Carbohydrate-derived alcohols as organocatalysts in enantioselective aldol reactions of isatins with ketones

The catalytic activity of carbohydrate-derived amino alcohols in the enantioselective aldol reaction of ketones with isatin and its derivatives has been examined for the first time. The carbohydrate-derived amino alcohols 5 were found to be efficient organocatalysts for asymmetric aldol reactions. A variety of isatins were used as substrates and the corresponding aldol products were obtained in high yields (up to 99%) and with moderate enantioselectivities (up to 75%).

Figure optionsDownload as PowerPoint slide

(S)-3-(2-Oxopropyl)-3-hydroxyindolin-2-oneC11H11NO3Ee = 67%[α]D25=-18.4 (c 0.82, MeOH)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-1-Methyl 3-(2-oxopropyl)-3-hydroxyindolin-2-oneC12H13NO3Ee = 65%[α]D25=-11.4 (c 0.65, MeOH)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-1-Benzyl 3-(2-oxopropyl)-3-hydroxyindolin-2-oneC18H17NO3Ee = 60%[α]D25=-10.6 (c 0.62, MeOH)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-5-Chloro-3-(2-oxopropyl)-3-hydroxyindolin-2-oneC11H10ClNO3Ee = 72%[α]D25=-16.3 (c 0.77 MeOH)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-5-Bromo-3-(2-oxopropyl)-3-hydroxyindolin-2-oneC11H10BrNO3Ee = 75%[α]D25=-17.6 (c 0.73, MeOH)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-5-Methyl-3-(2-oxopropyl)-3-hydroxyindolin-2-oneC12H13NO3Ee = 63%[α]D25=-11.2 (c 0.52, MeOH)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-(2-Oxocyclohexyl)indolin-3-hydroxyindolin-2-oneC14H15NO3Ee = 63%[α]D25=-12.3 (c 0.61, MeOH)Source of chirality: asymmetric synthesisAbsolute configuration: (S)