The fluorinated trimethylsilyl enol ethers 3a–c were synthesized, and the kinetics of their reactions with the benzhydrylium ions 4 was studied by UV–vis spectroscopy in dichloromethane. Comparison with nonfluorinated analogues shows that replacement of CH3 by CF3 reduces the nucleophilic reactivity by 8 orders of magnitude, while the exchange of C6H5 by C6F5 retards the reactions by 4.5 orders of magnitude.
