Bis(difluoromethyl)trimethylsilicate Anion: A Key Intermediate in Nucleophilic Difluoromethylation of Enolizable Ketones with Me3SiCF2H

Abstract

AbstractA pentacoordinate bis(difluoromethyl)silicate anion, [Me3Si(CF2H)2]−, is observed for the first time by the activation of Me3SiCF2H with a nucleophilic alkali‐metal salt and 18‐crown‐6. Further study on its reactivity by tuning the countercation effect led to the discovery and development of an efficient, catalytic nucleophilic difluoromethylation of enolizable ketones with Me3SiCF2H by using a combination of CsF and 18‐crown‐6 as the initiation system. Mechanistic investigations demonstrate that [(18‐crown‐6)Cs]+[Me3Si(CF2H)2]− is a key intermediate in this catalytic reaction.