Vo Duy-Viet, Wu Tongtong, Luo Yanshu, Xia Yuanzhi, Lee Daesung
Department of Chemistry, University of Illinois Chicago, 845 W. Taylor St., Chicago, Illinois 60607, United States.
College of Chemistry and Materials Engineering, Wenzhou University, 325035 Wenzhou, Zhejiang Province, P. R. China.
Org Lett. 2024 Sep 20;26(37):7778-7782. doi: 10.1021/acs.orglett.4c01649. Epub 2024 Aug 12.
1,3-Diynyl propiolates undergo the Alder-ene reaction to generate enyne-allenes, which participate in the Diels-Alder reaction to provide products of a formal [2 + 2 + 2] cycloaromatization of three alkynes. Without an external alkyne, enyne-allene reacts with one of the alkyne moieties of 1,3-diynyl propiolate, whereas external alkynes can be used to trap enyne-allene to provide various arene products. The substituents on the dienophilic alkynes have a profound impact on their reactivity. In this Diels-Alder reaction, 1,3-diynes display higher reactivity than monoynes; thus, an excess amount (4-5 equiv) of external monoynes needs to be employed to get good product selectivity.
丙炔酸1,3 - 二炔酯发生Alder-ene反应生成烯炔联烯，烯炔联烯参与Diels-Alder反应，以提供三个炔烃进行形式上的[2 + 2 + 2]环芳构化的产物。在没有外部炔烃的情况下，烯炔联烯与丙炔酸1,3 - 二炔酯的一个炔基部分反应，而外部炔烃可用于捕获烯炔联烯以提供各种芳烃产物。亲烯炔烃上的取代基对其反应活性有深远影响。在该Diels-Alder反应中，1,3 - 二炔比单炔具有更高的反应活性；因此，需要使用过量（4 - 5当量）的外部单炔以获得良好的产物选择性。
