Scandium triflate and secondary amine promoted AA′B 2:1 coupling and formal inverse electron demand Diels–Alder reactions of dienals
作者:Chris D. Smith、Robert A. Batey
DOI:10.1016/j.tet.2007.11.035
日期:2008.1
ion activation of the diene. A purely amine promoted formal inverse electron demand Diels–Alder cycloaddition approach was also demonstrated in the 2:1 coupling of 2,4-hexadienal with methanol. These reactions demonstrate the concepts of dual metal/amine catalysis and amine promoted formal inverse electron demand Diels–Alder cycloadditions. They differ from known examples of organocatalyzed Diels–Alder
反应前瞻性研究导致发现Sc(OTf)3促进了咪唑酮或苯并呋喃取代的烯醛与吗啉的新型AA'B 2:1偶联。相关的Sc(OTf)3证明了吗啉促进的反应用于苯并呋喃取代的烯醛与二氢呋喃的偶联。这些加合物的形成与形式上的逆电子需求Diels-Alder环加成相一致,最有可能通过逐步发生的多米诺米歇尔-曼尼希(Domino Michael-Mannich)环化过程,涉及二烯的亚胺离子活化。在2,4-己二醛与甲醇的2:1偶联中也证明了纯胺促进了形式逆电子需求的Diels-Alder环加成反应。这些反应证明了双重金属/胺催化的概念,并且胺促进了形式逆电子需求Diels–Alder环加成反应。它们与已知的有机催化Diels-Alder反应的例子不同,在Diels-Alder反应中,二烯亲和物的亚胺离子活化或二烯的烯胺活化。