[structure: see text]. Michael addition of various enolates toward gamma-CH(3-n)F(n)-alpha,beta-unsaturated ketones (n = 1-3) was proven to smoothly furnish the 1,4-adducts with high si face selectivities which monotonously decreased by reduction in the number of fluorines. Although the Felkin-Anh model correctly anticipates the present stereochemical outcome only with E-acceptors, the hyperconjugative stabilization of transition states by electron donation from the allylic substituents (the Cieplak rule) successfully explains the pi-facial preference of both acceptors at least in a qualitative level.

The slow inverse addition of an LDA solution at -78 °C to an ester of 2-(trifluoromethyl)acrylic acid enabled efficient dehydrofluorination. Hydrogenation of the resulting difluoromethylacrylate furnished the target ester of 3,3-difluoro-2-methylpropionic acid in good overall yield.

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