Premium
Nucleophilic Reactivities of Silyl Ketene Acetals and Silyl Enol Ethers Containing (C 6 F 5 ) 3 SiO and (C 6 H 5 ) 3 SiO Groups
Author(s) -
Dilman Alexander D.,
Mayr Herbert
Publication year - 2005
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200400706
Subject(s) - ketene , silylation , chemistry , nucleophile , enol , reactivity (psychology) , medicinal chemistry , tris , acetal , reaction rate constant , organic chemistry , kinetics , catalysis , medicine , biochemistry , alternative medicine , pathology , physics , quantum mechanics
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 k 2 ) 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. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Accelerating Research
Robert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom
Address
John Eccles HouseRobert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom