72190-83-1Relevant articles and documents
Unimolecular Solvolysis of Some Organosilicon Perchlorates and Iodides
Eaborn, Colin,Mahmoud, Foad M. S.
, p. 1309 - 1315 (1981)
Kinetic studies have been made of the solvolysis (mainly the methanolysis) of the highly sterically hindered compounds TsiSiMe2OClO3 , (Me3Si)2(Ph2MeSi)CSiMe2OClO3, TsiSiHPhX (X=I, Br, ONO2), and TsiSiHMeI.The rate of methanolysis of TSiMe2OClO3 is increased by only ca.20percent upon addition of 0.1 M-NaOMe, and further additions of base have smaller effects.Additions of LiCl or LiNO3 cause even smaller rate increases, but in the presence of LiNO3 substantial amounts of TsiSiMe2ONO2 are formed, the amounts being greater than would correspond to the rate increases.Water has a very large accelerating effect, and even with only 1 vol percent of water present the product is very predominantly TsiSiMe2OH.The solvolysis is slower in EtOH and i-PrOH, and occurs only very slowly, if at all, in CF3CH2OH.The methanolysis of (Me3Si)2(Ph2MeSi)CSiMe2OClO3 is slower than that of TsiMe2OClO3.The methanolysis of TsiSiHPhI and TsiHMeI are also accelerated only to a small extent by NaOMe.The above results are interpreted in terms of an SN1 mechanism involving anchimerically assisted ionization of the Si-OClO3 or Si-I bond to give a methyl-bridged cation with unusual solvation requirements.In contrast, the methanolyses of TsiSiHPhX (X = Br or ONO2) are markedly accelerated by base, and it seems that, at least in the presence of base, attack by the nucleophile is involved in the rate-determining step in these cases.
Rate-determining Ionization in Methanolysis of an Organosilicon Halide
Eaborn, Colin,Mahmoud, Foad M. S.
, p. 63 - 64 (2007/10/02)
Methanolysis of (Me3Si)3CSiPhHI is not significantly accelerated by NaOMe, and so is thought to involve rate-determining ionization of the iodide.
