Design of Benzimidazolyl Phosphines Bearing Alterable P,O or P,N‑Coordination: Synthesis, Characterization, and Insights into Their Reactivity

A new series of hemilabile benzimidazolyl phosphines is reported. Entities in this ligand family can be easily assembled and prepared on a large scale via a simple one-pot procedure. X-ray crystallographic analyses show that the Pd metal center can coordinate in different fashions, where it relies on the size of the −PR2 group. With the same ligand scaffold, the ligand having a −PCy2 moiety displays better efficiency in expediting aromatic C–C bond-coupling reactions, while the ligand associated with a −P-t-Bu2 group, in contrast, promotes C–N bond-forming reactions.