摘要
1,3-偶极环加成反应是合成五元杂环化合物的常用方法。自1994年过渡金属催化的不对称1,3-偶极环加成反应首次被报道以来,随着研究的深入,利用手性金属络合物作为催化剂直接从非手性的1,3-偶极试剂和烯烃合成具有光学活性的产物成为不对称合成的研究热点之一。
本文的研究内容主用由三部分组成:一、C_2轴对称的双噁唑啉类金属络合物催化的以C,N-二苯基硝酮为偶极体,以缺电子烯烃为亲偶极体的1,3-偶极环加成反应的立体选择性研究;二、以C_1对称的手性1,4-二醇(TADDOL)为配体,合成的TADDOLate-TiX_2类催化剂催化的C,N-二苯基硝酮和缺电子烯烃的反应的立体选择性研究;三、以L-氨基酸为手性源,生成的氨基酸席夫碱为配体,形成的Metal-Salen型席夫碱金属催化的C,N-二苯基硝酮和富电子烯烃乙烯基乙醚的1,3-偶极环加成反应的立体选择性研究。具体研究工作简要概括如下:
本文以5种手性氨基酸R/S-Phg、S-Phe、S-Val、S-Leu和丙二酸为起始原料,经过多步反应合成了五种不同结构的手性双噁唑啉配体S-69a-d和R-69a,利用所合成的5种手性配体,与三氟甲磺酸铜络合,形成铜催化剂S-75a-d,R-75a;与三氟甲磺酸锌络合形成锌催化剂S-76a-d,和醋酸钴络合形成钴催化剂S-77,共十种催化剂体系。上述十种金属催化剂,分别催化了二苯基硝酮与3种缺电子烯烃11a-b,的1,3-偶极环加成反应。系统地考察了催化剂对反应速率,非对映体选择性(包括endo-exo选择性、区域选择性)和对映选择性的影响;同时对配位金属离子、配体结构、亲偶极体的结构、添加物如4?分子筛、溶剂的极性、催化剂的量等因素的影响。
研究结果表明,配体结构对反应的不对称诱导作用,尤其是对映体选择性(ee值)有着重要影响。在5种配体中,由S-苯甘氨酸衍生的69a具有最好的手性诱导作用,表现在S-75a和S-76a的手性催化活性上即在11a-b与1a的催化反应中,可以分别获得80%和76%ee值的产物。
不同金属离子Cu、Zn、Co,由于络合能力的差异,导致其对催化反应的速率和立体选择性影响也发生明显改变。配位金属为Cu~(2+)的催化体系表现出反应时间明显缩短、优秀的endo、exo选择性和对映体选择性;配位金属为Zn~(2+)的催化体系表现出中等的反应速率和中等的非对映体选择性和对映体选择性;当金属离子为Co~(2+)时,由于其不能有效的与配体络合,导致其失去催化活性。
亲偶极体烯烃的结构对反应的立体选择性有重要的影响。烯烃11b由于其相邻C=O容易与催化体系形成稳定的活化络合物,有利于配体的手性诱导,因此催化反应具有较高的对映选择性,产物的对映体过量值大于65%。而烯烃11a由于不饱和双键上CH3的电子效应和空间位阻效应,不利于催化体系与其形成稳定的活化络合物,导致一些催化反应的对映体选择性不理想。
反应溶剂对催化反应的非对映体选择性和对映选择性有重要影响。实验所示溶剂中,二氯甲烷是一种较好的1,3-偶极反应溶剂。
本文选用未见文献报道的C1-对称轴的催化剂手性配体,该配体以L-酒石酸为起始原料,由与苯甲醛缩合保护的酒石酸酯与格式试剂溴化苯基镁反应得到。该种配体分别与两种钛盐络合,形成了两种金属催化剂TADDOLate-TiCl_2 92a和TADDOLate-Ti(OTos)_2 92b,考察了它们对1a与11b的1,3-偶极环加成反应的催化效果以及催化剂的量、溶剂、金属催化剂中的阴离子Cl-和-OTos等因素对反应的区域选择性、endo/exo选择性和对映体选择性的影响。
实验结果表明,在无催化剂存在的条件下,二苯基硝酮与11b反应没有区域选择性。加入催化剂92a或92b后该反应的区域选择性明显提高,当催化剂的量增加到50mol%时,该反应的4-位异构体达到了100%。
催化剂92a或92b的加入明显改变了反应的endo-exo选择性。与空白反应相比,催化反应的endo-exo选择性发生了翻转,当催化剂92a的量增加到100mol%时, exo与endo的比值达到4:96,对映体过量值达到69%。
溶剂的极性对反应的立体选择性有很大的影响,在10mol%92a的催化作用下,随着溶剂极性的增加,反应的选择性逐渐提高,甲苯和二氯甲烷同三氯甲烷、四氯化碳、乙腈相比是催化效果较好的两种溶剂。
本文以氨基酸和氨基酸苄酯为手性源,合成了10种氨基酸席夫碱-Zn、Cu络合物,10种氨基酸苄酯席夫碱- Cu(OTf)_2、Ti(i-OPr)_4的金属络合物,并以C,N-二苯基硝酮与富电子烯烃乙烯基乙醚的环加成反应为模版反应,考察了两类催化剂的催化性能。结论如下:
以氨基酸席夫碱-Zn、Cu络合物为催化剂时,如果反应在CH_2Cl_2溶剂中进行,由于催化剂不溶,即反应在非均相条件下进行,催化剂没有表现出催化活性。如果反应以DMF为溶剂,则催化反应可在均相条件下完成,此时可以得到endo-选择性的主产物,endo:exo产物比例可以达到82:18-100:0。金属离子对反应的endo/exo选择性有较大影响,配体相同时,Cu络合物的催化性能明显优于Zn的络合物;配体的结构也会对反应的选择性产生影响,金属相同时,2-羟基-1-萘醛同氨基酸缩合而成的席夫碱的催化效果比水杨醛席夫碱作配体的催化效果好;当金属及醛均相同时,氨基酸的分子量越小,催化活性越高。
氨基酸苄酯席夫碱Cu~(2+)络合物可以大大提高二苯基硝酮与乙烯基乙醚的反应速度,由空白反应的72小时降为10分钟,但产物的立体选择性不好。降低反应温度立体选择性有所改进,但反应条件比较苛刻。
氨基酸苄酯席夫碱Ti络合物在非极性溶剂中有良好的溶解性,它们催化二苯基硝酮与乙烯基乙醚的环加成反应时具有良好的立体选择性,得到endo-异构体占优势的产物。配体结构以及中心金属离子的差异对催化效果无明显影响。
由此可见氨基酸席夫碱金属络合物催化上述反应倾向于生成endo-异构体优势产物,而不论氨基酸的种类及邻羟基芳香醛种类。在目前文献中还未见以endo-异构体为优势产物的催化剂报道。
The addition of a 1,3-dipole(1,3-DC) to an alkene for the synthesis of five-membered rings is a classic reaction in organic chemistry. The intense study of enantioselective 1,3-dipolar cycloaddition methodologies has provided organic chemists with the tools necessary to synthesize a variety of chiral heterocycles in high enantioenriched forms on chiral Lewis acid-catalyzed or chiral metal-mediated 1,3-dipolar cycloaddition methodologies, after the first asymmetric 1,3-dipolar cycloaddition reaction by transition-metal catalyzed was reported in 1994.
