PHOSPHONIO-SUBSTITUTED 1,3-DIPHOSPHANAPHT HALENES FROM THE ALPHA,O-CONDENSATION OF PHOSPHONIUM-BENZYLIDES

Triphenylphosphonium 1-trimethylsilylbenzylides 1 react with the bis(d ichlorophosphino)-substituted ylide 2 both at their 1- and ortho-posit ion to yield 1,3-diphosphatetraline derivatives 4 containing two ylide and PCl units each as alternating ring members. The two PCl groups di ffer decisively in their spontaneous dissociation in a polar medium, a s well as in their oxidation by elemental sulfur. With gallium trichlo ride dicationic 1,3-diphosphanaphthalenes (1,3-benzodiphosphinines) ar e formed, in which both phosphorus ring members achieve two-coordinati on and which represent a novel pi(10) system.