Nucleophilic cleavage of the Si-C bond in organotrifluorosilanes and diorganodifluorosilanes

Article abstract of DOI:10.1016/0022-328X(88)89077-6

The Si-C bond in aryltrifluorosilanes, 4-XC6H4SiF3 (X = H, CH3, Cl, Br or NO2), is readily cleaved by mercury(II) salts HgY2 (Y = Cl, Br, I, CN or OCOCH3) or HgO to form organomercurials of the type 4-XC6H4HgY or (4-XC6H4)2Hg, respectively.Electron-donating substituent X facilitate the reaction, whereas electron-withdrawing substituents make it more difficult.Mercury(II) salts and mercury(II) oxide also cleave the Si-C bond in chloromethyltrifluorosilanes, F3Si(CH_3-nCl_n) (n = 1-3) to produce the corresponding organic mercurials containing an Hg(CH_3-nCl_n) group.The substitution of the fluorine atom in organotrifluorosilanes by an alkyl group hinders the bond cleavage between the silicon atom and the electronegative organic substituent.The reactions studied are believed to follow a nucleophilic mechanism involving asynchronous formation of a four-centered transition state with a pentacoordinate silicon atom.