The paper is made up of three sections: one is study on the steroselectivity of 1,3-DC of C, N-diphenylnitrone andα,β-unsaturated imides catalyzed by C2-symmetrical chiral bisoxazolines metal complexes; the other is 1,3- DC reactions of C, N-diphenylnitrone andα,β-unsaturated imide catalyzed by C1-symmetrical Ti(OTos)2- and TiCl_2-TADDOLate; the third section is amino acids Schiff bases metals- catalyzed 1,3- DC reactions of C, N-diphenylnitrone with electron-rich alkene ethyl vinyl ether.
In this paper, a series of chiral bisoxazolines derived from S-amino acids, S-69a-d and R-69a are synthesized. The five different bisoxazolines complexed with Cu(II), Zn(II) and Co(II) formed ten chiral metal complexes catalysts, are tested to catalyze the 1,3-DC reactions of 3-N-alk-2-enoyloxazolidinones 11a-b with C,N-diphenylnitrone 1b.
The 1,3-DC reactions between 3-N-alk-2-enoyloxazolidinones 11a-b with nitrone 1b catalyzed by Cu(OTf)_2-, Zn(OTf)_2- and Co(CH_3COO)_2-bisoxazolines are tested and the influence of catalysts on the reaction rate, diastereoselectivity (including regioselectivity and endo-exo selectivity) and enantioselectivity were investigated. These reactions were investigated under different conditions such as the metal ions,the structure of chiral ligands, solvents of different polarity, molecular sieves, and catalyst dosages. The present results have shown that chrial ligands have an important effect on the endo、exo-selectivity and enantioselectivity of the 1,3-DC process and the ligand 69a derived from S-Phe can induce the most excellent stereoselectivity 1,3-DC reactions, its metal complexes S-75a and S-76a-catalyzed the 1,3-DC reactions between 11a, 11b and 1b proceed with a high of enantioselectivity, up to 80% and 76% respectively. Metal ions are important factor on both reaction rate and stereoselectivity of the catalyzed reaction of 11 and 1b. The polarity of solvents also has a crucial effect on the stereoselectivity of the 1,3-DC reactions. Dichlormethane is a better solvent than the other solvent.
We also studied the 1,3-DC reactions of C, N- diphenylnitrone 1a and 3-N-alk-2-enoyloxazolidinones 11b catalyzed using C1-symmetrical TADDOLate- TiX2 as chiral metal catalysts. The influence of different catalysts, catalyst dosages, solvents of different polarity and Cl- and -OTos of metal complexes on the regio-, endo-exo and enantioselectivity are deeply investigated. The studied results have shown that the stereoselectivity is decided according by the combined factors. Without regioselectivity of the blank reaction of C, N-diphenylnitrone 1a and 3-acryloyl-oxazolidin-2-one 11b is an unexcepted example in the 1,3-DC reactions. At the presence of TADDOLate-TiCl_2 catalysts, a remarkable improvement of the regioselectivity is observed. 100% regioselectivity isomer can be obtained when increasing the catalyst amount to 50mol%. The endo/exo selectivity of this reaction is obviously reversed compared with the blank reaction. A high endo/exo and enantioselectivity is observed by increasing the catalyst amount and the best endo/exo ratio and ee% is 96:4 and 69% respectively when using 100mol% 92a as a catalyst. The stereoselectivity of reaction of C, N-diphenylnitrone 1a and 3-acryloyl- oxazolidin-2-one 11b has also relations with solvents. Increasing the polarity of solvent can lead to a high stereoselectivity in the presence of 10mol% 92a. PhCH_3 and CH_2Cl_2 are better solvents in all solvents for this reaction. The stereoselectivity of this reaction is influenced by anions Cl- and -OTos of catalysts. If the Cl~- of the catalyst is substituted with ~-OTos ligand of the same catalyst amount, slightly changed selectivities are observed.
As a new class of potential catalysts for 1,3-dipolar cycloaddition reaction, we synthesized two families of Schiff base metal complexes: one is Cu(II) and Zn(II) complexes 95a-f、97a-d of Schiff bases derived from L-amino acids, the other is Cu(TOf)_2 complex 102a and Ti(OiPr)_4 complexes 103a-g、104a-b of L-amino acids benzyl esters Schiff bases. Twenty catalysts have been evaluated for their catalytic activities in 1,3-dipolar cycloaddition reaction between C,N-diphenylnitrone 1b and ethyl vinyl ether 7a as a model reaction. Ten L- amino acids Schiff bases Cu(II) and Zn(II) complexes 95a-f、97a-d were synthesized by solid-phase mothod, characterized, and evaluated for their catalytic activities in model reaction under both heterogeneous and homogeneous conditions. Excellent reaction results were found in the presence of catalyst 97a (20 mol%) with 100% endo-isoazolidines produced, comparing with predominantly exo-isoazolidine produced without a catalyst. Importantly, when Cu(TOf)_2- Schiff base complex 102a as catalyst in situ conditions, the reaction rate is found to be enhanced remarkably by about 1700 times (the reaction time is shorted from 72 hours to 10 minutes) although the product is obtained with 93% exo-product at room temperature and by optimizing the reaction conditions to moderately low the reaction rate and lengthen the reaction time to 10 h, the diastereoselectivity could be improved to 72: 28 ratio of the endo- and exo- cycloadducts with 100% conversion. As the present of a catalyst 103a or 103b-g, 104a-b, 90% endo-product can be obtained at 10℃and especially, when 20mol% 104b as a catalyst, up to 98% endo- diastereomer can be achieved.
