New Organosilicon Chemistry

The formation of siloxymethylamine intermediates R3SiOCH 2NMe2, 1, as initial products of the reduction of DMF by hydrosilanes catalyzed by Mo(CO)5NMe3 has been reported. These siloxymethylamines can react with R’3SiH to form trimethylamine and disiloxanes, and with chlorosilanes to form disiloxanes and ClCH 2NMe2, Eschenmoser’s salt. I shall illustrate, in Chapter 1, how attempts to react 1, formed in situ in the presence of chlorosilanes R’3SiCl in the hope producing heterosilyl disiloxanes, R3SiOSiR’3, was not successful but led to a newly discovered activation of the Si-Cl bond by DMF. In Chapter 2, we surmised that 1 acts as a transient siloxy-imminium ion pair [R3SiO]- [CH2NMe2]+, and further suggested that these intermediates could be useful Mannich reagents, dimethylaminomethyl [Me2NCH2] transfer agents. Furthermore, I shall present the reactions between 1 and compounds with a series of E-H bonds (E = O, S, N) which prove its utility and reliability as a new [CH2NMe2] transfer reagent. We have previously reported the formation of a series of group 14 substituted methanes, (R3E)nCH4-n (E = Si, Ge, Sn, Pb; R = combinations of methyl and aryl groups; n = 2,3,4). We also used these materials where an R group = C6H5 to form Cr(CO)3 derivatives. During such studies we observed significant C-E bond cleavage products to form (R3E)n-1CH4-n products. It was proposed that the Cr(CO)3 substituent was responsible for this E-C bond activation. Now we have synthesized silicon and germanium homologous compounds with their Cr(CO)3 derivatives, and will study their hydrolytic stability, Chapter 3. Treatment of arenechromiumtricarbonyl complexes with regular n-Bu2O/THF will also be described to illustrate the potential activation of E-C bonds by the transition metal substituent