Dialumene-Mediated Production of Phosphines through P₄ Reduction

The formation of phosphorus-rich alanes featuring butterfly-like geometries is achieved. The two-electron reduction products feature a unique P₄²⁻ structure and can act as a source of P³⁻. The treatment of these phosphorus containing products with electrophiles under mild conditions results in the formation of different phosphines. This approach eliminates the need for high temperatures and/or high pressures, which are commonly required in industrial processes for the preparation of useful phosphines.The activation and further functionalization of white phosphorus (P₄) by main group complexes has become an increasingly studied topic in recent times. Herein, we report the controlled formation of phosphorus-rich alanes featuring butterfly-like geometries from the selective reaction of P₄ with dialumenes, ([L(IiPr)Al]₂) (1: L=Tripp=2,4,6-iPr₃C₆H₂; 2: L=tBu₂MeSi; IiPr=[MeCN(iPr)]₂C)). The two-electron-reduction product of P₄ features a P₄²⁻ structure and is shown to be able to act as a source of P³⁻. Treatments of different electrophiles (e.g., chlorotrimethylsilane (Me₃SiCl), iodotrimethylsilane (Me₃SiI), HCl, or acetyl chloride (CH₃COCl)) with these alanes under mild conditions gave the corresponding phosphines (e.g., P(SiMe₃)₃, PH₃, or P(COCH₃)₃).