Theoretical study on the nucleophilic fluoroalkylation of propylene oxide with fluorinated sulfones

Abstract

The path of nucleophilic fluoroalkylation reaction of propylene oxide with PhSO2CYF- (Y=F,H, and PhSO2, respectively) in gas phase and in Et2O solvent were studied theoretically. The nucleophilic fluoroalkylation of propylene oxide with fluorinated carbanions was probed by the reactivity comparison between (benzenesulfonyl)monofluoromethyl anion (PhSO2CHF-), (benzenesulfonyl) difluoromethyl anion (PhSO2CF2-), and bis(benzenesul-fonyl) monofluoromethyl anion ((PhSO2)2CF-). The nucleophilicity reactivity order of PhSO2CYF- (Y = F, H, and PhSO2) is [(PhSO2)2CF-] > PhSO2CHF- > PhSO2CF2-, which indicates that introducing another electron-withdrawing benzenesulfonyl group is an effective way to significantly increase the nucleophilicity of the fluorinate carbanions. For comparison, we also studied the nucleophilic addition reactions of propylene oxide with chlorine substituted carbanion PhSO2CHCl-. The calculated results show that the nucleophilicity of PhSO2CYF- is better than that of PhSO2CHCl- for the ring opening reaction with propylene oxide. The calculated results are in good agreement with the available experiments.