Luo Yanshu, Zhang Maosheng, Xia Yuanzhi
College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China.
Chem Commun (Camb). 2024 Oct 29;60(87):12770-12773. doi: 10.1039/d4cc03733b.
Density functional theory calculations uncovered a new mechanism for the rhodium-catalyzed decarbonylative annulation of isatoic anhydride with alkynes, in which the acyloxy group formed from the N-H deprotonation and C-O bond cleavage of isatoic anhydride acts as the directing group to assist the C-H activation. From the generated five-membered rhodacycle intermediate, the final aminoisocoumarin product could be formed by subsequent steps of alkyne insertion, reductive elimination, decarbonylation, and protonation. The isocyanate moiety contained in the annulation intermediate was uncovered as a novel internal oxidant for the reaction, which oxidizes the Rh(I) to Rh(III) by decarbonylation.
密度泛函理论计算揭示了铑催化异吲哚酮酸酐与炔烃脱羰环化反应的一种新机制，其中异吲哚酮酸酐的N-H去质子化和C-O键断裂形成的酰氧基作为导向基团协助C-H活化。从生成的五元铑杂环中间体出发，通过炔烃插入、还原消除、脱羰和质子化等后续步骤可形成最终的氨基异香豆素产物。环化中间体中含有的异氰酸酯部分被发现是该反应的一种新型内氧化剂，它通过脱羰将Rh(I)氧化为Rh(III)。
