Phosphines are widely used ligands in transition metal-catalyzed reactions.
Arylphosphines, such as triphenylphosphine, were among the first phosphines to show
broad utility in catalysis. Beginning in the late 1990s, sterically demanding and electronrich
trialkylphosphines began to receive attention as supporting ligands. These ligands
were found to be particularly effective at promoting oxidative addition in cross-coupling
of aryl halides. With electron-rich, sterically demanding ligands, such as tri-tertbutylphosphine,
coupling of aryl bromides could be achieved at room temperature. More
importantly, the less reactive, but more broadly available, aryl chlorides became accessible
substrates. Tri-tert-butylphosphine has become a privileged ligand that has found application
in a wide range of late transition-metal catalyzed coupling reactions. This success
has led to the use of numerous monodentate trialkylphosphines in cross-coupling reactions. This review
will discuss the general properties and features of monodentate trialkylphosphines and their application in
cross-coupling reactions of C–X and C–H bonds.
Three-Coordinate Zinc Methyl Complexes with Sterically Demanding Formazanate Ligands
