Mechanisms of Metal-Catalyzed Hydrophosphination of Alkenes and Alkynes

The elementary steps in proposed mechanisms for the hydrophosphination of alkenes or alkynes catalyzed by metal complexes are examined carefully with respect to the various potential roles of the metal center. This provides a context for understanding the unusually wide breadth of unsaturated substrates that participate in a P-C bond forming process mediated by a half-sandwich ruthenium system.