A solution of 5-(4-(2,3-di-p-tolyl-7,8-dihydropyrido[2,3-b]pyrazin-5(6H)-yl)butyl)-3-methoxy-4,5-dihydroisoxazole (step 2) (94 mg, 0.2 mmol) in MeOH (3 ml) and water (0.2 ml) was treated with boric acid (37.1 mg, 0.600 mmol) followed by Mo(CO)6 (37.0 mg, 0.140 mmol). The resulting mixture was heated at overnight. After cooling to RT, the mixture was concentrated under reduced pressure and diluted with DCM. The organic portion was washed with water and dried by passing through a phase separating column. The solvent was removed under reduced pressure and purification of the crude product by chromatography on silica eluting with 0-60% EtOAc in iso-hexane afforded the titled compound;
