Bis(diethylamino)chlorophosphine explained

Bis(diethylamino)chlorophosphine is an organophosphorus compound with the formula (Et₂N)₂PCl (Et = ethyl). This colorless liquid serves as a masked source of PCl₂⁺.

Synthesis and reactions

The compound is prepared by treatment of phosphorus trichloride with diethylamine:

4 Et₂NH + PCl₃ → (Et₂N)₂PCl + 2 Et₂NH₂ClIllustrative of its utility is the synthesis of 1,2-bis(dichlorophosphino)benzene. The synthesis involves sequential lithiation of 1,2-dibromobenzene followed by treatment with (Et₂N)₂PCl:^[1]

C₆H₄Br₂ + BuLi → C₆H₄(Br)Li + BuBr

C₆H₄(Br)Li + (Et₂N)₂PCl → C₆H₄(Br)(P(NEt₂)₂) + LiCl

C₆H₄(Br)(P(NEt₂)₂) + BuLi → C₆H₄(Li)(P(NEt₂)₂) + BuBr

C₆H₄(Li)(P(NEt₂)₂) + (Et₂N)₂PCl → C₆H₄[P(NEt₂)₂]₂ + LiCl

Finally, the amino substituents are removed using hydrogen chloride:

C₆H₄[P(NEt₂)₂]₂ + 8 HCl → C₆H₄(PCl₂)₂ + 4 Et₂NH₂Cl

References

1. 10.1021/ol010219y. 11735590. BINOL-Based Diphosphonites as Ligands in the Asymmetric Rh-Catalyzed Conjugate Addition of Arylboronic Acids. Organic Letters. 3. 25. 4083–4085. 2001. Reetz. Manfred T.. Moulin. Dominique. Gosberg. Andreas.