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具有多氢键给体的金鸡纳碱类硫脲催化剂的合成及其催化性能研究
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摘要
本论文主要研究了具有多氢键给体的金鸡纳碱类硫脲催化剂的设计、合成及其在不对称催化中的应用。以奎宁或奎宁丁为原料,在MsCl, Et3N/NaN3或DPPA/DIAD/PPh3的作用下,将金鸡纳碱中的9-OH通过一步转化得到含有金鸡钠碱骨架的叠氮化合物。该叠氮化合物在三苯基膦和二硫化碳作用下可以很容易地转变成为含有异硫氰基团的金鸡纳碱,进而可以与一系列的氨基醇或单酰基(磺酰基)保护的二胺反应以较高的产率得到含有多个氢键给体的多官能硫脲催化剂。
     为了考察该类催化剂在不对称合成中的应用,我们研究了3-芳基氧化吲哚与苯基烯基砜的Michael加成反应。研究结果表明,以磺酰胺为多氢键给体的奎宁硫脲催化剂能够有效地催化该反应,以中等到较好的收率(52-86% yield)和优秀的对映选择性(83-98%ee)得到带有季碳原子的多取代的手性氧化吲哚化合物。
     此外,该催化剂还能够有效地催化异氰基乙酸酯与靛红的[3+2]环加成反应,以中等到优秀的收率(53-99% yield),优秀的非对映选择性(up to 99:1 dr)和优秀的对映选择性(up to 97% ee)得到手性螺[氧化吲哚-3,5'-嗯哗啉]化合物,有关该反应底物的拓展及结构优化还在进行之中。
This thesis focused on the synthesis of cinchona alkaloid derived bifunctional amine-thiourea catalysts bearing multiple hydrogen-bonding donors, and their initial applications in catalytic asymmetric reactions. The catalysts have been synthesized from quinine or quinidine by the one-pot reaction with triphenylphosphine, diisopropyl azodicarboxylate (DIAD) and diphenylphosphoryl azide (DPPA), then treated with triphenylphosphine and carbon disulfide to form cinchona alkaloid derived isothiocyanate, which was converted to the corresponding catalysts after the reaction with various different ammes.
     In order to illustrate the application of this kind of catalysts, a highly enantioselective Michael addition reaction of 3-aryl-N-Boc oxindoles to phenyl vinyl sulfone has been developed by using quinine derived bifunctional tertiary amine-thiourea-bearing sulfonamide as multiple hydrogen-bonding donor organocatalyst. The reaction scope is substantial and a number of oxindoles could be successfully applied to give the corresponding multifunctional chiral oxindole compounds bearing an all carbon-substituted quaternary stereocenter in moderate to good yields (52-86%) with good to excellent enantioselectivities (83-98% ee).
     Moreover, the quinine derived bifunctional tertiary amine-thiourea-bearing sulfonamide as multiple hydrogen-bonding donor organocatalyst was also found to be effective catalyst for the asymmetric addition reaction of isocyanoacetate to isatins, affording the optical spirooxindoles with moderate to good yield (53-99%), excellent diastereoselectivity (up to 99:1 dr) and excellent enantioselectivity (up to 97% ee).
引文
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