To a mixture of 3-isopropyl-2-oxopyrrolidine-3-carbonitrile (120 mg) obtained in Step B, 2,4-dichloropyrimidine (240 mg), cesium carbonate (510 mg) and 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (27 mg) in tetrahydrofuran (3 mL) was added tris(dibenzylideneacetone)dipalladium(0) (14 mg), and the mixture was stirred overnight at 100° C. To the reaction mixture was added water, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, and dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate) to give the title compound (160 mg).
