Remarkable Brönsted type correlation for base cleavage of carbon–silicon bonds. Kinetic isotope effects for interaction of carbanions with methanol

Abstract

The logarithms of the relative rates of cleavage of RSiMe₃ compounds [R = 1-indenyl, 9-fluorenyl, 9-(2-bromofluorenyl), 9-(2,7-dibromofluorenyl), PhC⋮C, Ph₃C, Ph₂CH, p-PhC₆H₄CH₂, and PhCH₂] by aqueous methanolic alkali correlate linearly with the pK's of the corresponding hydrocarbons R–H over a pK_a range of 22 units; the ratio of RH/RD products obtained in 1:1 MeOH–MeOD is thought to be equal to the deuterium isotope effect for interaction of the carbanion R^– with methanol.