The directamination of cyanohydrins with amines via a catalytic cyano-borrowing reaction was developed. The transformation features broad substrate scope, excellent functional group compatibility, and very mild and simple operations. Moreover, a titanium catalyst supported by quinine and (S)-BINOL ligands enabled an asymmetric cyano-borrowing reaction with moderate to high enantioselectivity.
Fully substituted 4-aminopyrrolones are easily accessed via simple routes starting from imines, ketones, or alpha-bromophenyl acetonitriles. Imines were reacted with KCN/NH4Cl in aqueous ethanol to produce alpha-arylamino benzyl cyanides. On the other hand, ketones were transformed to the desired alpha-amino nitriles using a modified Strecker reaction. Then, alpha-amino nitrile precursors were allowed to react with a suitable acyl halide to produce the corresponding amides. Further treatment of these amides with ethanolic KOH converted them to highly substituted 4-amino-1H-pyrrol-2(5H)-one derivatives in moderate to excellent yields.