One‐Step Synthesis of Pd/HAP Precatalyst for 1,5‐Palladium Migration and C–H Silylation

Developing heterogeneous catalysts via operationally simple and sustainable routes, while maintaining high activity in C–H activation, remains challenging. The one‐step, fully aqueous route affords a hydroxyapatite‐supported palladium precatalyst (Pd/HAP precatalyst) under ambient air without hazardous reagents, organic solvents, or external reductants. The Pd/HAP precatalyst efficiently promotes both 1,5‐palladium migration and C–H silylation with excellent performance across a broad substrate scope. Notably, Pd/HAP achieves a turnover number (TON) of up to 5.3 × 10 4 in the 1,5‐palladium migration, more than a 3100‐fold higher than previously reported values. Our study reveals that hydroxyapatite can effectively inhibit the aggregation of palladium nanoparticles (PdNPs) at elevated temperatures, thereby leading to superior catalytic performance compared to the homogeneous system. Additionally, to the best of our knowledge, this work demonstrates the first example of C–H silylation in which aryl chlorides can serve as competent substrates, albeit with limitations. The Pd/HAP precatalyst is air‐stable for 3 months and reused for 10 consecutive cycles with negligible loss in activity. Mechanistic studies reveal that Pd(II) species on HAP are reduced in situ to Pd(0) and suggest “cocktail”‐type catalysis involving both supported and dissolved Pd species.