Versatile Reagent Ph3As(OTf)2: One-Pot Synthesis of [P7(AsPh3)3][OTf]3 from PCl3

Compound Ph3As(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 Me3SiOTf and facilitates the reductive coupling of PCl3 in the presence of AsPh3 to the unprecedented cation [P-7(AsPh3)(3)](3+) as triflate salt. This crystallographically characterized nortricyclane-type cation represents a P7R3-derivative with the most electron-withdrawing substituents, resulting in a pronounced effect on the structural parameters of the P-7 core.