负载型双噁唑啉催化剂上的不对称Diels-Alder反应

 分别以乙烷桥键磺酸官能化的有机-无机杂化介孔材料、十二钨磷酸铯、活化硅胶以及SBA-15为载体,通过非共价键作用制备了负载型双噁唑啉催化剂,并将该催化剂用于催化3-((E)-2-丁烯酰基)-1,3-噁唑啉-2-酮和环戊二烯的不对称Diels-Alder反应. 研究表明,催化剂的性能取决于载体本身以及载体表面阴离子的性质. 以SBA-15为载体时产物的对映体选择性较低,可归因于载体表面较低的羟基浓度.

Asymmetric Diels-Alder Reactions on Supported Bis(Oxazoline) Catalysts

Periodic mesoporous ethane-silicas functionalized with sulfonic acid, cesium salts of 12-tungstophosphoric acid, activated silica, and SBA-15 have been used as solid supports for the immobilization of the bis(oxazoline) copper (II) catalyst via non-covalent interactions. These heterogeneous catalysts have been evaluated for the Diels-Alder reaction between 3-((E)-2-butenoyl)-1,3-oxazolin-2- one and cyclopentadiene. The performance of the catalyst relies on the nature of both the support and the anion on the surface of the support. The small number of the silanol groups on the support leads to poor enantioselectivity when SBA-15 is used.