Design of Threonine‐Derived Amino Sulfonamide Organocatalysts for the Highly Stereoselective Aldol Reactions

Abstract Novel threonine‐derived amino sulfonamide organocatalysts were developed and applied to the asymmetric aldol reactions. The reactions of cyclohexanones with aromatic aldehydes catalyzed by the threonine‐derived tosylamide provided anti ‐aldol adducts in good yield with high diastereo‐ and enantioselectivity. On the other hand, syn ‐aldol adducts were obtained in the reactions between α‐siloxyacetone and aromatic aldehydes using threonine‐derived triflamide catalyst. In both cases, a significant improvement in diastereoselectivity was observed compared to threonine‐derived carboxylic acid catalyst.