“…It was claimed that controlled-potential electrolysis in the presence of added water yielded partial and complete reduction of the diene system, although no stable products could be isolated. Following our investigation of electrochemical oxidation of cyclic polysilicon compounds [10][11][12][13][14][15], we reported the first electrochemical example of preparative electrolysis of 1,1-bis(trimethylsilyl)-2,3,4,5-tetraphenyl-1-silacyclopentadiene [16] under various conditions. The present work extends (Scheme 1) the cyclic voltammetric measurements to 11 other 2,3,4,5-tetraphenyl-1-silacyclopentadienes 1 [1,1-dihydro-(I); 1-chloro-1-hydro(II); 1-chloro-1-phenyl-(III); 1,1-dichloro-(IV); 1-chloro-1-methyl-(V); 1-chloro-1-phenyl-(VI); 1-chloro-1-(phenylacetylene)-(VII); 1,1-dimethyl-(VIII); 1-methyl-1-phenyl-(IX); 1,1-bis(trimethylsilyl)-(X); 1,1-bis(trimethylstannyl)-(XI); four bicyclic compounds of 2,2 0 ,3,3 0 ,4,4 0 ,5,5 0 -octaphenyl bisiloles bonded through Si-Si bonds (1,1 0 -dimethyl-(XII); 1,1 0 -diphenyl-(XIII); 1,1 0 -dibenzyl-(XIV) and 1,1 0 -bis(trimethylstannyl)-(XV), and a spiro derivative XVI].…”