NiH-Catalyzed Homobenzylic Hydroalkylation of Aryl Alkenes Using Sulfoxonium Ylides

We present here the first example of NiH-catalyzed homobenzylic hydroalkylation of aryl alkenes mediated by a nickel carbene radical, achieving the elusive β-selectivity with excellent regiocontrol. Mechanistic investigations suggest that this transformation is enabled by the preferential engagement of NiH with bench-stable sulfoxonium ylides, whose unique chelation properties promote carbene activation prior to alkene insertion. The resulting nickel carbene radical is proposed to undergo selective β-addition, followed by intramolecular metal hydride transfer and protodemetalation. The reaction exhibits broad scope across aryl, heteroaryl, and complex bioactive alkene derivatives, as well as diverse sulfoxonium ylides. This work establishes a new mechanistic platform for NiH catalysis, expanding the synthetic repertoire for site-selective alkene functionalization.