Solvent‐Free Ruthenium‐Catalyzed Direct Coupling of Phosphines and Aryl Chlorides via C−H Activation: An Efficient and Straight Access to Aryl‐Substituted Biarylphosphines

Abstract An efficient and straightforward synthesis of aryl‐substituted biarylphosphines via unprotected amino acid‐accelerated ruthenium‐catalyzed P‐directed ortho ‐C−H arylation reaction is described. This protocol utilized commercial and inexpensive (hetero)aryl chlorides as efficient arylating reagents under solvent‐free reaction conditions. Notably, diverse aryl bromides were also effective for this transformation. With the protocol, a wide variety of mono‐arylated biarylphosphines were obtained in moderate to high yields and excellent selectivity. Moreover, the aryl‐substituted phosphine exhibited higher catalytic performance than its precursor and other substituted phosphines in palladium‐catalyzed Suzuki coupling.