Br[C:2]1[CH:3]=[C:4]([CH:9]=[C:10]([Br:13])[C:11]=1[CH3:12])[C:5]([O:7][CH3:8])=[O:6].CC1(C)C(C)(C)OB(/[CH:22]=[CH:23]/[CH2:24][O:25][CH3:26])O1.C([O-])([O-])=O.[Na+].[Na+]>CN(C=O)C.O>[Br:13][C:10]1[CH:9]=[C:4]([CH:3]=[C:2](/[CH:22]=[CH:23]/[CH2:24][O:25][CH3:26])[C:11]=1[CH3:12])[C:5]([O:7][CH3:8])=[O:6]
To a solution of methyl 3,5-dibromo-4-methylbenzoate (1 eq.) and 4,4,5,5-tetramethyl-2-[(1E)-3-(methyloxy)-1-propen-1-yl]-1,3,2-dioxaborolane (1.1 eq.) in DMF (0.1 M) was added trans-bis(triphenylphosphine) palladium(II) bromide (0.02 eq.). The vessel was repeatedly evacuated and back-filled with nitrogen. Finally, 2 M aq. Na2CO3 (3 eq.) was added and the resulting mixture was heated at 100° C. for 2 h. The now black suspension was cooled to RT, diluted with water and extracted with ether. The combined organic extracts were washed further with water and brine, dried over Na2SO4, filtered and the filtrate concentrated in vacuo. Purification of the crude product by way of flash chromatography (SiO2, 9:1 (v/v) Hex:EtOAc→→1:1 (v/v) Hex:EtOAc) afforded the title compound as a colorless oil.
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