Highly efficient Suzuki coupling using moderately bulky tolylphosphine ligands

Tolylphosphines, P(o-tolyl)nPh3 − n have been used in the palladium catalyzed Suzuki cross-coupling reactions of a series of aryl-bromides, chlorides and also two bromoarylphosphine oxides and a bromoarylphosphine with arylboronic acids. The effects of the phosphine, palladium source, base, solvent and promoter salt were investigated. In all studied phosphines, particularly P(o-tolyl)2Ph high conversions and turnovers were seen compared to ortho-unsubstituted phosphines which indicates that other factors such as cyclometallation in addition to steric and electronic effects may be responsible.

Tolylphosphines, P(o-tolyl)nPh3 − n promote efficiently the palladium catalyzed Suzuki cross-coupling reaction of arylboronic acids with aryl halides and bromoarylphosphine oxides with high conversions and turnovers. Figure optionsDownload as PowerPoint slide