Bisprolinediamides with the Binaphthyl Backbone as Organocatalysts for the Direct Asymmetric Aldol Reaction

A series of l-prolineamides derived from various aromatic diamines including 1,1ʹ-binaphthyl-2,2ʹ-diamine, were prepared in good yields. They were evaluated as catalysts for the direct asymmetric aldol reaction. The presence of the binaphthyl and proline moieties in one molecule has beneficial effects on the stereo­chemical outcome of the reaction of acetone with a model aldehyde. Furthermore, it was shown that dioxane as the solvent significantly improved both yield and enantioselectivity, reaching 89% and 86%, respectively.