Geometrically Constrained Phosphenium Cations - Synthesis and Reactivity With Small Molecules

Geometrically constrained phosphines of type A are capable of activating small molecules, such as: NH₃BH₃, NH₃, RNH₂, H₂O, ROH and HBpin. Using this reactivity various catalytic processes were achieved. However, up to date, species of type A were unable to activate H₂, HSiEt₃. The growing interest in activation of these small molecules due to their synthetic potential motivated us to design reactive P-based compounds. The strategy we chose is to prepare a compound of type A with a positive charge on the P center, i.e. to synthesize geometrically constrained phosphenium cations (GCPCs, B). Herein we present the synthesis of new GCPCs and their reactivity with small molecules.