Dynamic covalent approach to [2]- and [3]rotaxanes by utilizing a reversible thiol-disulfide interchange reaction
Dynamic covalent approach to [2]- and [3]rotaxanes by utilizing a reversible thiol-disulfide interchange reaction
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DOI：
10.1002/chem.200204644
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发表时间：
2003-06-16
影响因子：
4.3
通讯作者：
Takata, T
中科院分区：
文献类型：
--
作者：
Furusho, Y;Oku, T;Takata, T
描述了一种含二硫化物的[2]-和[3]轮烷的动态共价方法。合成了具有两个仲铵中心和一个中心位置的二硫键的对称哑铃状化合物作为轮烷的组分。以二苯并-[24]冠-8(DB24C8)为原料，苯硫醇为催化剂，合成了哑铃型轮烷化合物。在优化的反应条件下，分离轮烷的产率可达90%左右。对生成[2]轮烷2a和[3]轮烷3a的反应进行了动力学研究，提出了一个合理的反应机理，包括1)引发、2)[2]轮烷生成和3)[3]轮烷生成。整个反应在硫醇存在下是可逆的，因此可以通过改变温度、溶剂、底物初始比例和浓度来对产物分布进行热力学控制。末端封端基团的空间体积对轮烷的产率几乎没有影响，但硫醇的结构对反应速度是至关重要的。胺和膦也是有效的催化剂。轮烷的结构表征包括对[3]轮烷3a的X射线结晶学研究。
A dynamic covalent approach to disulfide-containing [2]- and [3]rotaxanes is described. Symmetrical dumbbell-shaped compounds with two secondary ammonium centers and a central located disulfide bond were synthesized as components of rotaxanes. The rotaxanes were synthesized from the dumbbell-shaped compounds and dibenzo-[24]crown-8 (DB24C8) with catalysis by benzenethiol. The yields of isolated rotaxanes reached about 90% under optimized conditions. A kinetic study on the reaction forming [2]rotaxane 2a and [3]rotaxane 3a suggested a plausible reaction mechanism comprising several steps, including 1) initiation, 2) [2]rotaxane formation, and 3) [3]rotaxane formation. The whole reaction was found to be reversible in the presence of thiols, and thermodynamic control over product distribution was thus possible by varying the temperature, solvent, initial ratio of substrates, and concentration. The steric bulk of the end-capping groups had almost no influence on rotaxane yields, but the structure of the thiol was crucial for reaction rates. Amines and phosphines were also effective as catalysts. The structural characterization of the rotaxanes included an X-ray crystallographic study on [3]rotaxane 3a.