Organocatalyzed direct asymmetric aldol reaction of isatins in water: low catalyst loading in command

Simple primary–tertiary diamines easily derived from natural primary amino acids have been used to catalyze the aldol reactions in water. The 1 mol % of diamine catalyst is sufficient to catalyze the aldol reaction of cyclohexanone/acetone to isatins provided 3-substituted-3-hydroxy-2-oxindole in good yield and good enantioselectivity. The methodology highlights the importance of low catalyst loading in achieving high enantioselectivity.