Abstract
Diphenylprolinol silyl ether is a widely used organocatalyst, and its immobilization on a solid support was investigated for the easy recycling and reuse of this catalyst. Because a silyl ether bond of the catalyst is weak, its alkyl ether was attached to polymers such as a polyquinoxaline-based polymer, a polystyrene polymer (PS) resin, and a polystyrene–poly(ethylene glycol) graft copolymer (PS-PEG) resin. Although a polymer-supported organocatalyst generally decreases its reactivity compared with the monomer catalyst, diphenylprolinol anthrylmethyl ether supported on PS-PEG was found to be a reactive organocatalyst; it catalyzed the Michael reaction of an aldehyde and a nitroalkene in water without an organic solvent being present, with excellent diastereo- and enantioselectivities.
摘要
二苯基脯氨醇硅基醚是一种广泛使用的有机催化剂,为了便于这种催化剂的回收和再利用,研究人员对其在固体载体上的固定化进行了研究。由于该催化剂的硅醚键较弱,因此将其烷基醚附着在聚喹喔啉基聚合物、聚苯乙烯聚合物(PS)树脂和聚苯乙烯-聚乙二醇接枝共聚物(PS-PEG)树脂等聚合物上。虽然与单体催化剂相比,聚合物支撑的有机催化剂通常会降低其反应活性,但研究发现,PS-PEG 上支撑的二苯基脯氨醇蒽酰甲基醚是一种活性有机催化剂;它可以催化醛和硝基烯在水中的迈克尔反应,而无需有机溶剂,并具有极佳的非对映和对映选择性。