One‐Pot Cascade Synthesis of Isoquinolinone‐Fused Quinoxalines Through Sequential Rh(III)/Pd(II) Catalysis

A sequential bimetallic Rh(III)/Pd(II)‐catalyzed reaction of N ‐(2‐acetamidophenyl)benzamides with 1,3‐diynes via an NH/CH activation and cyclization cascade is reported. The one‐pot synthesis of isoquinolinone‐fused quinoxalines is achieved through dual‐metal catalysis. The reaction proceeds via Rh(III)‐catalyzed, amide‐group‐directed CH activation and migratory insertion of 1,3‐diyne, followed by cyclization to form an isoquinolinone intermediate. Subsequent Pd(II)‐catalyzed aminopalladation, intramolecular migratory insertion of the CC triple bond into the CPd bond, and protodemetalation furnish the isoquinolinone‐fused quinoxaline frameworks.