SILICIUMVERBINDUNGEN MIT STARKEN INTRAMOLEKULAREN STERISCHEN WECHSELWIRKUNGEN. XXIV. CYCLOHEXYLSUBSTITUIERTE DISILANE: DARSTELLUNG UND REAKTIONEN VON DISILENYL-RADIKALANIONEN, 2,3:5,6-DIBENZO-7,8-DISILABICYCLOOCTA-2,5-DIENEN UND EINES CYCLOTETRASILANS

Article abstract of DOI:10.1016/S0022-328X(00)99533-0

Treatment of 1,2-di-t-butyl-1,2-dicyclohexyl-1,2-dichlorodisilane (5b) with excess lithium yields the long-lived radical anion t-Bu(Cy)Si=Si(Cy)t-Bu^-., which has been characterized by its ESR spectra.Reaction of 5 as well as 1,1,2,2-tetracyclohexyl-1,2-dihalodisilanes (6) with lithium in the presence of anthracene gives 7,8-tetraorganyl-2,3:5,6-dibenzo-7,8-disilabicyclo<2.2.2>octa-2,5-dienes which can be cleaved photochemically forming the corresponding cyclotetrasilanes.In the presence of phenylacetylene 5 and 6 react with lithium to give the 1,2-bis(phenilethynyl)-substituted disilanes and 3,4,5,6-tetra-t-butyl-3,4,5,6-tetracyclohexyl-2-phenyl-3,4,5,6-tetrasilacyclohexen-1, respectively.The latter compound is also obtained by phenylacetylene insertion into 1,2,3,4-tetra-t-butyl-1,2,3,4-tetracyclohexylcyclotetrasilane.