Br[C:2]1[CH:10]=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[CH:4][C:3]=1[F:11].CC1(C)C(C)(C)OB([C:20]2[O:24][C:23]([Si](C(C)C)(C(C)C)C(C)C)=[N:22][CH:21]=2)O1.C([O-])([O-])=O.[Na+].[Na+]>CN(C)C=O.Cl[Pd]Cl>[F:11][C:3]1[CH:4]=[C:5]([CH:9]=[CH:10][C:2]=1[C:20]1[O:24][CH:23]=[N:22][CH:21]=1)[C:6]([OH:8])=[O:7]
A mixture of 4-bromo-3-fluoro-benzoic acid (1.00 g), 5-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-2-triisopropylsilanyl-oxazole (1.90 g), PdCl2 [1,1′-bis(diphenylphosphino)-ferrocene]*CH2Cl2 complex (400 mg), and aqueous Na2CO3 solution (2 M; 5.70 mL) in N,N-dimethylformamide (6 mL) is stirred overnight at 80° C. under an argon atmosphere. After cooling to room temperature the reaction mixture is concentrated in vacuo and water is added. The resulting mixture is acidified with hydrochloric acid (4 M; 6 mL) and extracted with ethyl acetate. The combined extracts are washed with brine, dried over MgSO4 and concentrated in vacuo. The residue is triturated with diethyl ether, filtered off and dried to give the title product. LC (method 1): tR=0.87 min; Mass spectrum (ESI+): m/z=208 [M+H]+.
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