[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.
The mechanism of the isomerization of organosilicon cyanates to isocyanates
作者:Abdulrahman I Almansour、G.Adefikayo Ayoko、Colin Eaborn
DOI:10.1016/0022-328x(95)06034-t
日期:1996.5
Isomerization of the cyanate (Me(3)Si)(3)CSi(CD3)(2)OCN in the molten state at 150 degrees C gives the unrearranged isocyanate (Me(3)Si)(3)CSi(CD3)(2)NCO and the rearranged isocyanate (Me(3)Si)(2)[(CD3)(2)MeSi]CSiMe(2)NCO in a ratio of ca. 75/25, and isomerization in solution in Ph(2)O at 220 degrees C gives the same products in a ratio of ca. 85/15. The occurrence of a significant amount of rearrangement is consistent with a mechanism involving initial ionization of the cyanate. In contrast, no rearrangement accompanies the isomerization in CCl4 catalyzed by ICI, indicating that ionization is not involved; this conclusion is supported by the observation that the isomerization of (Me(3)Si)(2)(PhMe(2)Si)CSiMe(2)OCN, in which the Ph group would provide anchimeric assistance to ionization, proceeds at a similar rate to that of (Me(3)Si)(3)CSiMe(2)OCN.
El-Kaddar, Yousef Y.; Eaborn, Colin; Lickiss, Paul D., Journal of the Chemical Society. Perkin transactions II, 1992, # 10, p. 1753 - 1759
作者:El-Kaddar, Yousef Y.、Eaborn, Colin、Lickiss, Paul D.、Reed, David E.