Redistribution reactions of alkoxy- and siloxysilanes, catalyzed by dimethyltitanocene

Abstract

Can. J. Chem. 68, 471 (1990). Dimethyltitanocene is an excellent catalyst for the redistribution of alkoxy-and siloxyhydrosilanes. The redistribution reactions of triethoxysilane, diethoxymethylsilane, 1,3,5,7-tetramethylcyclotetrasiloxane, pentamethyldisiloxane, and H-(SiMe20),-SiMe2H ( n = 1 to 3) are described. The mechanism of these reactions is discussed in terms of TiH mediated displacements. The possibility of both Ti(II1) and Ti(IV) mediated displacements are considered and a mechanism involving the former, which fits all of the experimental data, is proposed.Key words: siloxanes, alkoxysilanes, redistribution, catalysis, dimethyltitanocene.SHIXUAN XIN, CLARE AITKEN, JOHN F. HARROD, YING MU et E. SAMUEL. Can. J. Chem. 68, 471 (1990) Le dimkthyltitanoc&ne est un excellent catalyseur pour la redistribution des alcoxy-et siloxyhydrosilanes. On dCcrit les rCactions de redistribution du triCthoxysilane, du diCthoxymCthylsilane, du 1,3,5,7-t~tramCthylcyclotCtrasiloxane, du pentamCthyldisiloxane et des H-(SiMe20),-SiMe2H( n = 1 a 3). On discute du mkcanisme de ces rkactions en fonction de dCplacements effectuCs sous l'influence du TiH. On a considCrC la possibilitC que les dCplacements s'effectuent sous l'influence du Ti(II1) ainsi que du Ti(1V) et on propose une mecanisme impliquant le premier qui permet d'expliquer l'ensemble des donnCes expCrimentales.

Direct Production of Silicones From Sand

“…This result suggests that MeSi(OMe)3 is formed from intermediately formed HSi(OMe)3. Significant disproportionation of HSi(OMe)3 into SiH4 and Si(OMe)4 was observed, a reaction with precedence in the literature (19,20). Deprotonation of HSi(OMe)3 by NaH to form a sodium silyl species is a conceivable first step in the formation of MeSi(OMe)3 from HSi(OMe)3.…”

Nucleophile induced ligand rearrangement reactions of alkoxy- and arylsilanes

“…While hydrosilane reagents show a wide breadth of reactivity in reductive transformations, they have often been observed to undergo ligand-redistribution reactions (Scheme 1, c) [8]. Most commonly ligand-redistribution reactions of arylsilanes have been observed using metal complexes as catalysts; including: Ir [9], Pd [10], Sm [11], Mo [12], Co [13], Ti [14], Yb [15] and Ru [16]. Similarly, a number of hydride sources, including LiAlH4, KH and NaH, have proven effective towards ligand-redistribution [17].…”

Catalytic Formation of Silicon–Heteroatom (N, P, O, S) Bonds

“…Developments in methods for C−C bond formation are some of the most important in modern chemistry, because they allow complex organic structures to be constructed in a green‐friendly manner . On the other hand, the history of dehydrogenative coupling between silanes and amines (or ammonia) goes back to the late 1960s (Scheme ), when several other pioneering papers were published . Novel catalysts have also recently been involved, and this has led to the dehydrogenative coupling of hydrosilanes with amines (or ammonia) in a more practical manner …”