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    Title: α-亞甲基-β−胺基酯進行高立體位向選擇性麥可加成反應
    Other Titles: A highly diastereoselective michael addtion reaction on α-methylene-β-amino ester
    Authors: 李格睿;Lee, Ge-ray
    Contributors: 淡江大學化學學系碩士班
    李世元;Lee, Adam Shih-yuan
    Keywords: 高立體位向性;Diastereoselectivity;Achiral reaction;Michael addition
    Date: 2006
    Issue Date: 2010-01-11 02:38:36 (UTC+8)
    Abstract: β-環內醯胺(β-Lactam)為許多天然物以及藥物的基本架構,而其環上取代基的立體位置更是影響其生物活性功能的重要因素,α-甲基胺-β-胺基酯(α-Aminomethyl-β-amimoester)為β-環內醯胺之前驅物,因此研發其立體選擇性的不對稱合成(Asymmetric synthesis)方法為我們研究的目標之ㄧ;一般是利用反應物本身的立體輔助官能基或添加具有對掌性的(Chiral)催化劑來提升反應的立體選擇性,而我們研究發展在無任何光學活性輔助的環境下(Achiral),利用麥可加成(Michael Addition)反應得到高產率及高立體選擇性的成果。
    我們將一系列外消旋(Racemic)的α-亞甲基-β-胺基酯(α-Methylene-β-amimoester)與胺類化合物(Amine)進行麥可加成反應,在無溶劑(Neat)的狀態下與胺類化合物(5 mL/1 mmol)反應,得到以syn 為主的α-甲基胺-β-胺基酯,另一加入三氟化硼(BF3.OEt2, 1.5 eq.)與胺類化合物(5.0 eq.)反應可得到以anti 為主的α-甲基胺-β-胺基酯;我們將α-甲基胺-β-胺基酯進行環化反應可合成β-環內醯胺,進
    而証明α-甲基胺-β-胺基酯的立體化學結構。
    β-Lactams are the main structural moiety of numerous biological active molecules, and its stereochemistry is one of the key factor that influences the effectiveness. α-Aminomethyl-β-amimoesters are important synthetic precursors for β-lactams, therefore developing its stereoselective reaction is useful in organic synthesis. The asymmetric synthesis is generally achieved by using chiral catalyst or chiral auxiliary to afford the requirement. We develop a new and mild synthetic method which successfully control diastereoselectivity via Michael addition reaction under a achiral reaction condition.
    A series of racemic α-methylene-β-amimoesters was reacted with amines under the reaction conditions. The diastereoselcetivity can be manipulated by treatment of
    the amount of amine and trifloroboran. The α-aminomethyl-β-amimoester was converted to the corresponding β-lactam by treatment of LHMDS. The cyclization not only proves stereochemistry of α-aminomethyl-β-amimoesters, but also improves this diastereoselective reaction much more useful in organic synthesis.
    Appears in Collections:[化學學系暨研究所] 學位論文

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