Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States.
J Org Chem. 2017 Jun 16;82(12):6398-6402. doi: 10.1021/acs.joc.7b01132. Epub 2017 Jun 2.
The mechanisms of recently reported Lewis acid-catalyzed Diels-Alder reactions of arylallenes and acrylates were studied using density functional theory calculations. A stepwise mechanism involving short-lived zwitterion intermediates is established. The reaction is endo-selective in the presence of Lewis acid catalyst. The [2 + 2] cycloaddition is not observed because of the greater charge separation in the first step of the [2 + 2] cycloaddition. The origins of chirality transfer in the Diels-Alder reaction using chiral arylallenes are uncovered, and the absolute stereochemistry of the product is predicted.
使用密度泛函理论计算研究了最近报道的芳基丙烯和丙烯酸盐的路易斯酸催化 Diels-Alder 反应的机理。建立了涉及短寿命两性离子中间体的分步机制。在路易斯酸催化剂存在下，反应具有内选择性。由于[2+2]环加成第一步的电荷分离更大，因此未观察到[2+2]环加成。揭示了使用手性芳基丙烯的 Diels-Alder 反应中手性转移的起源，并预测了产物的绝对立体化学。
