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Cu(I)催化的炔烃与叠氮的Huisgen 1,3-偶极环加成反应(CuAAC)可用于构建三唑环,该反应条件温和,产物专一,被认为是“点击化学”的精髓,并广泛应用于医药、生物有机及材料化学等多个领域.CuSO_4/抗坏血酸钠体系是该反应最常用的催化方法,但近年来,大量更高效的催化体系被成功开发以解决当前催化体系中存在的问题,例如,外加配体的使用可以明显加快反应速率,从而降低催化剂用量和缩短反应时间,这归因于配体参与配位可以更好地稳定Cu(I)催化中心.目前应用于该反应体系的配体大多为对称型多齿氮配体,例如三三唑甲胺衍生物(TBTA)等.我们开发了两类含有吡唑、苯并咪唑等基团的非对称型多齿氮配体及其应用,发现这类配体除了具有稳定金属中心的作用外,还因有吡唑或苯并咪唑等基团的存在,所形成的配合物往往比那些包含对称型配体的配合物表现出更高的催化活性.本文合成了一类含有非对称型配体的铜配合物.将铜前体Cu(CH_3CN)_4PF_6与非对称型多齿氮配体二吡啶甲基吡唑甲基胺(HNpy2pz)在甲醇中反应,由于配体结构中吡唑NH基团的存在,反应在最终脱除一分子H_2O后,意外获得了一种双核结构的铜配合物,其分子结构通过X射线单晶衍射成功表征.受到两个金属中心协同效应的影响,双核配合物催化剂往往能表现出比单核配合物更优异的催化性能,因此,我们进一步考察了该双核配合物催化CuAAC反应的活性.结果表明,在催化剂用量低至0.1 0.3 mol%的情况下,22种炔烃和叠氮在25 oC反应16 h均能得到单一的1,4-二取代三唑产物,分离收率在95%以上,且抗坏血酸钠还原剂用量仅需1 3 mol%,说明受到配体的影响,催化剂的稳定性非常好.这是目前该反应成功开发出的几个高效双核催化剂之一.
The Cu (I) -catalyzed Huisgen 1,3-dipolar cycloaddition reaction (CuAAC) of alkyne with azide can be used to construct the triazole ring. The reaction conditions are mild and product specific and are considered as “click chemistry” "And is widely used in many fields such as medicine, bio-organic and material chemistry, etc. CuSO_4 / sodium ascorbate system is the most commonly used catalytic method in this reaction, but in recent years, a large number of more efficient catalytic systems have been successfully developed to solve the current The problems in the catalytic system, for example, the use of additional ligands can significantly speed up the reaction rate, thereby reducing the amount of catalyst and shortening the reaction time, which is attributed to the better coordination of the ligand to the Cu (I) catalytic center. At present, most of the ligands used in this reaction system are symmetric polydentate nitrogen ligands such as trimetazolamide derivative (TBTA), etc. We have developed two types of asymmetric pyrazole, benzimidazole and other groups Type polydentate nitrogen ligands and their applications, found that such ligand in addition to stabilizing the role of the metal center, but also due to the presence of pyrazole or benzimidazole groups, the formation of the complexes tend to contain more than those containing symmetry Ligand complexes show higher urination In this paper, we synthesized a series of Cu (CH 3 CN) 4PF 6 complexes with asymmetric polypyridyl ligand bipyridine methylpyrazole methylamine (HNpy 2pz) in methanol Due to the existence of pyrazole NH group in the ligand structure, a dinuclear copper complex was unexpectedly obtained after the reaction was finally removed. The molecular structure was successfully characterized by X-ray single crystal diffraction. Due to the synergetic effect of the two metal centers, the binuclear complex catalyst can show more excellent catalytic performance than the mononuclear complex, so we further investigated the activity of the binuclear complex catalyzed CuAAC reaction.The results show that in the catalyst With the dosage as low as 0.1 0.3 mol%, a single 1,4-disubstituted triazole product was obtained with 22 alkyne and azide reacted at 25 oC for 16 h, and the yield was above 95%, and sodium ascorbate The amount of the reducing agent only needs 13 mol%, indicating that the stability of the catalyst is very good due to the influence of the ligand, which is one of several highly efficient binuclear catalysts successfully developed by the reaction.