Highly efficient prolinamide-based organocatalysts for the direct asymmetric aldol reaction in brine

Four prolinamide-based organocatalysts were readily synthesized and applied to the direct asymmetric aldol reactions of ketones and aromatic aldehydes in brine. When 2,4-dinitrophenol (DNP) was used as an acidic additive, 1 mol % low loading of 2b afforded aldol products with excellent diastereoselectivity of up to 98/2 dr and high enantioselectivity of up to 97% ee.