Reactivity of the pentelidene complexes [Cp*E{W(CO)5}2] (E = P, As) towards dichalcogenides and chalcogenols - synthesis of novel chalcogenopentelidene complexes.

Pentelidene complexes of the type [Cp*E{W(CO)5}2] (Cp* = C5Me5; 1a: E = P, 1b: E = As) were reacted with the dichalcogenides R2Ch2 (R = Ph, Mes, Tipp; Ch = S, Se, Te; Mes = 2,4,6-trimethylphenyl; Tipp = 2,4,6-triisopropylphenyl) and the chalcogenols PhChH (Ch = S, Se). It has been shown that the formation of new E-Ch bonds proceeds under elimination of the Cp* substituent. The resulting chalcogenopentelidene complexes, which have been isolated and fully characterised, represent a novel class of phosphinidene complexes which can be synthesised through this general synthetic route.

Stepwise activation of "non-innocent" Cp* substituents--a Cp* based cascade reaction.

Reactions of Cp* substituted pentelidene complexes with the primary phosphine Cp*PH(2) yield novel polycyclic phosphorus/arsenic and carbon containing cage compounds via cascade-like reactions. These reactions include a sequence of nucleophilic addition reactions, intramolecular hydrophosphination (partially hydroarsination) reactions, retro-Diels-Alder reactions with Cp*H elimination and subsequent [2+4]-cycloadditions.