Efficient Organocatalyst Supported on a Simple Ionic Liquid as a Recoverable System for the Asymmetric Diels-Alder Reaction in the Presence of Water
作者:Antonio De Nino、Loredana Maiuolo、Pedro Merino、Monica Nardi、Antonio Procopio、David Roca-López、Beatrice Russo、Vincenzo Algieri
DOI:10.1002/cctc.201402973
日期:2015.3
investigated. The Diels–Alder reactions of several dienes and dienophiles proceeded efficiently in the presence of the catalyst to provide the desired products in moderate to good yields and from good to excellent enantioselectivities. The conformation study confirms that in the transition state the Re face is shielded completely by the phenyl ring and an approach on the less hindered Si face is preferred. Particularly
新型高效有机催化剂,即(5 S)-2,2,2,3-三甲基-5-硫代苄基甲基-4-咪唑啉酮盐酸盐的合成,表征和评估已经完成。催化剂具有重要的结构特征,应增加催化效率和在极性介质中的溶解度。研究了离子液体负载的咪唑烷酮催化剂在对映选择性Diels-Alder反应中的应用。在催化剂的存在下,几种二烯和亲二烯体的狄尔斯-阿尔德反应有效地进行,以中等至良好的收率和良好的至优异的对映选择性提供了所需的产物。构象研究证实,在过渡状态下,Re表面被苯环完全屏蔽,最好采用受阻较小的Si表面。特别引人注目的是,整个离子液体/ HCl 0.01 M /催化剂体系可以回收并重复使用多达六次,而不会明显降低催化活性。