C[Sn](Cl)(C)C.[Na].Br[C:8]1[CH:13]=[CH:12][C:11]([C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)=[CH:10][CH:9]=1.C[Sn](C)C.[I:24]I>COCCOC.CCOC(C)=O>[I:24][C:8]1[CH:13]=[CH:12][C:11]([C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)=[CH:10][CH:9]=1A solution of trimethyltin chloride (5.5 g, 27.60 mmoles) in 5 mL of DME was added to a stirred suspension of small cubes of metallic sodium (1.9 g, 82.64 mg atom) in 15 mL of DME under an argon stream in an ice bath. When the addition was complete, the mixture was stirred and chilled in an ice bath for 2 hrs. (the color changed to green). The mixture was cannulated into another dry and under argon round bottom flask to remove excess sodium and cooled to 0° C. A solution of 4-bromobiphenyl (5.4 g, 22.70 mmoles) in 14 mL of DME was added dropwise to the chilled NaSnMe3 solution. The resulting solution was stirred at room temperature overnight at which time TLC analysis showed complete reaction. Rf of the trimethyltin product=0.44 (silica, hexanes). The reaction mixture was then cooled in an ice bath and treated with iodine (6.6 g, 26.00 mmoles). After stirring at room temperature for 1.5 hrs, the mixture was diluted with EtOAc, washed with water, brine, dried over MgSO4, and the solvent removed at reduced pressure. The crude product was then purified by column chromatography with hexanes to afford 5.5 g (86% yield) of white solid.
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