不对称有机催化反应研究
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摘要
第一部分:有机分子催化的高选择性Aldol反应实现的动态动力学拆分
有机分子催化的,丙酮对β-取代的α-酮酯的Aldol反应,能够通过动态动力学拆分的进程,以较高的产率,优秀的非对映选择性(dr达到99:1)和对映选择性(ee达到98%),获得单一的异构体。反应产物的绝对构型通过X-衍射分析确定。反应经过的动态动力学拆分通过一个可能的过渡态进程进行了描述。
第二部分:新型双官能团催化剂的设计合成及在Michael加成中的应用初探
依据分子识别的概念,设计合成一种新型双官能团催化剂。该催化剂从L-脯氨酸出发,保留四氢吡咯环结构,使用吡啶胺的骨架,通过添加质子酸从而以双氢键对硝基结构产生识别。该催化剂对环己酮和硝基烯的Michael加成具有很好的选择性。
Part 1: Highly Diastereo- and Enantioselective Organocatalytic Addition of Acetone toβ-Substitutedα-Ketoesters via Dynamic Kinetic Resolution
The L-proline catalyzed aldol reactions ofβ-substitutedα-ketoester with acetone proceeded with dynamic kinetic resolution and gave a single diastereoisomer in good yield with excellent diastereoselectivity (dr up to >99:1) and enantioselectivity (ee up to 98%). The absolute configuration of the chiral adduct was assigned by a single crystal X-ray diffraction analysis. A tentativel reaction mechanism was briefly discussed.
Part 2: Design of Tunable Bifunctional Organocatalyst Based on Molecular Recognition and its application in Asymmetric Michael Addition Reaction of Ketones to Nitroolefins
A new catalyst was designed based on molecular recognition. Its application in asymmetry Michael addition reaction was investigated. The possible dual activation model was proposed.
有机分子催化的,丙酮对β-取代的α-酮酯的Aldol反应,能够通过动态动力学拆分的进程,以较高的产率,优秀的非对映选择性(dr达到99:1)和对映选择性(ee达到98%),获得单一的异构体。反应产物的绝对构型通过X-衍射分析确定。反应经过的动态动力学拆分通过一个可能的过渡态进程进行了描述。
第二部分:新型双官能团催化剂的设计合成及在Michael加成中的应用初探
依据分子识别的概念,设计合成一种新型双官能团催化剂。该催化剂从L-脯氨酸出发,保留四氢吡咯环结构,使用吡啶胺的骨架,通过添加质子酸从而以双氢键对硝基结构产生识别。该催化剂对环己酮和硝基烯的Michael加成具有很好的选择性。
Part 1: Highly Diastereo- and Enantioselective Organocatalytic Addition of Acetone toβ-Substitutedα-Ketoesters via Dynamic Kinetic Resolution
The L-proline catalyzed aldol reactions ofβ-substitutedα-ketoester with acetone proceeded with dynamic kinetic resolution and gave a single diastereoisomer in good yield with excellent diastereoselectivity (dr up to >99:1) and enantioselectivity (ee up to 98%). The absolute configuration of the chiral adduct was assigned by a single crystal X-ray diffraction analysis. A tentativel reaction mechanism was briefly discussed.
Part 2: Design of Tunable Bifunctional Organocatalyst Based on Molecular Recognition and its application in Asymmetric Michael Addition Reaction of Ketones to Nitroolefins
A new catalyst was designed based on molecular recognition. Its application in asymmetry Michael addition reaction was investigated. The possible dual activation model was proposed.
引文
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2. (a) Hajos, Z. G.; Parrish, R. D. Asymmetric synthesis of bicyclic intermediates of natural product chemistry. J. Org. Chem. 1974, 39, 1615–1621; (b) Eder, U.; Sauer, G.; Wiechert, R. New Type of Asymmetric Cyclization to Optically Active Steroid CD Partial Structures. Angew. Chem. Int. Ed. 1971, 10, 496–497.
3. Henk, H.; Hans, W. Addition of aromatic thiols to conjugated cycloalkenones, catalyzed by chiral .beta-hydroxy amines. A mechanistic study of homogeneous catalytic asymmetric synthesis. J. Am. Chem. Soc., 1981, 103, 417–430.
4. List, B.; Lerner, R. A.; Barbas III, C. F. Proline-Catalyzed Direct Asymmetric Aldol Reactions. J Am Chem Soc. 2000, 122, 2395–2396.
5. Dalko, P. I.; Moisan, L. In the Golden Age of Organocatalysis. Angew. Chem. Int. Ed. 2004, 43, 5138– 5175
6. Mukherjee, S.; Yang, J. W.; Hoffmann, S.; List. B. Asymmetric Enamine Catalysis. Chem. Rev. 2007, 107, 5471–5569.
7. Franzén, J.; Marigo, M.; Fielenbach, D.; Wabnitz, T. C.; Kj?rsgaard, A.; J?rgensen, K. A. A General Organocatalyst for Directα-Functionalization of Aldehydes: Stereoselective C-C, C-N, C-F, C-Br, and C-S Bond-Forming Reactions. Scope andMechanistic Insights. J. Am. Chem. Soc. 2005, 127, 18296–18304.
8. Terada, M.; Sorimachi, K. Enantioselective Friedel?Crafts Reaction of Electron-Rich Alkenes Catalyzed by Chiral Br?nsted Acid. J. Am. Chem. Soc., 2007, 129, 292–293.
9. (a) Uraguchi, D.; Terada, M. Chiral Br?nsted Acid-Catalyzed Direct Mannich Reactions via Electrophilic Activation. J. Am. Chem. Soc. 2004, 126, 5356–5357; (b) Akiyama, T. Stronger Br?nsted Acids. Chem. Rev. 2007, 107, 5744–5758.
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