Tetrahydrofuran → 2,4-Difluoro-5-sulfobenzoic acid
Reaction equation
[BH4-].[Na+].Cl[S:4]([C:7]1[C:8]([F:17])=[CH:9][C:10]([F:16])=[C:11]([CH:15]=1)[C:12]([OH:14])=[O:13])(=[O:6])=[O:5].C1C[O:21]CC1>>[F:16][C:10]1[CH:9]=[C:8]([F:17])[C:7]([S:4]([OH:21])(=[O:6])=[O:5])=[CH:15][C:11]=1[C:12]([OH:14])=[O:13]Participants
4
Procedure
Sodium borohydride (0.59 g, 15.6 mmol, 8 equiv) was added portionwise to a solution of 5-(chlorosulfonyl)-2,4-difluorobenzoic acid 885-6a (0.5 g, 1.9 mmol, 1 equiv) in 10 mL THF at 0° C. The reaction was stirred at this temperature for 1 h and then concentrated down and the residue acidified to pH 2 with 5N HCl. The precipitate was removed by filtration and the liquid concentrated down to provide 2,4-difluoro-5-sulfobenzoic acid 885-6b as a white solid (433 mg, 100% yield)