Mild Reduction of Phosphine Oxides with Phosphites To Access Phosphines.

A new method for the iodine-catalyzed reduction of phosphine oxides with phosphites at room temperature is reported. The mild reaction conditions, scalability, and simple purification requirements render it a method of choice for the large-scale production and facile regeneration of a variety of phosphines. Mechanistic studies, supported by DFT calculations of the oxygen transfer between the starting phosphine oxide and the phosphite reagent, are also presented. Such transmutations of phosphorus species were previously unknown.