Photo-induced tungsten-catalyzed cascade synthesis of pyrrolo[2,1- < em > a < /em > ]isoquinoline-1,3-dicarboxylate and its reaction mechanism

This article describes a tungsten-catalyzed [3+2] cycloaddition aromatization of dihydroisoquinoline ester and maleic anhydride or an acrylate. The photochemical reaction tolerates a range of functional groups such as ester, cyano, ketone, bromide, and alkene. It is shown that the cycloaddition-aromatization of 2-substitued acrylate catalyzed by a tungsten photocatalyst can be used to evaluate the leaving ability of the leaving group. Experiments done to determine the reaction mechanism revealed that the formation of an ion-pair intermediate generated in situ from dihydroisoquinoline ester and (Z)-4-methoxy-4-oxobut-2-enoic acid via the solvolysis of maleic anhydride with methanol is crucial for the cascade process to occur. The key cycloadduct acid intermediate derived from [3+2] cycloaddition was isolated and determined by X-ray crystallography.PMID:38572995 | DOI:10.1039/d4cc00169a

Source: Chemical Communications - April 4, 2024 Category: Chemistry Authors: Yongshun Wen Hong-Xian Jin Yan-Hua Qiu Yingtong Zong Wenjun Luo Zhengwang Chen Daohong Yu Source Type: research