycals經由Michael加成反應合成α-2-Deoxy-ulosides及β-Enaminals的衍生物
    Synthesis of α-2-Deoxy-ulosides and β-Enaminals Derivatives by Michael Addition of Conjugated endo-Glycals
    作者: 林子平;Zi-Ping Lin
    貢獻者: 藥物化學研究所博士班
    關鍵詞: 氮醣;醣加成;α-2-Deoxyulosides;β-Enaminals;Michael addition
    日期: 2013-07-24
    上傳時間: 2013-10-02 11:29:53 (UTC+8)
    出版者: 中國醫藥大學
    摘要: Hex-1-en-3-ones與多種含氧的親核試劑,在氫氧化鈉的條件下於室溫反應30分鐘,可得到 Michael 加成產物α-2-deoxyulosides,此醣加成產物具有高產率及高的立體選擇性。此外,改用含硫的親核試劑進行反應時,在0℃的條件下反應90分鐘,也可順利得到高產率及高立體選擇性的α-2-deoxyulosides。
    利用C-2-Formylglycals與一級胺進行Michael加成反應,可順利得到高產率的β-enaminals,隨後用NaBH4及醋酸為溶劑的條件下,卻非預期的對allyl ether進行了還原性裂解反應,可得到一致性的3-deoxy-β-enaminals。β-enaminals在鋅粉及醋酸為溶劑的條件下,會進行四號脫氫,可得到雙烯化合物。此現象歸因於形成亞胺離子態中間體及不同的還原能力所致。
    α-2-Deoxyulosides were synthesized in moderate to good yields by Michael addition of various O-nucleophiles to hex-1-en-3-ones in the presence of NaOH. These glycosyl additions were complete in 30 min at room temperature with high α-stereoselectivity in 53–92% yield. In addition, high α-stereoselectivity was also observed when S-nucleophiles were examined at 0 oC for 90 min.
    β-Enaminals were successfully synthesized in good to excellent yields by the reaction of C-2-formylglycals with primary amines. Subsequent reaction with NaBH4 in HOAc led to unexpected reductive cleavage of allyl ether, i.e. the hydrodealkoxylation took place to produce the corresponding 3-deoxy-β-enaminals. In contrast, the reaction of β-enaminals with Zn/HOAc performed H4-elimination to afford a diene product. The result was attributed to the formation of a common eneiminium ion intermediate, and the different reduction reactivity.
    顯示於類別:[藥物化學研究所] 博碩士論文

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