Direct Catalytic Asymmetric Aldol Reaction of α-Alkoxyamides to α-Fluorinated Ketones.

α-Oxygen-functionalized amides found particular utility as enolate surrogates for direct aldol couplings with α-fluorinated ketones in a catalytic manner. Because of the likely involvement of open transition states, both syn- and anti-aldol adducts can be accessed with high enantioselectivity by judicious choice of the chiral ligands. A broad variety of alkoxy substituents on the amides and aryl and fluoroalkyl groups on the ketone were tolerated, and the corresponding substrates delivered a range of enantioenriched fluorinated 1,2-dihydroxycarboxylic acid derivatives with divergent diastereoselectivity depending on the ligand used. The amide moiety of the aldol adduct was transformed into a variety of functional groups without protection of the tertiary alcohol, showcasing the synthetic utility of the present asymmetric aldol process.