Fast Suzuki–Miyaura Cross‐Coupling Reaction with Hexacationic Triarylphosphine Bn‐<i>Dendriphos</i> as Ligand

Abstract

Abstract The application of hexa[(dimethylamino)methyl]‐functionalized triphenylphosphine ( 1 ) and its benzylammonium salt, Bn‐ Dendriphos ( 2 ), in the Suzuki–Miyaura cross‐coupling of aryl bromides with arylboronic acids is described. The 3,5‐bis[(benzyldimethylammonio)methyl] substitution pattern in 2 leads to a rate enhancement compared to both the non‐ionic parent compound 1 and triphenylphospine (PPh 3 ) itself. At the same time, the resulting catalytic species are stable towards palladium black formation, even at a phosphine/palladium ratio of 1. These observations are attributed to the presence of a total of six ammonium groups in the backbone of the phosphine ligand, which presumably leads to an unsaturated phosphine‐palladium complex.