Bis(diethylamino)chlorophosphine is an organophosphorus compound with the formula (Et<sub>2</sub>N)<sub>2</sub>PCl (Et = ethyl). This colorless liquid serves as a masked source of PCl<sub>2</sub><sup>+</sup>.
Synthesis and reactions
The compound is prepared by treatment of phosphorus trichloride with diethylamine:
4 Et<sub>2</sub>NH + PCl<sub>3</sub> â (Et<sub>2</sub>N)<sub>2</sub>PCl + 2 Et<sub>2</sub>NH<sub>2</sub>Cl
Illustrative 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 (Et<sub>2</sub>N)<sub>2</sub>PCl:
C<sub>6</sub>H<sub>4</sub>Br<sub>2</sub> + BuLi â C<sub>6</sub>H<sub>4</sub>(Br)Li + BuBr
C<sub>6</sub>H<sub>4</sub>(Br)Li + (Et<sub>2</sub>N)<sub>2</sub>PCl â C<sub>6</sub>H<sub>4</sub>(Br)(P(NEt<sub>2</sub>)<sub>2</sub>) + LiCl
C<sub>6</sub>H<sub>4</sub>(Br)(P(NEt<sub>2</sub>)<sub>2</sub>) + BuLi â C<sub>6</sub>H<sub>4</sub>(Li)(P(NEt<sub>2</sub>)<sub>2</sub>) + BuBr
C<sub>6</sub>H<sub>4</sub>(Li)(P(NEt<sub>2</sub>)<sub>2</sub>) + (Et<sub>2</sub>N)<sub>2</sub>PCl â C<sub>6</sub>H<sub>4</sub>[P(NEt<sub>2</sub>)<sub>2</sub>]<sub>2</sub> + LiCl
Finally, the amino substituents are removed using hydrogen chloride:
C<sub>6</sub>H<sub>4</sub>[P(NEt<sub>2</sub>)<sub>2</sub>]<sub>2</sub> + 8 HCl â C<sub>6</sub>H<sub>4</sub>(PCl<sub>2</sub>)<sub>2</sub> + 4 Et<sub>2</sub>NH<sub>2</sub>Cl
References