Lanthanide triflate catalyzed imino Diels-Alder reactions of imines with dienes or alkenes have been developed. A new group of Lewis acids, lanthanide triflates, are quite effective for the catalytic activation of imines. Unique reactivities of imines which work as both dienophiles and azadienes under certain conditions have been revealed. Three-component coupling reactions between aldehydes, amines, and dienes or alkenes were successfully carried out by using lanthanide triflate as a catalyst to afford pyridine and quinoline derivatives in high yields. The Lewis acid catalysts were stable and kept their activity even in the presence of water and amines. A stepwise reaction mechanism for these reactions is suggested from the experimental results.
已开发了
铈三氟甲磺酸盐催化的
亚胺与二烯或烯烃的
亚胺Diels-Alder反应。新一类
路易斯酸,即
铈三氟甲磺酸盐,在催化
亚胺的活化方面非常有效。已揭示出
亚胺在某些条件下同时作为二烯亲和体和氮烯体的独特反应性。通过使用
铈三氟甲磺酸盐作为催化剂,成功进行了醛、胺与二烯或烯烃之间的三组分偶联反应,得到高产率的
吡啶和
喹啉衍
生物。这些
路易斯酸催化剂在
水和胺存在的情况下依然保持稳定性和活性。根据实验结果,提出了这些反应的逐步反应机理。