| 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 TiCl2-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(CH3COO)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-TiCl2 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. PhCH3 and CH2Cl2 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.
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