[F:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[C:9]([N:14]3[CH2:19][CH2:18][NH:17][CH2:16][CH2:15]3)=[N:10][CH:11]=[CH:12][N:13]=2)=[CH:4][CH:3]=1.[C:20]([O:24][C:25](=[O:31])[N:26]([CH3:30])[CH2:27][CH:28]=O)([CH3:23])([CH3:22])[CH3:21].C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+]>ClCCCl>[C:20]([O:24][C:25](=[O:31])[N:26]([CH2:27][CH2:28][N:17]1[CH2:16][CH2:15][N:14]([C:9]2[C:8]([C:5]3[CH:6]=[CH:7][C:2]([F:1])=[CH:3][CH:4]=3)=[N:13][CH:12]=[CH:11][N:10]=2)[CH2:19][CH2:18]1)[CH3:30])([CH3:23])([CH3:22])[CH3:21]Dissolve 3′-(4-fluoro-phenyl)-3,4,5,6-tetrahydro-2H-[1,2′]bipyrazinyl (2.5 g, 9.7 mmol, 1 eq.) in 1,2 dichloroethane (20 mL). Add methyl-(2-oxo-ethyl)-carbamic acid tert-butyl ester (1.77 g, 10.19 mmol, 1.05 eq.). Add sodium triacetoxy-borohydride (3.10 g, 14.6 mmol, 1.5 eq.). Stir at room temperature for 18 hr. Partition the reaction mixture between aqueous saturated NaHCO3 and dichloromethane. Separate the layers. Extract the organic layer with dichloromethane (2×100 mL). Combine the organic layers, dry over anhydrous Na2SO4, filter and concentrate. Purify by normal phase chromatography with 30% EtOAc/hexane—100% EtOAc to afford the title preparation (3.8 g, 97% yield). MS (loop): m/z=416.3 [M+H].
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