Formaldehyde → 5-Bromo-7-fluoroisobenzofuran-1(3H)-one

反応式

[Li][CH2:2]CCC.Br[C:7]1[CH:15]=[C:14]([Br:16])[CH:13]=[C:12]([F:17])[C:8]=1[C:9]([OH:11])=[O:10].C=O>CCOC(C)=O>[Br:16][C:14]1[CH:13]=[C:12]([F:17])[C:8]2[C:9](=[O:10])[O:11][CH2:2][C:7]=2[CH:15]=1

参加物

実験手順

A solution of n-BuLi (36.7 mL, 91.6 mmol) was added dropwise to a solution of 2,4-dibromo-6-fluorobenzoic acid (13.0 g, 43.6 mmol, in 200 mL of THF) at −70° C. The resulting solution was stirred for 15 minutes before CH2O gas (generated by heating 5.1 g of Para formaldehyde to 200° C.) was bubbled into the mixture at −70° C. The suspension was stirred for 1 hour then warmed to room temperature and stirred for another 2 hours. HCl gas was bubbled into the suspension for 15 minutes to give a clear solution. The mixture was diluted with 1 L of EtOAc and washed subsequently with water, saturated Na2CO3 and brine, then dried over anhydrous Na2SO4 and concentrated. The residue was purified by column chromatography (PE:EtOAc=5:1) to give 5-bromo-7-fluoro-2-benzofuran-1(3H)-one as white solid.