引文
[1] a) HUISGEN R. 1,3-Dipolar Cycloadditions Past and Future[J]. Angewa-ndte Chemie International Edition, 1963, 2(10): 565-598. b) HUISGEN R.Kinetics and Mechanism of 1,3-Dipolar Cycloadditions[J]. Angewandte C-hemie International Edition, 1963, 2(11): 633-645.
[2] a) LABBE G. Decomposition and Addition Reactions of Organic Azides [J]. Chemical Reviews, 1969, 69(3): 345-363. b) PADWA A. Intramolec-ular 1,3-Dipolar Cycloaddition Reactions[J]. Angewandte Chemie Internat-ional Edition, 1976, 15(3): 123-136.
[3]陈庆华.1,3-偶极环加成反应在有机合成方面的新进展[J].有机化学,1988,8(3):193-205.
[4] HOFFMANN R, WOODWARD R B. Orbital Symmetries and Endo-exo Relationships Inconcerted Cycloaddition Reactions[J]. Journal of the Ame-rican Chemical Society, 1965, 87(19): 4388-4389.
[5] HOUK K N, SIMS J, CHARLES R. Origin of Reactivity, Regioselectivi-ty and Periselectivity in 1,3-dipolar Cycloadditions[J]. Journal of the Am-erican Chemical Society, 1973, 95(3): 7301-7315.
[6] FIRESTONE R A. Mechanism of 1,3-Dipolar Cycloadditions[J]. Journal of Organic Chemistry, 1968, 33(6): 2285-2290.
[7] HUISGEN R. Mechansm of 1,3-Dipolar Cycloadditions. Reply[J]. Journalof Organic Chemistry, 1968, 33(6): 2291-2297.
[8] PADWA A. 1,3-Dipolar Cycloaddition Chemistry[M]. New York: Wiley, 1984: 1-176.
[9] GOTHELF K V, J?RGENSEN K A. Asymmetric 1,3-Dipolar Cycloaddit-ion Reactions[J]. Chemical Reviews, 1998, 98(2): 863-909.
[10] ITO M, MAEDA M, KIBAYASHI C. Diastereofacial Selectivity in Intermole- cular Nitrone Cycloadditions to Chiral Ally1 Ethers.Application to Chiral Syn- thesis of Coniine[J]. Tetahedron Letters, 1992, 33(26): 3765-3768.
[11] GOTI A, CICCHI S, CACCIARINI M, et al. Straightforward Access to Enantiomerically Pure,Highly Functionalized Pyrrolizidines by Cycloadditi-on of Maleic Acid Esters to Pyrroline N-Oxides Derived from Tartaric,Malic and Aspartic Acids - Synthesis of (-)-Hastanecine,7-epi-Croalbineci-ne and (-)-Croalbinecine[J]. European Journal of Organic Chemistry, 2000,(21): 3633-3645.
[12] KANEMASA S, KANAI T. Lewis Acid-Catalyzed Enantioselective 1,3-D-ipolar Cycloadditions of Diazoalkane: Chiral Ligand/Achiral Auxiliary Co-operative Chirality Control[J]. Journal of the American Chemical Society,2000, 122(43): 10710-10711.
[13] KAGAN H B, RIANT O. Catalytic Asymmetric Diels Alder Reactions [J]. Chemical Reviews, 1992, 92(5): 1007-1019.
[14] KANEMASA S, UEMURA T, WADA E. Lewis Acid-Catalyzed Nitrone Cycloadditions to Bidentate and Tridentateα,β-unsaturated Ketones. High Rate Acceleration, Absolutely Endo-selective and Regioselective Reactions[J]. Tetahedron Letters, 1992, 33(51): 7889-7892.
[15] DEGIORGIS F, LOMBARDO M, TROMBINI C. Synthesis of Four Ster-eo-Isomers of 5-Amino-2,5-Dideoxy-Heptono-1,5-Lactams[J]. Tetahedron, 1997, 53(34): 11721-11730.
[16] GOTHELF K V, J?RGENSEN K A. Transition-metal Catalyzed Asymm-etric 1,3-dipolar Cycloaddition Reactions between Alkenes and Nitrones [J]. Journal of Organic Chemistry, 1994, 59(19): 5687-5691.
[17] GOTHELF K V, HAZELL R G, J?RGENSEN K A. Control of Diastereo- and Enantioelectivity in Metal-catalyzed 1,3-Dipolar Cycloaddition Re-actions of Nitrones with Alkenes. Experimental and Theoretical Investiga-tions[J]. Journal of Organic Chemistry, 1996, 61(1): 346-355.
[18] SEERDEN J G, REIMER A W S, SCHEEREN H W. Asymmetric 1,3- Dipolar Cycloaddition of Nitrones with Ketene Acetals Catalyzed by Chi-ral Oxazaborolidines[J]. Tetahedron Letters, 1994, 35(25): 4419-4422.
[19] SEERDEN J G, BOEREN M M, SCHEEREN H W. 1,3-Dipolar Cycloa-ddition Reactions of Nitrones with Alkyl Vinyl Ethers Catalyzed by Chi-ral Oxazaborolidines[J]. Tetahedron, 1997, 53(34): 11843-11852.
[20] SIMONSEN K B, BAYN P, HAZELL R G, et al. Catalytic Enantioselec-tive Inverse-Electron Demand 1,3-Dipolar Cycloaddition Reactions of Nit-rones with Alkenes[J]. Journal of the American Chemical Society, 1999, 121(16): 3845-3853.
