Synthesis of Novel Bulky, Electron-Rich Propargyl and Azidomethyl Dialkyl Phosphines and Their Use in the Preparation of Pincer Click Ligands

Phosphorus-containing compounds bearing versatile functional groups are particularly attractive as synthetic building blocks, especially if these groups can be easily transformed and further diversified. We have developed a novel and efficient approach to the synthesis of novel dialkyl-substituted propargyl, azidomethyl, bromomethyl, and carboxymethyl phosphines. Importantly, the development of a synthetic route for these unprecedented compounds allowed for facile preparation of new pincer click ligands bearing phosphine donors with bulky electron-donating alkyl substituents. This represents a crucial extension of the recently established triazole-based tridentate ligand family.