A convenient method to reduce hydroxyl-substituted aromatic carboxylic acid with NaBH4/Me2SO4/B(OMe)3

The reduction of hydroxyl-substituted aromatic carboxylic acid with NaBH4/Me2SO4/B(OMe)3 is described. Borane is generated by the reaction of NaBH4 with Me2SO4 in THF, which is as efficient as the commercial one. B(OMe)3 has been successfully applied to increase the reactivity and selectivity of this reaction. The optimum ratio of borane/B(OMe)3/acid is studied, and a variety of hydroxyl-substituted aromatic acids are reduced in good yields.