SILICIUM-VERBINDUNGEN MIT STARKEN INTRAMOLEKULAREN STERISCHEN WECHSELWIRKUNGEN X. NEUE WEGE ZU 1,3,2,4-DITHIADISILETANEN

Article abstract of DOI:10.1016/S0022-328X(00)90001-9

2,2,4,4-Tetraorganyl-1,3,2,4-dithiadisiletanes containing bulky organyl groups are obtained by copyrolysis of the disilanes R3Si-SiR3 with sulfur or sulfur hexafluoride, or better by reaction of the disilanes R2HSi-SiHR2 (R=CH3, i-C3H7, cyclo-C6H11, t-C4H9) with sulfur.In the case of R=t-C4H9 a considerable amount of the t-butyl groups is isomerized to the less crowded isobutyl groups.Monomeric silathiones R2Si=S are not available by this route.The sulfur insertion reaction into 1,1-di-t-butyl-1-silacyclobutane yields 2,4-di-t-butyl-2,4-dipropyl-1,3,2,4-dithiadisiletane instead of the expected 1,1-di-t-butyl-1-sila-2-thiacyclopentane.The latter compound, however, results from the crown ether catalyzed cyclisation reaction of 3-bromopropyltrichlorosilane with Na2S followed by transalkylation with t-butyllithium.The iodosilanes R3SiI (R=i-C3H7, cyclo-C6H11) react with Na2S to give the corresponding hexaorganyldisilathianes in high yields.