手性脱氢枞胺希夫碱铜配合物催化不对称Henry反应的研究
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摘要
合成了基于松香衍生物脱氢枞胺的光学纯手性希夫碱配体N-(2-亚甲基吡啶)脱氢枞胺(L)的铜配合物,以及铜配合物[Cu(L)2Cl]Cl(1)和[Cu(L)2Br]Br(2).研究了铜配合物催化苯甲醛和硝基甲烷的不对称Henry反应的活性,考察了金属盐的种类、配体/金属比例、溶剂、反应温度和时间及外加碱等条件对反应的影响.实验结果表明:在无须除氧和除湿的温和条件下,即时生成的CuCl2-L配合物作为催化剂的反应产率和选择性较高,配合物1和2没有催化活性.
The catalytic efficiency of in situ generated copper(Ⅱ)complexes of rosin-based chiral Schiff-base N-[(pyridin-2-ylmethylene)-imino]dehydroabietylamine)(L)and pre-prepared copper complexes[Cu(L)2 Cl]Cl(1)and[Cu(L)2 Br]Br(2)was estimated in the asymmetric Henry reaction of benzaldehyde and nitromethane.The effect of metal salts type,ligand/metal ratio,solvent,reaction temperature and time and base additive on the reaction were studied.The optimal catalyst was the in situ generated CuCl2-L in terms of yield and enantioselectivity under mild experimental conditions without air or moisture exclusion,however,complexes 1 and2 were found to be ineffective.The results suggest it is deserved to explore rosin derivatives in asymmetric catalysis field.
The catalytic efficiency of in situ generated copper(Ⅱ)complexes of rosin-based chiral Schiff-base N-[(pyridin-2-ylmethylene)-imino]dehydroabietylamine)(L)and pre-prepared copper complexes[Cu(L)2 Cl]Cl(1)and[Cu(L)2 Br]Br(2)was estimated in the asymmetric Henry reaction of benzaldehyde and nitromethane.The effect of metal salts type,ligand/metal ratio,solvent,reaction temperature and time and base additive on the reaction were studied.The optimal catalyst was the in situ generated CuCl2-L in terms of yield and enantioselectivity under mild experimental conditions without air or moisture exclusion,however,complexes 1 and2 were found to be ineffective.The results suggest it is deserved to explore rosin derivatives in asymmetric catalysis field.
引文
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[2] SOLINAS M,SECHI B,BALDINO S,et al.Synthesis and application of new iminopyridine ligands toenantioselective copper(Ⅱ)-catalyzed Henry reaction[J].J Mol Catal A-Chem,2013,378:206-212.
[3] MANIKANDAN R,ANITHA P,PRAKASH G,et al.Synthesis,spectral characterization and crystal structure of Ni(Ⅱ)pyridoxal thiosemicarbazone complexes and their recyclable catalytic application in the nitroaldol(Henry)reaction in ionic liquid media[J].Polyhedron,2014,81:619-627.
[4] SUTRADHAR M,SILVA M F C G,POMBEIRO A J L.A new cyclic binuclear Ni(Ⅱ)complex as a catalyst towards nitroaldol(Henry)reaction[J].Catal Commun,2014,57:103-106.
[5] DAS A,KURESHY R I,SUBRAMANIAN P S,et al.Synthesis and characterization of chiral recyclable dimeric copper(Ⅱ)-salen complexes and their catalytic application in asymmetric nitroaldol(Henry)reaction[J].Catal Sci Technol,2014,4(2):411-418.
[6] GAN C,LAI G,ZHANG Z,et al.Efficient and enantioselective nitroaldol reaction catalyzed by copper Schiff-base complexes[J].Tetrahedron:Asymmetr 2006;17(2):725-728.
[7] JIANG X,ZHANG Y,LIU X,et al.Enantio-and diastereoselective asymmetric addition of 1,3-dicarbonyl compounds to nitroalkenes in a doubly stereocontrolled manner catalyzed by bifunctional rosin-derived amine thiourea catalysts[J].J Org Chem,2009,74(15):5562-5567.
[8] FEI B L,LI W,XU W S,et al.Synthesis,crystal structure,DNA binding,antibacterial and cytotoxic activities of two chiral copper(Ⅱ)complexes[J].Eur J Inorg Chem,2013,(34):5919-5927.
[9] SEMA H A,BEZA G,KARMAKARB S.Asymmetric Henry reaction catalysed by L-proline derivatives in the presence of Cu(OAc)2:isolation and characterization of an in situ formed Cu(Ⅱ)complex[J].Appl Organomet Chem,2014,28(4):290-297.
[10] GAN C,LAI G,ZHANG Z,et al.Efficient and enantioselective nitroaldol reaction catalyzed by copper Schiff-base complexes[J].Tetrahedron:Asymmetry,2006,17(5):725-728.
[11] NGUYEN Q T,JEONG J H.Synthesis and X-ray structure of a Cu(Ⅱ)complex of N,N′-bis(2-pyridylmethylidene)-(R,R)-1,2-diaminocyclohexane and its catalytic application for asymmetric Henry reaction[J].Polyhedron,2006,25(8):1787-1790.
[12] PURKARTHOFER T,GRUBER K,GRUBER-KHADJAWI M,et al.A biocatalytic Henry reaction-the hydroxynitrile lyase from hevea brasiliensis also catalyzes nitroaldol reactions[J].Angew Chem Int Edit,2006,45(21):3454-3456.
[13] WE Y,YAO L,ZHANG B,et al.Novel Schiff base ligands derived from cinchona alkaloids for Cu(Ⅱ)-catalyzed asymmetric Henry reaction[J].Tetrahedron,2011,67(44):8552-8558.