[21] JENSEN K B, ROBERSON M, J?RGENSEN K A. Catalytic Enantiosel-ective 1,3-Dipolar Cycloaddition Reactions of Cyclic Nitrones: A Simple Approach for the Formation of Optically Active Isoquinoline Derivatives[J]. Journal of Organic Chemistry, 2000, 65(26): 9080-9084.
[22] GOTHELF K V, HAZELL R G, J?RGENSEN K A. Molecular Sieve Dependent Absolute Stereoselectivity in Asymmetric Catalytic 1,3-DipolarCycloaddition Reactions[J]. Journal of Organic Chemistry, 1998, 63(16): 5483-5488.
[23] DESIMON G, FAITA G, MORTONI A, et al. 1,3-Dipolar Cycloaddition Catalyzed by Bis(Oxazoline)-Magnesium-Based Chiral Complexes. The I-mportance of a Mg(II) Counterion[J]. Tetahedron Letters, 1999, 40(38): 2001-2004.
[24] CROSIGNANI S, DESIMONI G, FAITA G, et al. Chiral Amplification inDiels-Alder and 1,3-Dipolar Cycloadditions Catalyzed by Bis(Oxazoline) Zn(II)-Based Chiral Complexes[J]. Tetahedron Letters, 1999, 40(38): 7007-7010.
[25] DESIMONI G, FAITA G, MELLA M, et al. Control of Diastereoselectityin Metal-Catalyzed 1,3-Dipolar Cycloaddition between Diphenylnitrone a-nd Chiral Auxiliary-Substituted Crotonyl Amide[J]. Tetahedron, 1999, 55(28): 8509-8524.
[26] SEEBACH D, BECK A K, HECKEL A. TADDOLs, Their Derivatives, and TADDOL Analogues: Versatile Chiral Auxiliaries[J]. Angewandte Ch-emie International Edition, 2001, 40(1): 92-138.
[27] JENSEN K B, GOTHELF K V, HAZELL R G, et al. Improvement of TADDOLate-TiCl2-Catalyzed 1,3-Dipolar Nitrone Cycloaddition Reactions by Substitution of the Oxazolidinone Auxiliary of the Alkene with Succi-nimide[J]. Journal of Organic Chemistry, 1997, 62(8): 2471-2477.
[28] GOTHELF K V, J?RGENSEN K A. On the Trans-Cis Controversy in Ti-TADDOLate-Catalysed Cycloadditions. Experimental Indications for theStructure of the Reactive Catalyst-Substrate Intermediate[J]. Journal of theChemical Society. Perkin transactions 2, 1997, (1): 111-115.
[29] SEEBACH D, DAHINDEN R, MARTI R E, et al. On the Ti-TADDOL-ate-Catalyzed Diels-Alder Addition of 3-Butenoyl-1,3-Oxazolidin-2-One toCyclopentadiene. General Features of Ti-BINOLate- and Ti-TADDOLate- Mediated Reactions[J]. Journal of Organic Chemistry, 1995, 60(6): 1788- 1799.
[30] HAASE C, SARKO C R, DIMARE M. TADDOL-Based Titanium Catal-ysts and Their Adducts: Understanding Asymmetric Catalysis of Diels-Al-der Reactions[J]. Journal of Organic Chemistry, 1995, 60(6): 1777-1787.
[31] GARCA J I, MERINO V M, MAYORAL J A. Quantum Chemical Insig-hts into the Mechanism of the TADDOL-TiCl2 Catalyzed Diels-Alder Re-actions[J]. Journal of Organic Chemistry, 1998, 63(7): 2321-2324.
[32] GOTHELF K V, HAZELL R G, J?RGENSEN K A. Crystal Structure ofa Chiral Titanium-Catalyst-Alkene Complex. The Intermediate in CatalyticAsymmetric Diels-Alder and 1,3-Dipolar Cycloaddition Reactions[J]. Jour-nal of the American Chemical Society, 1995, 117(15): 4435-4436.
[33] GOTHELF K V, THOMSEN I, J?RGENSEN K A. A Highly Diastereos-elective and Enantioselective Ti(OTos)2-TADDOLate-Catalyzed 1,3-DipolarCycloaddition Reaction of Alkenes with Nitrones[J]. Journal of the Amer-ican Chemical Society, 1996, 118(1): 59-64.
[34] JENSEN K B, GOTHELF K V, J?RGENSEN K A. Control of Regio-, Diastereo-, and Enantioselectivity in the [Ti(OTs),(TADDOLato)]-Catalyzed1,3-Dipolar Cycloaddition Reaction between 3-Acryloyloxazolidin-2-One a-nd Nitrones[J]. Helvetica Chimica Acta, 1997, 80(7): 2039-2046.
[35] SEEBACH D, MARTI R F, HINTERMANN T. Polymer- and DendrimerBound Ti-TADDOLates in Catalytic (and Stoichiometric) Enantioselective Reactions: Are Pentacoordinate Cationic Ti Complexes the Catalytically Active Species?[J]. Helvetica Chimica Acta, 1996, 79(6): 1710-1740.
[36] HECKEL A, SEEBACH D. Immobilization of TADDOL with a High D-egree of Loading on Porous Silica Gel and First Applications in Enantio-selective Catalysis[J]. Angewandte Chemie International Edition, 2000, 39(1): 163-165.
[37] ELLIS W W, GAVRILOVA A, SANDS L L, et al. Homogeneous Catal-ysis. Metallocene Catalysts for [3+2] Nitrone?Olefin Cycloaddition React-ions[J]. Organometallics, 1999, 18(3): 332-338.
[38] BAYON P, MARCH P, ESPINOSA M, et al. Use of chiral Ti(IV) Com-plexes in The Cycloaddition of C,N-Diphenylnitrone to Tert-Butyl Vinyl Ether[J]. Tetrahedron: Asymmetry, 2000, 11(8): 1757-1765.
[39] KANEMASA S, ODERAOTOSHI Y, SAKAGUCHI S I, et al. Transition-Metal Aqua Complexes of 4,6-Dibenzofurandiyl-2,2'-bis(4-phenyloxazolin-e). Effective Catalysis in Diels?Alder Reactions Showing Excellent Enan-tioselectivity, Extreme Chiral Amplification, and High Tolerance to Water,Alcohols, Amines, and Acids[J]. Journal of the American Chemical Soci-ety, 1998, 120(13): 3074-3088.
