Boron tribromide → 5,6-Dihydroxyisobenzofuran-1(3H)-one

Participants

Reaction Steps

A solution of compound 24 (7.00 g, 36.1 mmol) in CH2Cl2 (150 mL) was cooled to −78° C. and BBr3 (8.52 mL, 90.2 mmol) was added at the same temperature. Stirring was continued at −78° C. for 30 min, and the reaction mixture was brought to room temperature and stirred for 16 h. The reaction mixture was quenched with MeOH at 0° C. and the solvent was removed. The residue was portioned between water (100 mL) and EtOAc (200 mL); the EtOAc layer was separated. The aqueous layer was extracted with EtOAc (3×200 mL). The combined organic layer was concentrated and the residue was purified by column chromatography (silica gel, 40-60% EtOAc in hexanes) to afford compound 25 (5.00 g, 83%) as an off-white solid: 1H NMR (400 MHz, DMSO-d6) δ 10.18 (br s, 1H), 9.65 (br s, 1H), 7.06 (s, 1H), 6.92 (s, 1H), 5.16 (s, 2H).

Provenance & Evidence