Tunable Synthesis of 3-Hydroxylisoquinolin-1,4-dione and Isoquinolin-1-one Enabled by Copper-Catalyzed Radical 6-<i>endo</i> Aza-cyclization of 2-Alkynylbenzamide

Abstract

In this work, switchable synthesis of isoquinolin-1-one and 3-hydroxylisoquinolin-1,4-dione from 2-alkynylbenzamide is reported. The transformation works well with good yields and a broad reaction scope. The synthetic switch for providing isoquinolin-1-one and 3-hydroxylisoquinolin-1,4-dione is enabled by the use of a N₂ or O₂ atmosphere. Mechanism studies show that the reaction proceeds in a regioselective manner via a N-center radical 6-<i>endo</i>-<i>dig</i> aza-cyclization pathway.