Reaction of dimethyldiethynylsilane with 1,2-dichlorodiselane

Abstract

In continuation of our studies of the reactions of selenium halides with bridged diacetylenes, like diorganyldiethynylsilanes R2Si(C≡CH)2 and -germanes R2Ge(C≡CH)2, leading in the case of SeCl2 and SeBr2 to the five-membered unsaturated selenium, siliconand selenium,germanium-containing heterocycles having the fulvene structure [1–3], we have studied the reaction of dimethyldiethynylsilane with 1,2-dichlorodiselane Se2Cl2. Addition of Se2Cl2 to terminal acetylenes in DMF is known to result in the formation of diselenides by the mechanism of anti-addition [4], while the reaction with phenylacetylenes PhCoCR is followed by intramolecular cyclization with elimination of selenium and formation of benzoselenophenes [4]. With acetylene, Se2Cl2 also reacts with elimination of selenium and formation of the E-isomer of 2-chloroethenylselenenylchloride [5]. In a similar manner, that is, with elimination of sulfur, proceeds the reaction of sulfur monochloride S2Cl2 with two molecules of diphenylacetylene leading to the substituted divinylsulfide rather than the anticipated disulfide [6].