6-bromo-2-methyl-1-benzofuran

Conditions: temp:190.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 49 (21 mmol) in N, N-diethylaniline (30 mL), cesium fluoride (11 mmol) was added and the mixture was heated at 190° C. for 24 h. After cooling, the suspension was diluted with ethyl acetate (100 mL) and washed with dil HCl (3×50 mL). The combined organic layer was washed with brine, dried over anhydrous Na2SO4 and concentrated by rotary evaporation and purified column chromatography to give 4-bromo-2-methylbenzofuran (46g, 87%) and 6-bromo-2-methylbenzofuran (13%). The resulting mixture was purified by reverse phase HPLC using 10:1 acetonitrile: water with 0.1% TFA (B) for 22 min followed by 3 min at 100% B, to give compound 46g (26%). After cooling washed with dil HCl (3×50 mL) The combined organic layer was washed with brine dried over anhydrous Na2SO4 concentrated by rotary evaporation purified column chromatography

Conditions: temp:190.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 49 (21 mmol) in N, N-diethylaniline (30 mL), cesium fluoride (11 mmol) was added and the mixture was heated at 190° C. for 24 h. After cooling, the suspension was diluted with ethyl acetate (100 mL) and washed with dil HCl (3×50 mL). The combined organic layer was washed with brine, dried over anhydrous Na2SO4 and concentrated by rotary evaporation and purified column chromatography to give 4-bromo-2-methylbenzofuran (46g, 87%) and 6-bromo-2-methylbenzofuran (13%). The resulting mixture was purified by reverse phase HPLC using 10:1 acetonitrile: water with 0.1% TFA (B) for 22 min followed by 3 min at 100% B, to give compound 46g (26%). After cooling washed with dil HCl (3×50 mL) The combined organic layer was washed with brine dried over anhydrous Na2SO4 concentrated by rotary evaporation purified column chromatography