【作者】 李俊奇；

【导师】 宋庆宝；

【作者基本信息】 浙江工业大学 ， 应用化学， 2010， 硕士

【摘要】 光学纯的α-羰基环氧化物是合成一些天然产物和药物的重要合成砌块,因此开发有效的α,β-不饱和醛酮不对称环氧化方法在有机化学中具有重要意义。到目前为止,已经有很多有价值的反应体系被开发出来用于此反应。有机小分子催化的不对称反应是一个新兴的研究领域,许多有机催化剂在不对称环氧化反应中显示出巨大应用潜力,如聚氨基酸、金鸡钠碱类衍生物和手性β-氨基醇等手性有机催化剂。本文从L-苯丙氨酸甲酯盐酸盐出发,合成出了一系列新型的β-氨基醇类手性催化剂,其结构均经IR、1H NMR、13C NMR和MS表征确认。然后以β-氨基醇为手性催化剂,叔丁基过氧化氢为氧化剂,对查尔酮进行不对称环氧化。其中催化剂20的催化效果最好,产率和光学纯度分别为91.0%, 77.6%。以20为手性催化剂,分别研究了溶剂种类和有机碱(DBU)用量等因素对不对称环氧化反应的影响,我们得出的最佳反应条件为:以正己烷为反应溶剂,TBHP的用量为5 eq,DBU的用量为3 eq。最后研究了该反应底物查尔酮的适用范围。基于手性β-氨基醇,我们又设计合成出了非对称单手性硫脲类催化剂和C2对称双手性(硫)脲类催化剂。手性(硫)脲衍生物具有催化活性高、对映选择性和功能基相容性好、易于制备和修饰、适用范围广等优点,成为近年来研究较多的不对称反应有机催化剂。手性(硫)脲衍生物是各种亲核试剂对亚胺、醛、缺电子烯烃加成反应的非常有效的有机催化剂之一,已成功应用于对映选择性催化Strecker反应、Michael加成反应、Mannich反应、Henry反应等一系列重要的有机合成反应。对合成出的手性(硫)脲类催化剂反应应用和催化活性的研究正在进行当中。更多还原

【Abstract】 The development of efficient methods for the asymmetric epoxidation ofα,β-unsaturated carbonyl compounds is significant in organic synthesis since optically active epoxy ketones are among the most versatile building blocks for access to several natural products and pharmaceuticals. Until now, a variety of valuable systems have been proposed for this reaction. Asymmetric reactions promoted by small organic molecules are an emerging investigated area. A great application potential of organocatalysts has been displayed in asymmetric epoxidation, such as polyamino acid, cinchona alkaloid combinations and chiralβ-amino alcohols.A series of novel chiralβ-amino alcohols were prepared from the hydrogen chloride salt of L-phenylalanine methylester. The structures of these compounds were confirmed by IR, 1H NMR, 13C NMR and MS. All of theβ-amino alcohols were examined as chiral catalysts in the asymmetric epoxidation of chalcones with tertbutyl hydroperoxide as the oxidant. The results obtained showed that the catalyst 20 possessed the best catalytic activity, the yield and optical purity were 91.0%, 77.6%. The effect of different solvents and organic base (DBU) loading were studied with the chiralβ-amino alcohol 20 as the catalyst. The best reaction conditions were: n-hexane as solvent, 5 eq TBHP loading, 3 eq DBU loading. The substrate scope of this reaction was studied in the end.We have also designed and synthesized non-symmetric/single chiral thiourea catalysts and C2 symmetry/double chiral (thio)urea catalysts based on chiralβ-amino alcohols. Chiral (thio)urea derivatives are rapidly emerging as versatile, high catalytic active, low catalyst loading, excellent enantioselective, high functional group tolerant, ease of prepared/modified organocatalyst for the promotion of a wide range of synthetically useful asymmetric processes. Chiral (thio)urea derivatives are very effective organocatalysts for the nuclephilic addition reactions of imines, aldehydes and electron-deficient olefins. They have been successfully applied in varieties of enantioselective organic reactions, such as asymmetric Strecker, Michael addition, Mannich, Henry reactions , etc. The application and catalytic activity of these chiral (thio)urea derivatives are in studing.更多还原