The conversion of oxygen-containing compounds is often achieved by the use of phosphorus reagents. The newly formed phosphine oxide bond delivers the enthalpic gain that drives reactions, such as the Wittig, Mitsunobu, and Appel reaction, to completion. However, phosphine oxides are recognized as undesirable waste products and in the past decade several methods have emerged that address this issue by in situ regeneration of the phosphorus reagent. This Minireview outlines the two distinct strategies and underpinning research that led to these advances. The potential of the emerging field of phosphorus catalysis in chemistry is shown and new developments that may stimulate further research are described.