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Microwave Assisted Organomolybdenum Lewis Acid Catalyzed Mukaiyama Aldol Reactions

Microwave Assisted Organomolybdenum Lewis Acid Catalyzed Mukaiyama Aldol Reactions. Student : Wanchen Lee. Supervisor : Prof. Shuchun Joyce Yu. 2005 / 07 / 28. Department of Chemistry & Biochemistry Chung Cheng University. Mukaiyama Reaction. Silyl enol ether. Ketone or Aldehyde.

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Microwave Assisted Organomolybdenum Lewis Acid Catalyzed Mukaiyama Aldol Reactions

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  1. Microwave Assisted Organomolybdenum Lewis Acid Catalyzed Mukaiyama Aldol Reactions Student : Wanchen Lee Supervisor : Prof. Shuchun Joyce Yu 2005 / 07 / 28 Department of Chemistry & Biochemistry Chung Cheng University

  2. Mukaiyama Reaction Silyl enol ether Ketone or Aldehyde Mukaiyama, T. et. al. Chem. Lett.1973, 1011-1014

  3. Lewis Acid Catalyzed Mukaiyama Reactions I. Traditional Lewis Acids BF3O(Et)2、AlCl3、InCl3、SnCl4、TiCl4、FeCl3、ZSM-5 Loh, T. P. et. al. Chem. Commun.1996, 1819-1820 Mukaiyama, T. et. al. Chem. Lett.1973, 1011-1014 Saigo, K. et. al. Chem. Lett.1974, 323-326 Sasidharan, M. et. al. Chem. Lett.2003, 32, 624-625 Takeshi, O. et. al. Tetrahedron Lett. 2002, 43, 8959-8962 II. Organometallic Lewis Acids a. Early Transition Metals: Sc (III)、V(IV)、W(0) 1-methyl imidazole Kobayashi, S. et. al. Tetrahedron Lett. 1997, 26, 4559-4562 Chen, C.T. et. al. Synlett.1999, 816-818

  4. b. Late Transition Metals: Fe (II) 、Ru (II) 、Cu (II) Chem. Commun.1992, 1634 Bosnich, B. et. al. Tetrahedron Lett.1992, 39, 5729-5732 Kobayashi, S. et. al. Green Chem.1999, 4, 175-177 Kobayashi, S. et. al. Tetrahedron1999, 55, 8739-8746

  5. III. Lanthanide Metal Triflate (OTf) Complexes : Yb (III) 、La (III) 、Pr (III) 、Nd (III) 、 Sm (III) 、Eu (III) 、Gd (III) 、Dy (III) 、 Ho (III) 、Er (III) Kobayashi, S. et. al. J. Org. Chem.1994, 13, 3590-3596 Kobayashi, S. et. al. Tetrahedron Lett.1997, 26, 4559-4562

  6. IV. Non-Metallic Catalysts a. PS-Formamide b. Ionic liquids c. Brønsted acid ex: citric acid and benzolic acid d. Lewis base ex: lithium acetate、potassium acetate and sodium acetate Ogawa, C.; Sugiura, M.; Kobayashi, S. Chem. Commun.2003, 192-193 Chen, S. L.; Ji, S. J.; Loh, T. P. Tetrahedron Lett. 2004, 375-377 Li, G. L.; Zhao, G. J. Org. Chem.2005, 70, 4272-4278 Mukaiyama, T.; Kawano, Y.; Fujisawa, H. Chem. Lett. 2005, 34, 88-89

  7. Solvent Systems for Mukaiyama Reactions I. Molecular Organic Solvents CH2Cl2、CH3NO2、CH3CN、DMF II. Mixed Solvent System EtOH-H2O、THF-H2O III. Green Solvents R.T. Ionic Liquids (BmimPF6) Water

  8. Indium Trichloride Catalyzed Mukaiyama Aldol Reaction in Water Loh, T. P. et. al. Chem. Commun.1996, 1819-1820

  9. Sc(OTf)3-Catalyzed Aqueous Aldol Reaction in Micellar Systems Kobayashi, S. et. al. Tetrahedron Lett. 1997, 26, 4559-4562

  10. Oxovanadium(IV) BiphenolateCatalyzedMukaiyamaAldol Reaction L = 1-methyl imidazole 10 mol% Chen, C.T. et. al. Synlett.1999, 816-818

  11. [Ru(salen)(NO)H2O]SbF6 Catalyzed Mukaiyama Aldol Reaction Bosnich, B. et. al. Tetrahedron Lett.1992, 39, 5729-5732

  12. Lewis Acid-Surfactant Combined Catalyst Systems (10 mol %) 20 mol % Kobayashi, S. et. al. Green Chem.1999, 4, 175-177