[40] KANEMASA S, ODERAOTOSHI Y, TANAKA J, et al. Highly Endo- a-nd Enantioselective Asymmetric Nitrone Cycloadditions Catalyzed by theAqua Complex of 4,6-Dibenzofurandiyl-2,2'-Bis(4-Phenyl-Oxazoline)?Nick-el(II) Perchlorate. Transition Structure Based on Dramatic Effect of MS 4A on Selectivities[J]. Journal of American Chemical Society, 1998, 120(47): 12355-12356.
[41] JENSEN K B, HAZELL R G, J?RGENSEN K A. Copper(II)-Bisoxazoli-ne Catalyzed Asymmetric 1,3-Dipolar Cycloaddition Reactions of Nitroneswith Electron-Rich Alkenes[J]. Journal of Organic Chemistry, 1999, 64(7):2353-2360.
[42] HORI K, KODAMA H, OHM T, et al. Palladium-Catalyzed Asymmetric1,3-Dipolar Cycloaddition of Nitrones to Olefins[J]. Tetahedron Letters, 1996, 37(33): 5947-5950.
[43] HORI K, KODAMA H, OHM T, et al. Palladium(II)-Catalyzed Asymme-tric 1,3-Dipolar Cycloaddition of Nitrones to 3-Alkenoyl-1,3-Oxazolidin-2-Ones[J]. Journal of Organic Chemistry, 1999, 64(14): 5017-5023.
[44] HORI K, ITO J, OHM T, et al. Palladium(II)-Catalyzed 1,3-Dipolar Cyc-loaddition of Nitrones with Enol Ethers[J]. Tetahedron, 1998, 54(42): 12737-12744.
[45] UKAJI Y, TANIGUCHI K, SADA K, et al. Enantio- and Diastereoselect-ive Synthesis of Isoxazolidines by Asymmetric 1,3-Dipolar Cycloaddition of Nitrones[J]. Chemistry Letters, 1997, 26(6): 547-548.
[46] BLANCO A S, GOTHELF K V, J?RGENSEN K A. Lanthanide-Catalyz-ed Endo- and Enantioselective 1,3-Dipolar Cycloaddition Reactions of Ni-trones with Alkenes[J]. Tetahedron Letters, 1997, 38(45): 7923-7926.
[47] KOBAYASHI S, AKIYAMA R, KAWAMURA M, et al. Lanthanide Trifl-ate-Catalyzed Three-Component Coupling Reactions of Aldehydes,Hydro- xylamines, and Alkenes Leading to Isoxazolidine Derivatives[J]. Chemistr-y Letters, 1997, 26(10): 1039-1040.
[48] KAWAMURA M, KOBAYASHI S. A Switch of Enantiofacial Selectivity in Chiral Ytterbium-Catalyzed 1,3-Dipolar Cycloaddition Reactions[J]. Tet-ahedron Letters, 1999, 40(16): 3213-3216.
[49] KODAMA H, ITO J, HORI K, et al. Lanthanide-Catalyzed Asymmetric 1,3-Dipolar Cycloaddition of Nitrones to Alkenes using 3,3'-Bis(2-Oxazol-yl)-1,1'-Bi-2-Naphthol (BINOL-Box)Ligands[J]. Journal of Organometallic Chemistry, 2000, 603(1): 6-12.
[50] KOBAYASHI S, KAWAMURA M. Catalytic Enantioselective 1,3-Dipolar Cycloadditions between Nitrones and Alkenes Using a Novel HeterochiralYtterbium(III) Catalyst[J]. Journal of American Chemical Society, 1998, 120(23): 5840-5841.
[51] HASHIMOTO T, OMOTE M, KANO T, et al. Asymmetric 1,3-Dipolar Cycloadditions of Nitrones and Methacrolein Catalyzed by Chiral Bis-Tit-anium Lewis Acid: A Dramatic Effect of N-Substituent on Nitrone[J]. O-rganic Letters, 2007, 9(23): 4805-4808.
[52] SHINTANI R, MURAKAMI M, HAYASHI T.γ-Methylidene-δ-Valerolact-ones as a Coupling Partner for Cycloaddition: Palladium-Catalyzed [4+3] Cycloaddition with Nitrones[J]. Journal of the American Chemical Societ-y, 2007, 129(41): 12356-12357.
[53] SHINTANI R, PARK S, DUAN W L, et al. Palladium-Catalyzed Asym-metric [3+3] Cycloaddition of Trimethylenemethane Derivatives with Nitr-ones[J]. Angewandte Chemie International Edition, 2007, 46(31): 5901- 5903.
[54] CARMONA D, LAMATA M, VIGURI F, et al. Asymmetric 1,3-Dipolar Cycloaddition Reaction betweenα,β-Unsaturated Aldehydes and Nitrones Catalyzed by Well-Defined Iridium or Rhodium Catalysts[J]. Advanced S-ynthesis and Catalysis, 2007, 349(10): 1751-1758.
[55] KANG Y B, SUN X L, TANG Y. Highly Enantioselective and Diastere-oselective Cycloaddition of Cyclopropanes with Nitrones and Its Applicat-ionin the Kinetic Resolution of 2-Substituted Cyclopropane-1,1-Dicarboxy-lates[J]. Angewandte Chemie International Edition, 2007, 46(21): 3918- 3921.
[56] SIBI M P, MANYEM S, PALENCIA H. Fluxional Additives: A Second Generation Control in Enantioselective Catalysis[J]. Journal of American Chemical Society, 2006, 128(42): 13660-13661.
[57] EVANS D A, SONG H J, FANDRICK K R. Enantioselective Nitrone C-ycloadditions ofα,β-Unsaturated 2-Acyl Imidazoles Catalyzed by Bis(O-xazolinyl) Pyridine-Cerium(IV) Triflate Complexes[J]. Organic Letters, 2006, 8(15): 3351-3354.
