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Updated: Jun 24, 2026

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
Pd-catalyzed arylation of silyl enol ethers of substituted alpha-fluoroketones
Yong Guo1, Brendan Twamley, Jean'ne M Shreeve
1Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, USA.
Abstract:
Alpha-fluoro-alpha-aryl-ketones were synthesized by the Pd-catalyzed cross-coupling of aryl bromides with either alpha-fluoroketones or their corresponding silyl enol ethers. The direct arylation with an alpha-fluoroketone requires a strong base, such as potassium tert-butoxide, and under these conditions the presence of a base-sensitive functional group is not compatible. However, good functional tolerance was achieved when the anionic coupling moieties were generated from the silyl enol ethers obtained by reacting alpha-fluoroketones with tetrabutylammonium (tripheny1silyl)difluorosilicate (TBAT) as the fluoride source under nearly neutral conditions. The aryl halides with a carbmethoxy, nitro, cyano or carbonyl group were used. The reaction with nonfluorinated silyl enol ether 1h gave a cross-coupling product in low yield.
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