Insertion of Alkenes into Aryl Nitrile C–C Bonds Enabled by Thiophenolate Photocatalysis

Insertion of alkenes into chemical bonds represents a powerful strategy for carbon framework editing, yet direct insertion into C–C bonds remains a formidable challenge due to the nonpolarity, high-lying σ* orbital, steric shielding, and high thermodynamic stability of the C–C bond. Here, we present a visible-light-driven thiophenolate photocatalytic system that enables direct insertion of alkenes into the C–C bond of aryl nitriles. Mechanistic studies reveal a photoinduced single-electron transfer from the excited thiophenolate anion to the aryl nitrile, generating a radical pair that undergoes radical addition and radical–radical cross-coupling, followed by elimination and nucleophilic addition to afford the insertion product. This strategy not only provides an avenue for editing inert C–C bonds but also establishes thiophenolate photocatalysis as a platform for challenging bond constructions under transition-metal-free and redox-neutral conditions.