[O:1]1[C:5]2[CH:6]=[CH:7][C:8]([C:10]3[O:14][CH:13]=[N:12][CH:11]=3)=[CH:9][C:4]=2[O:3][CH2:2]1.C[Si]([N-][Si](C)(C)C)(C)C.[Li+].[Br:25]NC(=O)CCC(N)=O.[OH-].[Na+]>CN(C)C=O.C(Cl)Cl>[O:1]1[C:5]2[CH:6]=[CH:7][C:8]([C:10]3[O:14][CH:13]=[N:12][C:11]=3[Br:25])=[CH:9][C:4]=2[O:3][CH2:2]1To a −78° C. solution of 5-benzo[1,3]dioxol-5-yl-oxazole (670 mg, 3.54 mmol) in dimethylformamide (5 mL) was slowly added lithium bis(trimethylsilyl)amide(3.54 mL, 1 M in THF, 3.54 mmol, 1 equiv). The reaction mixture was stirred under nitrogen atmosphere for 1 hour at −78° C., and then treated slowly with a solution of N-bromosuccinamide (630 mg, 3.54 mmol, 1 equiv) in dimethylformamide (2 mL). The resulting reaction mixture was stirred at −78° C. for 1 hour, warmed to ambient temperature and poured into a mixture methylene chloride and 1 N aqueous sodium hydroxide. The aqueous layer was exctracted with methylene chloride, and the combined organics were washed with 1 N aqueous sodium hydroxide and brine, then dried over magnesium sulfate and concentrated in vacuo to provide 5-benzo[1,3]dioxol-5-yl-4-bromo-oxazole (853 mg, 90%).
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