PROTONATION OF PHENYL(TRIMETHYLSILYL)ACETYLENE - A SURPRISINGLY WEAK STABILIZATION OF A CARBOCATION BY A BETA-TRIMETHYLSILYL GROUP

Authors
KRESGE AJ TOBIN JB
Citation
Aj. Kresge et Jb. Tobin, PROTONATION OF PHENYL(TRIMETHYLSILYL)ACETYLENE - A SURPRISINGLY WEAK STABILIZATION OF A CARBOCATION BY A BETA-TRIMETHYLSILYL GROUP, Angewandte Chemie, International Edition in English, 32(5), 1993, pp. 721-723
Citations number
28
Categorie Soggetti
Chemistry
Journal title
Angewandte Chemie, International Edition in English → ACNP
ISSN journal
05700833
Volume
32
Issue
5
Year of publication
1993
Pages
721 - 723
Database
ISI
SICI code
0570-0833(1993)32:5<721:POP-AS>2.0.ZU;2-U
Abstract
The protodesilylation of the title compound 1 [Eq. (a)] proceeds via t he vinyl cation 2, whose stabilization by the beta-trimethylsilyl grou p is much smaller than expected, The comparison of the rate of protona tion of 1 and that of phenyl-acetylene gives a small beta-silyl stabil izing effect (DELTADELTAG(not-equal) = 3.4 kcal mol-1). This surprisin g result is explained by insufficient hyperconjugation. [G