阳离子稀土化合物催化氢烷氧化和氢硫化反应的研究

The Lewis acidity of cationic rare-earth metal complexes is commonly higher than that of the corresponding neutral complexes. However, application of cationic rare-earth metal complexes as Lewis acid-type catalysts in organic synthesis has been neglected for a long time. Besides, hydroelementation reactions of unsaturated C─C bonds represent an efficient and atom-economical approach for the introduction of heteroelements into carbon-based structures. .Based on our previous work, some cationic rare-earth metal complexes will be synthesized and used as Lewis acid-type catalysts for hydroalkoxylation and hydrothiolation of alkene, alkyne, allene, and conjugated diene. The catalytic activities of these cationic rare-earth metal complexes will be studied and compared with those of the corresponding neutral complexes. The effect of the coordination sphere around the cationic rare-earth metal centers on their Lewis acidity will be investigated, and the differences in mechanism between the hydroelementation processes catalyzed by cationic and neutral rare-earth metal complexes will be discussed. The focus of the project is to understand the relationship between the structure of these cationic rare-earth metal complexes and the activity and selectivity of the reactions. Based on the results obtained from this research, several novel cationic rare-earth metal complexes will be synthesized and used as Lewis acid-type catalysts of high efficiency and high selectivity for hydroalkoxylation and hydrothiolation of C─C unsaturations. At the same time, several highly efficient and selective processes for C─O and C─S bond-forming will be developed.

阳离子稀土化合物通常具有强于相应中性稀土化合物的Lewis酸性。利用这一特性而将阳离子稀土化合物用于催化有机反应方面的研究是一以往较少被关注的领域。另一方面，碳碳重键的氢元素化反应是符合时代需要的高度原子经济性的碳-杂键生成手段。.本项目将在已有探索工作的基础上，合成几类不同配位环境的阳离子型稀土化合物并用于催化氢烷氧化反应和氢硫化反应，系统研究它们的催化活性和选择性，了解催化剂结构对反应活性和选择性的影响规律，比较阳离子稀土化合物与相应的中性稀土化合物作用于这些反应中的机理的差异，开发用于氢烷氧化、氢硫化反应的高效、高选择性稀土催化剂，发展原子经济性生成C─O、C─S键的高活性、高选择性的方法。

阳离子稀土化合物通常具有强于相应中性稀土化合物的Lewis酸性，前者因而比后者更为亲电，从而易于在均相催化中承担活性更高催化剂的角色。然而，利用这一特性而将阳离子稀土化合物用于催化有机反应方面的研究是以往较少被关注的领域。另一方面，碳碳重键的氢烷氧化反应、氢硫化反应是符合时代需要的高度原子经济性的碳-杂键生成手段。.本项目在已有探索工作的基础上，合成了几类不同结构的[稀土-M]离子对化合物，其中主要为阳离子型稀土化合物。以它们为催化剂，本项目考察了一系列氢烷氧化反应和氢硫化反应，其中碳碳重键底物包括活化或未活化的烯、炔、共轭二烯和,-不饱和羰基化合物等，羟基底物包括醇和酚，巯基底物为苯硫酚等。本项目系统研究了它们在反应中的催化活性和选择性，探索了反应机理，了解了催化剂结构对反应活性和选择性的影响规律，发展了一些用于氢烷氧化、氢硫化反应的高效稀土催化体系，发展了一系列合成醚、硫醚、苯并吡喃、萘并大环半缩酮、二氧代二环[3,3,1]壬烷、2-氨基苯并噻嗪等有价值的有机化合物的高活性方法。