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Pregled bibliografske jedinice broj: 234229

Protonation of Trimethylsilyl-Substituted Carbon-Carbon Multiple Bonds in Aliphatic Systems. Conformational Dependence of the beta-Silyl Stabilization of Carbocations


Gabelica, Vesna; Kresge, Alexander Jerry
Protonation of Trimethylsilyl-Substituted Carbon-Carbon Multiple Bonds in Aliphatic Systems. Conformational Dependence of the beta-Silyl Stabilization of Carbocations // Journal of the American Chemical Society, 118 (1996), 16; 3838-3841 (međunarodna recenzija, članak, znanstveni)


Naslov
Protonation of Trimethylsilyl-Substituted Carbon-Carbon Multiple Bonds in Aliphatic Systems. Conformational Dependence of the beta-Silyl Stabilization of Carbocations

Autori
Gabelica, Vesna ; Kresge, Alexander Jerry

Izvornik
Journal of the American Chemical Society (0002-7863) 118 (1996), 16; 3838-3841

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Carbocation stabilization; β -silyl effect; conformational dependence

Sažetak
Rates of carbocation protonation to give carbocation products were measured in concentrated perchloric acid solutions for cyclohexene, propyne, 1-hexyne, and their trimethyl-silyl-substituted analogs. The trimethylsilyl substituent accelerated the reaction markedly and provided the following β -silyl carbocation stabilizing effects: δ Δ G≠ = 5.7 kcal/mol-1 for the cyclohexyl systems and δ Δ G≠ = 6.5 kcal/mol-1 for both acetylenic systems. These effects are substantially greater than δ Δ G≠ = 2.9 and 3.4 kcal/mol-1 found previously for the protonation of ethyl vinyl ether and phenylacetylene, which suggests that the silyl effects in these previously systems were attenuated by additional carbocation stabilization provided through their ethoxy and pheny groups. The present effects, on the other hand, fall far short of δ Δ G≠ = 16-17 kcal/mol-1 found for conformationally optimum systems. The influence of conformation on the magnitude of β -silyl effects and how this impinges on the presently studied systems is discussed.

Izvorni jezik
Engleski

Znanstvena područja
Kemija



POVEZANOST RADA


Autor s matičnim brojem:
Vesna Gabelica Marković, (138402)

Časopis indeksira:


  • Current Contents Connect (CCC)
  • Web of Science Core Collection (WoSCC)
    • SCI-EXP, SSCI i/ili A&HCI


Uključenost u ostale bibliografske baze podataka:


  • Chemical Abstracts