Anchimeric assistance by and migration of the vinyl group in reactions of sterically hindered organosilicon compounds of the type (Me<sub>3</sub>Si)<sub>2</sub>C(SiMe<sub>2</sub>CHCH<sub>2</sub>)(SiR<sub>2</sub>X)
作者:G. Adefikayo Ayoko、Colin Eaborn
DOI:10.1039/p29870001047
日期:——
The compound VsiSiMe2I [Vsi =(Me3Si)2C(SiMe2CHCH2)](1) is very similar in reactivity to (Me3Si)3CSiMe2I (2) in reactions with methanol and with alkali-metal salts in MeOH or MeCN, but (1) is much the more reactive towards electrophiles which induce rate-determining ionization of the Si–I bond, viz. CF3CH2OH (the factor f is > 500), CF3CO2H (f > 1 800), AgBF4 in CH2Cl2(f ca. 150), or AgSCN in CH2Cl2(f
Unimolecular solvolysis of some organosilicon perchlorates and iodides
作者:Colin Eaborn、Foad M. S. Mahmoud
DOI:10.1039/p29810001309
日期:——
TsiSiMe2OH. The solvolysis is slower in EtOH and PriOH, and occurs only very slowly, if at all, in CF3CH2OH. The methanolysis of (Me3Si)2(Ph2MeSi)CSiMe2OClO3 is slower than that of TsiSMe2OClO3. The methanolysis of TsiSiHPhl and TsiSiHMel are also accelerated only to a small extent by NaOMe. The above results are interpreted in terms of an SN1 mechanism involving anchimericallyassisted ionization of
[Tris(trimethylsllyl)methyl](dimethyl)silyl cyanate. The cyanate to isocyanate isomerization, and the high activity of cyanate as a leaving group in solvolysis
作者:Colin Eaborn、Yousef Y. El-Kaddar、Paul D. Lickiss
DOI:10.1039/c39830001450
日期:——
The isomerization of the cyanate (Me3Si)3CSiMe2(OCN), (1), to the isocyanate (i) in Ph2O at 195 °C is second order in (1), (ii) in CCl4 is catalysed by ICI, and (iii), in MeOH is catalysed by NaOMe; in solvolysis in MeOH, (1) is comparable in reactivity to the corresponding trifluoromethanesulphonate, and shows an abnormally high selectivity for reaction with the water in slightly aqueous MeOH.
Oxidatively assisted nucleophilic substitution of organosilicon iodides
作者:Abdulaziz I. Al-Wassil、Colin Eaborn、Anil K. Saxena
DOI:10.1039/c39830000974
日期:——
The iodides (Me3Si)3CSiMe2I, (Me3Si)3CSiPh2I, and But3SiL react with m-chloroperoxybenzoic acid to give the hydroxides (Me3Si)3CSiMe2OH, (Me3Si)2C(SiPh2Me)(SiMe2OH), and But3SiOH, respectively in MeOH (Me3Si)3CSiPh2I suggests the participation of silico-cationic intermediates.
Bimolecular displacements of iodine in reactions of dimethyl[tris(trimethylsilyl)methyl]silyl iodide with salts
作者:Saman A.I. Al-Shali、Colin Eaborn
DOI:10.1016/0022-328x(83)80204-6
日期:1983.4
Direct nucleophilic displacement of iodine to give (Me3Si)3 CSiMe2 Y, where Y = F, NCO, NCS, CN or N3, takes place when (Me3Si)3 CSiMe2I is treated with solutions of CsF, KOCN, KSCN, KCN, or NaN3 in MeOH or CH3 CN. The order of effectiveness of the nucleophiles appears to be N3 > F > CN > NCS > NCO in MeOH and NCS > NCO > CN, F in CH3 CN.