[58] CARMONA D, LAMATA M P, VIGURI F, et al. Enantioselective 1,3-D-ipolar Cycloaddition of Nitrones to Methacrolein Catalyzed by (CMe)M{(R)-Prophos} Containing Complexes (M = Rh, Ir; (R)-Prophos = 1,2-Bis(Diphenylphosphino)Propane): On the Origin of the Enantioselectivity[J]. Journal of the American Chemical Society, 2005, 127(38): 13386-13398.
[59] KANO T, HASHIMOTO T, MARUOKA K. Asymmetric 1,3-Dipolar Cy-cloaddition Reaction of Nitrones and Acrolein with a Bis-Titanium Catal-yst as Chiral Lewis Acid[J]. Journal of the American Chemical Society, 2005, 127(34): 11926-11927.
[60] DESIMONI G, FAITA G, GUALA M, et al. A New Pyridine-2,6-Bis(Ox-azoline) for Efficient and Flexible Lanthanide-Based Catalysts of Enantio-selective Reactions with 3-Alkenoyl-2-Oxazolidinones[J]. Chemistry—A European Journal, 2005, 11(13): 3816-3824.
[61] DESIMONI G, FAITA G, MELLA M, et al. In Search of exo-Selective Catalysts for Enantioselective 1,3-Dipolar Cycloaddition between Acryloy-loxazolidinone and Diphenylnitrone[J]. European Journal of Organic Che-mistry, 2005, (6): 1020-1027.
[62] SIBI M P, MA Z, JASPERSE C P. Enantioselective Addition of Nitronesto Activated Cyclopropanes[J]. Journal of the American Chemical Societ-y, 2005, 127(16): 5764-5765.
[63] SUGA H, NAKAJIMA T, ITOH K, et al. Highly Exo-Selective and Ena-ntioselective Cycloaddition Reactions of Nitrones Catalyzed by a Chiral Binaphthyldiimine-Ni(II) Complex[J]. Organic Letters, 2005, 7(7): 1431-1434.
[64] CHEN W, YUAN X H, LI R, et al. Organocatalytic and Stereoselective[3+2] Cycloadditions of Azomethine Imines withα,β-Unsaturated Aldehy-des[J]. Advanced Synthesis and Catalysis, 2006, 348(14): 1818-1822.
[65] CHEN W, DU W, DUAN Y Z, et al. Enantioselective 1,3-Dipolar Cycl-oaddition of Cyclic Enones Catalyzed by Multifunctional Primary Amines:Beneficial Effects of Hydrogen Bonding[J]. Angewandte Chemie Internati-onal Edition, 2007, 46(40): 7667-7670.
[66] SUGA H, FUNYU A, KAKEHI A, et al. Highly Enantioselective and Diastereoselective 1,3-Dipolar Cycloaddition Reactions between Azomethi-ne Imines and 3-Acryloyl-2-Oxazolidinone Catalyzed by Binaphthyldiimin-e?Ni(II) Complexes[J]. Organic Letters, 2007, 9(1): 97-100.
[67] NAJERA C, SANSANO J M. Catalytic Enantioselective 1,3-Dipolar Cyc-loaddition Reaction of Azomethine Ylides and Alkenes: The Direct Strat-egy to Prepare Enantioenriched Highly Substituted Proline Derivatives[J].Angewandte Chemie International Edition, 2005, 44(39): 6272-6276.
[68] PANDEY G, BANERJEE P, GADRE S R. Construction of Enantiopure Pyrrolidine Ring System via Asymmetric [3+2]-Cycloaddition of Azomet-hine Ylides[J]. Chemical Reviews, 2006, 106(11): 4484-4517.
[69] TERESA P M. Conjugated Azomethine Ylides[J]. European Journal of O-rganic Chemistry, 2006, (13): 2873-2888.
[70] BONIN M, CHAUVEAU A, MICOUIN L. Asymmetric 1,3-Dipolar Cycl-oadditions of Cyclic Stabilized Ylides Derived from Chiral 1,2-Amino A-lcohols[J]. Synlett, 2006, (15): 2349-2363.
[71] HUSINEC S, SAVIC V. Chiral Catalysts in The Stereoselective Synthesisof Pyrrolidine Derivatives via Metallo-Azomethine Ylides[J]. Tetrahedron:Asymmetry, 2005, 16(12): 2047-2061.
[72] COLDHAM I, HUFTON R. Intramolecular Dipolar Cycloaddition Reactions of Azomethine Ylides[J]. Chemical Reviews, 2005, 105(7): 2765-2809.
[73] TSUTSUI H, SHIMADA N, ABE T, et al. Catalytic Enantioselective Ta-ndem Carbonyl Ylide Formation/1,3-Dipolar Cycloaddition Reactions ofα-Diazo Ketones with Aromatic Aldehydes using Dirhodium(II) Tetrakis [N-Benzene-Fused-Phthaloyl-(S)-Valinate][J]. Advanced Synthesis and Cat-alysis, 2007, 349(4-5): 521-526.
[74] SUGA H, ISHIMOTO D, HIGUCHI S, et al. Dipole-LUMO/Dipolarophil-e-HOMO Controlled Asymmetric Cycloadditions of Carbonyl Ylides Cata-lyzed by Chiral Lewis Acids[J]. Organic Letters, 2007, 9(21): 4359-4362.
[75] TORSSELL S, SOMFAI P. 1,3-Dipolar Cycloadditions of Carbonyl Ylidesto Aldimines: Scope, Limitations and Asymmetric Cycloadditions[J]. Adv-anced Synthesis and Catalysis, 2006, 348(16-17): 2421-2430.
[76] SUGA H, SUZUKI T, INOUE K, et al. Asymmetric Cycloaddition Reac-tions between 2-Benzopyrylium-4-Olates and 3-(2-Alkenoyl)-2-Oxazolidin-ones In the Presence of 2,6-Bis(Oxazolinyl) Pyridine-Lanthanoid Comple-xes[J]. Tetahedron, 2006, 62(39): 9218-9225.
[77] HODGSON D M, BRUCKL T, GLEN R, et al. Catalytic Enantioselectiv-e Intermolecular Cycloadditions of 2-Diazo-3,6-Diketoester-Derived Carbo-nyl Ylides with Alkene Dipolarophiles[J]. Proceedings of the National A-cademy of Sciences, 2004, 101(15): 5450-5454.
