Phosphorus as a Lewis Acid: CO₂ Sequestration with Amidophosphoranes

CO2 snapper: Compounds containing both acidic and basic P,N functionalities have been prepared. Of these, two amidophosphoranes containing highly reactive PN bonds within four-membered rings react rapidly with CO2, resulting in relief of ring strain. These compounds demonstrate the utility of phosphorus as a Lewis acid for small-molecule activation.