Versatile reagent Ph3 As(OTf)2: one-pot synthesis of [P7(AsPh3)3][OTf]3 from PCl3.

Compound Ph3 As(OTf)2 as a pentacoordinated As(V) Lewis acid readily forms dicationic Lewis acid/base adducts upon addition of various Lewis bases. It also represents a stronger chloride-abstracting agent than Me3 SiOTf and facilitates the reductive coupling of PCl3 in the presence of AsPh3 to the unprecedented cation P7 (AsPh3 )3 as triflate salt. This crystallographically characterized nortricyclane-type cation represents a P7 R3 -derivative with the most electron-withdrawing substituents, resulting in a pronounced effect on the structural parameters of the P7 core.