[78] HODGSON D M, LABANDE A H, PIERARD F Y, et al. The Scope of Catalytic Enantioselective Tandem Carbonyl Ylide Formation-Intramole-cular [3+2] Cycloadditions[J]. Journal of Organic Chemistry, 2003, 68(16):6153-6159.
[79] SUGA H, INOUE K, INOUE S, et al. Highly Enantioselective 1,3-Dipol-ar Cycloaddition Reactions of 2-Benzopyrylium-4-Olate Catalyzed by Chi-ral Lewis Acids[J]. Journal of the American Chemical Society, 2002, 124(50): 14836-14837.
[80] HODGSON D M, STUPPLE P A, JOHNSTONE C. Efficient Rh(II)-Bin-aphthol Phosphate Catalysts in The Enantioselective Intramolecular Tande-m Carbonyl Ylide Formation-Cycloaddition ofα-Diazo-β-Keto Esters[J]. Chemical Communications, 1999, (21): 2185-2186.
[81] KITAGAKI S, ANADA M, KATAOKA O, et al. Enantiocontrol in Tand-em Carbonyl Ylide Formation and Intermolecular 1, 3-Dipolar Cycloaddi-tion ofα-Diazo Ketones Mediated by Chiral Dirhodium (II) Carboxylate Catalyst[J]. Journal of American Chemical Society, 1999, 121(6): 1417- 1418.
[82] SAITO T, YAMADA T, MIYAZAKI S, et al. Evaluation of Chiral Bide-ntate Ligand–Metal Complexes in Asymmetric 1,3-Dipolar Cycloaddition Reaction of Nitrones with 3-Alkenoyl-2-Oxazolidinones[J]. Tetahedron Le-tters, 2004, 45(52): 9581-9584.
[83] SAITO T, YAMADA T, MIYAZAKI S, et al. Catalytic Highly Enantiose-lective 1,3-Dipolar Cycloaddition Reaction of Nitrones with 3-Alkenoyl-2-Oxazolidinones by Use of a Bidentate Chiral Bis(imine) Ligand-Cu(II) T-riflate Complex[J]. Tetahedron Letters, 2004, 45(52): 9585-9587.
[84] PALOMO C, OIARBIDE M, ARCEO E, et al. Lewis Acid Catalyzed Asymmetric Cycloadditions of Nitrones:α'-Hydroxy Enones as Efficient Reaction Partners[J]. Angewandte Chemie International Edition, 2005, 44(38): 6187-6190.
[85] SIBI M P, MA Z, JASPERSE C P, et al. Exo Selective EnantioselectiveNitrone Cycloadditions[J]. Journal of American Chemical Society, 2004, 126(3): 718-719.
[86] SIBI M P, MA Z, ITOH K, et al. Enantioselective Cycloadditions withα,β-Disubstituted Acrylimides[J]. Organic Letters, 2005, 7(12): 2349-2352.
[87] SINGH N K, AGRAWAL M S, AGRAWAL R C. Synthesis,Structure an-d Antifungal Studies of Some 3d Metal Complexes of Salicylaldehrde-2-Furanthio- Carboxyhrdraone[J]. Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry, 1985, 15(1): 75-92.
[88]叶勇,胡继明,曾云鹦.三种席夫碱化合物对DNA作用的表面增强拉曼光谱研究[J].光散射学报,1999,11(3):190-193.
[89]陈春华,陆茜.L-半胱氨酸席夫碱及其铜、锌配合物的合成及表征[J].湖北化工,1998,(5):18-19.
[90] WANG M Z, MENG Z X, LIU B L, et al. Novel Tumor Chemotherap-eutic Agents and Tumor Radioimaging Agents: Potential Tumor Pharmac-euticals of Ternary Copper(II) Complexes[J]. Inorganic Chemistry Comm-unications, 2005, 8(4): 368-371.
[91] MICHACL R, WAGNER F, WALKER A, et al. Spectro Scopic of 1:1 Copper(II) Complexes with Schiff Base Ligands Derived from Salicylabl-ehrde and L-Histidine and Its Analogues[J]. Inorganic Chemistry, 1983, 22(21): 3021-3028.
[92]严振寰,吴自慎,桂自其.4-羟基水杨醛丙氨酸合锌(II)的合成、表征及其抗癌活性的初步研究[J].华中师范大学学报(自然科学版),1989,23(4): 528-532.
[93]王忠,吴自慎,严振寰.2-氯苯甲醛甘氨酸席夫碱及其Cu(II)、Zn(II)、Co(II)、Ni(II)配合物的合成、表征及抗菌活性的研究[J].华中师范大学学报(自然科学版),1993,27(3):334-338.
[94]席晓岚,黎植昌.4-硝基苯甲醛甘氨酸Schiff碱的合成、表征及抑菌活性[J].西南师范大学学报(自然科学版),1999,24(1):46-49.
[95]贤景春,曹高娃,刘宗瑞.含N、O和S的Schiff碱配体与铜(II)、锌(II)配合物的合成及红外光谱研究[J].光谱实验室,1999,16(3):265-267.
[96]贤景春,曹高娃,哈日巴拉.新型Schiff碱配体的合成及其生物活性的研究[J].内蒙古民族师院学报(自然科学版),1999,14(2):145-147.
[97] GUZOW K, MILEWSKA M. 3-[2-(8-Quinolinyl)Benzoxazol-5-yl]Alanine Derivative-A Specific Fluorophore for Transition and Rare-Earth Metal I-on Detection[J]. Tetahedron, 2004, 60(51): 11889-11894.
[98] GARC P Z, YAZIGI V D, LATORRE R O, et al. Electronic Properties of Mixed Valence Iron (II,III) Dinuclear Complexes with Carboxylate Br-idges[J]. Polyhedron, 2006, (25): 2026-2032.
[99] CABEZA N A, CARRETERO M N, PESSOA J C. Preparation and Cha-racterisation of Oxovanadium(IV) Complexes Derived from 6-Diformyl-4-Methyl- Phenol and L-His and L-Ala. Spectroscopic Study of The Syste-m VIV O2++BDF-His[J]. Inorganica Chimica Acta, 2005, 358(7): 2246- 2254.
