Nucleophilic Reactivities of Silyl Ketene Acetals and Silyl Enol Ethers Containing (C6F5)3SiO and (C6H5)3SiO Groups

Nucleophilic Reactivities of Silyl Ketene Acetals and Silyl Enol Ethers Containing (C6F5)3SiO and (C6H5)3SiO Groups Full article

Journal

European Journal of Organic Chemistry
ISSN: 1434-193X , E-ISSN: 1099-0690

Output data

Year: 2005, Volume: 2005, Number: 9, Pages: 1760-1764 Pages count : 5 DOI: 10.1002/ejoc.200400706

Authors

Dilman Alexander D. ¹ , Mayr Herbert ²

Affiliations

1	N. D. Zelinsky Institute of Organic Chemistry, 119991 Moscow, Leninsky prosp. 47, Russian Federation, Fax: +7-095-135-5328
2	Department Chemie und Biochemie der Ludwig-Maximilians-Universität, München, Butenandtstr. 5–13 (Haus F), 81377 München, Germany, Fax: +49-89-2180-77717

The kinetics of the reactions of tris(pentafluorophenyl)silyl and triphenylsilyl ketene acetals and enol ethers with benzhydrylium cations have been measured photometrically. The second-order rate constants (log k2) have been used to determine the nucleophilicity parameters of these π systems, which provide a quantitative comparison of their reactivities with those of other types of nucleophiles. A change from trimethylsilyloxy to triphenylsilyloxy reduces reactivity by only a factor of ten, while replacement of triphenylsilyloxy with tris(pentafluorophenyl)silyloxy decreases the nucleophilicity of the enolate C=C double bond by three to four orders of magnitude. The cation-stabilizing ability of the tris(pentafluorophenyl)silyloxy group is thus similar to that of a methyl group.

Dilman A.D. , Mayr H.
Nucleophilic Reactivities of Silyl Ketene Acetals and Silyl Enol Ethers Containing (C6F5)3SiO and (C6H5)3SiO Groups
European Journal of Organic Chemistry. 2005. V.2005. N9. P.1760-1764. DOI: 10.1002/ejoc.200400706 WOS Scopus OpenAlex

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