  13. Lanthanide Triflate as Water-Tolerant Lewis Acid Kobayashi, S. et. al. J. Org. Chem.1994, 13, 3590-3596

  14. Polystyrene Supported Formamide Catalyzed Mukaiyama Aldol Reaction Ogawa, C.; Sugiura, M.; Kobayashi, S. Chem. Commun.2003, 192-193

  15. Ionic Liquid Catalyzed Mukaiyama Aldol Reaction Loh, T. P. et. al. Tetrahedron Lett. 2004, 45, 375-377

  16. Motivation I. Traditional Lewis acids are difficult to handle II.Lanthanide metals are relatively expensive III. Low Oxidation State Transition Metals a. Relatively high moisture – and oxygen – stability b. Inexpensive c. Tunable electronic and steric environments around metal Lewis acid center IV. Green Chemistry a. Green solvents R.T. ionic liquids (BmimPF6) and H2O b. Energy saving Catalysis under microwave irradiation

  17. Preparation of Organomolybdenum Catalyst • Thermal Conditions

  18. Microwave Flash Heating Conditions

  19. Crotonaldehyde-Lewis Acid Adduct Childs, R. F. et. al. Can. J. Chem. 1982, 60, 801

  20. Organomolybdenum Lewis Acid Catalyzed Mukaiyama Aldol Reactions under Thermal Conditions

  21. DMF : 3.82 ; 36.7 CH3CN : 3.92 ; 37.5 > >

  22. CH3CN DMF CH3NO2

  23. CH3NO2 CH3CN DMF

  24. CH3CN DMF DMF CH3NO2 CH3CN CH3NO2 DMF : 3.82 ; 36.7 CH3CN : 3.92 ; 37.5 CH3NO2 : 3.46 ; 35.87 > >

  25. CH3CN DMF

  26. DMF CH3CN

  27. Thermal Heating Liquid boiling temperature is always lower than surfacetemperature of container Convection transition

  28. Interactive Characteristic between Materials and Microwave Conductor (Metal Material) Reflective Insulator (Telflon) Transparent Dielectric Materials (Water) Absorptive

  29. Mechanism of Microwave Heating Dipole Rotation

  30. Ionic Conduction

  31. Microwave Flash Heating Microwave energy Digestion bottle Liquid raises temperature quickly

  32. Organomolybdenum Lewis Acid Catalyzed Mukaiyama Aldol Reactions under Microwave Irradiation Conditions

  33. Ionic Liquids Seddon, K. R. et. al. Pure Appl. Chem.2000, 72, 2275–2287

  34. Dipolemomentand Dielectric Constant of Catalytic Solvent Systems Reactivity under Thermal Conditions: DMF > CH3CN > CH3NO2 Reactivity under Microwave : BmimPF6 > DMF > CH3CN

  35. Proposed Mechanism σ-donation

  36. Catalytic Reactivity of [A(2-py)3M(CO)(NO)2]2+ on Mukaiyama Aldol Reaction

  37. Catalytic Reactivity of [A(2-py)3M(CO)(NO)2]2+ on Diels Alder Reaction a:陳宜宏碩士論文 “水溶性有機鎢金屬路易士酸在綠色溶劑及微波中對於Diels-Alde 反應的影響” 中正大學化學研究所, 2003 b: 傅耀賢博士論文 “過渡金屬錯合物觸媒的合成、催化活性以及動力學研究 中正大學化學研究所, 2001 c: 施子芳碩士論文 “有機鎢金屬路易士酸的合成及其催化反應活性之探 中正大學化學研究所, 1998

  38. Conclusions • 本實驗成功地合成出有機金屬鉬路易士酸[O=P(2-py)3Mo(CO)(NO)2](BF4)2， 並將催化劑應用於Mukaiyama醛醇反應，分別在傳統加熱與微波照射系統反 應條件下，對一系列的Mukaiyama醛醇反應具有很好的催化效果。 • 利用微波系統取代傳統加熱法可有效地縮短反應時間與提升能源效率。 • Mukaiyama醛醇反應在不同溶劑系統下，皆有很好的催化效果，且當溶劑系統為低極性與低介電常數時，催化效果比較好。 • 本實驗利用綠色溶劑室溫離子液體(BmimPF6)取代有機溶劑的使用，可有效地進行Mukaiyama醛醇反應，同時也符合綠色化學的宗旨。 • Mukaiyama醛醇反應與Diels-Alder加成反應對[A(2-py)3M(CO)(NO)2]2+催化劑之催化效率，與A和M (A = HO-C、P、O=P和M = Mo、W)有關。對Mukaiyama 醛醇反應而言，當M = Mo時，具較好的催化效果;當A= P(O)時，具較好的催化 效果。對Diels-Alder加成反應而言，當M = W時，具較好的催化效果;當A = P時，具較好的催化效果。 • 本實驗合成出具水溶性的催化劑有機金屬鉬路易士酸，且在水中的溶解度可達23 g/L ，因此，可進一步將有機金屬鉬路易士酸應用於水相的催化系統。

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