Asymmetric cross-aldol reactions of α-keto hydrazones and α,β-unsaturated γ-keto hydrazones with trifluoromethyl ketones.

Abstract

α-Keto hydrazones and α,β-unsaturated γ-keto hydrazones are suitable pro-nucleophiles for asymmetric cross-aldol reactions with trifluoromethyl ketones via aza-di(tri)enamine-type intermediates. A quinidine-derived primary amine catalyst affords tertiary trifluoromethylated alcohols in good-to-excellent yields and high enantioselectivities. Subsequent transformations of hydrazono moieties yield appealing fluorinated carboxylic acids, 1,4-dicarbonyls and γ-keto acids.