Metal‐Free K2S2O8 Mediated Synthesis of 3‐(Substituted)‐2‐Arylisoindolin‐1‐One Derivatives With Cascade C−N/C−C Bond Formations Via Radical Cyclization

Abstract A facile technique was demonstrated for the synthesis of 2‐hydroxy‐2‐[ N ‐(alkyl/aryl/heteroaryl)‐3‐oxoisoindolin‐1‐yl]‐1H‐indene‐1,3(2H)‐diones by using a metal‐ free persulfate‐mediated one pot three‐component reaction. The reaction involved the combination effect of TBAB (PTC) and K 2 S 2 O 8 with the addition of the amine to phthalaldehyde and 2,2‐dihydroxyindane‐1,3‐dione to generate isoindolin‐1‐one in‐situ , followed by cyclization.This lactamization process facilitated the formation of C−N bonds under controllable and ambient reaction conditions. A variety of 2‐hydroxy‐2‐[ N ‐(substituted)‐3‐oxoisoindolin‐1‐yl]‐1H‐indene‐1,3(2H)‐diones were successfully synthesized through a radical pathway from isoindolin‐1‐one, involving C−C bond formation. The method demonstrated high functional group compatibility and a wide substrate scope, resulting in moderate to good yields of the desired products. Additionally, the mechanistic analyses demonstrated that isoindolin‐1‐one might be a significant intermediate being involved in the reaction. X‐ray diffraction analysis was used to examine the crystal structures of synthesized 2‐hydroxy‐2‐[ N ‐(substituted)‐3‐oxoisoindolin‐1‐yl]‐1H‐indene‐1,3(2H)‐diones. Furthermore, it seems that the reaction mechanism involves a radical pathway.