C[Mg+].[Br-].CCO[CH2:7][CH3:8].ClC1[C:11]2[N:12]([CH:16]=[C:17]([C:19]3[CH:24]=[CH:23][C:22]([F:25])=[CH:21][CH:20]=3)[N:18]=2)[CH:13]=[CH:14][N:15]=1.C1COCC1>CN1C(=O)CCC1>[F:25][C:22]1[CH:21]=[CH:20][C:19]([C:17]2[N:18]=[C:11]3[C:7]([CH3:8])=[N:15][CH:14]=[CH:13][N:12]3[CH:16]=2)=[CH:24][CH:23]=1A solution of 3M MeMgBr in Et2O (16.1 mL, 48.3 mmol) was added drop-wise to a mixture of 8-chloro-2-(4-fluorophenyl)-imidazo[1,2-a]pyrazine (10.0 g, 40.6 mmol), ferric acetylacetonate (0.71 g, 2.0 mmol), THF (240 mL), and NMP (23 mL) at about 0° C. The mixture was warmed to ambient temperature over about 1 hour. After about 1 hour, the reaction was cooled to about 0° C. and treated with additional 3M MeMgBr in Et2O (4 mL, 12 mmol). The mixture was allowed to warm to ambient temperature over about 1 h. After about an additional 1 h, the mixture was quenched with water and extracted with EtOAc. The organic layers were combined and dried with Na2SO4. After concentration, the crude material was purified by FCC on silica gel using EtOAc as an eluent to afford the expected product as an off-white solid (9.6 g, 100%): LC/MS (Table 1, Method b) Rt=1.8 min; MS m/z: 228.2 (M+H)+.
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