[100] SOLOSHONOK V A, CAI C Z, HRUBY V J. Asymmetric Michael Ad-dition Reactions of Chiral Ni(II) Complex of Glycine with (N-Trans-Eno-yl)Oxazolidines: Improved Reactivity and Stereochemical Outcome[J]. Tet-rahedron: Asymmetry, 1999, 10(22): 4265-4269.
[101] SOLOSHONOK V A, CAI C Z, HRUBY V J, et al. Stereochemically Defined C-Substituted Glutamic Acids and Their Derivatives. 1. An Effi-cient Asy-mmetric Synthesis of (2S,3S)-3-Methyl- and 3-Trifluoro Methyl-pyroglutamic Acids[J]. Tetahedron, 1999, 55(41): 12031-12044.
[102] SOLOSHONOK V A, CAI C Z, HRUBY V J, et al. Asymmetric Synth-esis of Novel Highly Sterically Constrained (2S,3S)-3-Methyl-3-Trifluoro-methyl- and (2S,3S,4R)-3-Trifluoromethyl-4-Methylpyroglutamic Acids [J].Tetahedron,1999, 55(41): 12045-12058.
[103] SOLOSHONOK V A, CAI C Z, HRUBY V J. A Unique Case of Face Diastereoselectivity in The Michael Addition Reactions between Ni(II)-C-omplexes of Glyal 3-(E-Enoyl)-1,3-Oxazolidin-2-Ones[J]. Tetahedron Lett-ers, 2000, 41(49): 9645-9649.
[104] OLIVEIRA P, RAMOS A M, FONSECA I, et al. Oxidation of LimoneneOver Carbon Anchored Transition Metal Schiff Base Complexes: Effect of The Linking Agent[J]. Catalysis Today, 2005, 102-103: 67-77.
[105] GULLOTTI M, SANTAGOSTINI L, PAGLIARIN R, et al. Synthesis andCharacterization of New Chiral Octadentate Nitrogen Ligands and RelatedCopper(II) Complexes As Catalysts for Stereoselective Oxidation of Cate-hol[J]. Journal of Molecular Catalysis A: Chemical, 2005, 235(1-2): 271-284.
[106] MONZANI E, LINATI L, CASELLA L, et al. Synthesis, Characterizationand Stereoselective Catalytic Oxidations of Chelated Deuterohaem In- Gl-ycyl-L-Histidine Complexes[J]. Inorganica Chimica Acta, 1998, 273(1-2): 339-345.
[107] LIU X W, TANG N, CHANG Y H, et al. The Asymmetric Induction a-nd Catalytic Activity of New Chiral Mn(III)-Schiff-Base Complexes withL-Amino Acids As Steric Groups[J]. Tetrahedron: Asymmetry, 2004, 15(8): 1269-1273.
[108] ANDO R, INDEN H, SUGINO M, et al. Spectroscopic Characterization of Amino Acid and Amino Acid Ester–Schiff-Base Complexes of Oxova-nadium and Their Catalysis in Sulfide Oxidation[J]. Inorganica Chimica Acta, 2004, 357(5): 1337-1344.
[109] SAGHIYAN A S, DADAYAN S A, PETROSYAN S G, et al. New Chir-al NiII Complexes of Schiff's Bases of Glycine and Alanine for Efficient Asymmetric Synthesis ofα-Amino Acids[J]. Tetrahedron: Asymmetry, 2006, 17(3): 455-467.
[110] TAYLOR M S, ZALATAN D N, LERCHNER A M, et al. Highly Enan-tioselective Conjugate Additions toα,β-Unsaturated Ketones Catalyzed byA (Salen) Al Complex[J]. Journal of American Chemical Society, 2005, 127(4): 1313-1317.
[111] RUCK R T, JACOBSEN E N. Asymmetric Catalysis of Hetero-Ene Rea-ctions with Tridentate Schiff Base Chromium (III) Complexes[J]. Journal of the American Chemical Society, 2002, 124(12): 2882-2883.
[112] BELOKON Y N, BULYCHEV A G, MALEEV V I, et al.Asymmetric Synthesis of Cyanohydrins Catalysed by A Potassium-Bis [N-Salicylidene-(R)-Tryptophanato] Cobaltate Complex[J]. Mendeleev Communications, 2004, 14(6): 249-250.
[113] HUTSON G E, DAVE A H, RAWAL V H, et al. Highly Enantioselecti-ve Carbonyl-Ene Reactions Catalyzed by A Hindered Silyl-Salen-Cobalt Complex[J]. Organic Letters, 2007, 9(20): 3869-3872.
[114] WANG S X, WANG M X, WANG D X, et al. Chiral Salen-Aluminum Complex As A Catalyst for Enantioselectiveα-Addition of Isocyanides toAldehydes: Asymmetric Synthesis of 2-(1-Hydroxyalkyl)-5-Aminooxazoles[J]. Organic Letters, 2007, 9(18): 3815-3818.
[115] HANDA S, GNANADESIKAN V, MATSUNAGA S, et al. Syn-SelectiveCatalytic Asymmetric Nitro-Mannich Reactions Using a Heterobimetallic Cu-Sm-Schiff Base Complex[J]. Journal of the American Chemical Socie-ty, 2007, 129(16): 4900-4901.
[116] ARMAREGO W F L. Purification of Laboratory Chemicals[M]. 4th ed. UK: Butterworth-Heinemann Press, 1997: 1-3461.
[117] RASO A G, FIOL J J, ZAFRA A L, et al. Synthesis of Zn N-Salicylid-ene-L-Aminoacidatos: X-Ray Structure of [(N-Salicylidene-L-Alaninato)(A-qua)Zinc(II)]·0.25H2O and [(N-Salicylidene-L-Valinato)(Aqua)Zinc(II)][J]. Polyhedron, 2000, 19(6): 673-680.
[118]李冬成,姚克敏,曹美华.稀土元素与3,4-二羟基苯甲醛缩邻氨基苯甲酸配合物的合成和表征[J].应用化学,1993,10(3):8-11.