Early-Transition-Metal-Mediated Activation and Transformation of White Phosphorus

Phosphorus-containing molecules are ubiquitous in the world around us and the synthetic and industrial utilization of phosphorus has prospered for over a century. The industrial reduction of phosphate rock (apatite, Casubscript 10(POsubscript 4)subscript 6(X)subscript 2, X = OH, F, Cl, or Br) to white phosphorus, Psubscript 4, exceeds 500,000 tons annually as Psubscript 4 still represents the major commercial P-atom source for the production of organophosphorus compounds utilized by the food, detergent, specialty chemical, and pharmaceutical industries. The present day synthesis of organophosphorus compounds is a multi-step process in which Psubscript 4 is first chlorinated to generate PClsubscript 3, which in turn is functionalized by reaction with an appropriate Grignard or organolithium reagent, or by treatment with a halogenated organic compound and a powerful reducing agent. For example, the industrial method for triphenylphosphine preparation is based on the high temperature reaction of chlorobenzene with phosphorus trichloride in the presence of molten sodium. From both a safety and a sustainability standpoint, the need for PClsubscript 3 as an intermediate for the production of organophosphorus compounds is unpalatable and methods that circumvent its use are of great interest. This has provoked intensive investigations into the mild and controlled activation of Psubscript 4, a clear objective being the development of catalytic methods for phosphorus incorporation into organic molecules.