Fragmentation-Related Phosphinylation and Phosphonylation of Nucleophiles Utilising the Bridging P-Unit of 2-Phosphabicyclo[2.2.2]oct-5-ene Derivatives

The synthesis of phosphonic and phosphinic derivatives comprises the use of the corresponding phosphorus chlorides. A novel approach applies low-coordinated P-species, methylenephosphine oxides (YP(O)CH2, Y =Ar, alkyl, alkoxy), which can be generated by the fragmentation of bridged P-heterocycles, 2- phosphabicyclo[2.2.2]oct-5-enes available by Diels-Alder cycloadditions. The fine tuning between the structure and reactivity of different type of precursors is discussed. Thermolysis or photolysis of the suitable phosphabicyclooctenes in the presence of hydroxy compounds or amines affords a rich variety of phosphinic or phosphonic derivatives. The potential of the photolysis is that it requires mild conditions (26°C) and that it is highly efficient.