Disclosed are compounds of formula (I) and formula (II-a) and methods of making said compounds, wherein the substituents are as defined in the specification. The compounds are useful for treating a cancer characterized by the presence of a mutant allele of IDH1/2. Examples of a compound of formula (I) are: (S)-N-((S)-1-(2-chlorophenyl)-2-((4,4-difluorocyclohexyl)amino)-2-oxoethyl)-N-(3-fluoro-phenyl)-5-oxo-1-(pyrimidin-2-yl)pyrrolidine-2-carboxamide (S)-N-((S)-1-(2-chlorophenyl)-2-(3,3-difluorocyclobutylamino)-2-oxoethyl)-N-(3-fluorophenyl)-5-oxo-1-(thiazol-4-yl)pyrrolidine-2-carboxamide (2S)-N-(1-(2-Chlorophenyl)-2-((3,3-difluorocyclopentyl)amino)-2-oxoethyl)-N-(3-fluorophenyl)-5-oxo-1-(pyrimidin-2-yl)pyrrolidine-2-carboxamide
