Triisopropyl borate → (6-Methoxy-1-benzothiophen-2-yl)boronic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of 6-methoxybenzo[b]thiophene (Graham, S. L., et al. J. Med. Chem. 1989, 32,2548-2554) (18.13 g, 0.111 mol) in 150 mL of anhydrous THF at −60° C. was added n-BuLi (76.2 mL., 0.122 mol. 1.6 M solution in hexanes), dropwise via syringe. After stirring for 30 min, triisopropyl borate (28.2 ml. 0.122 mol) was introduced via syringe. The resulting mixture was allowed to gradually warm to 9° C. and then partitioned between 1.0 N HCl and EtOAc (300 mL each). The layers were separated, and the organicphase was dried over Na2SO4. Concentration in vacuo produced a white solit that was triturated from Et2O/hexanes. Filtration provided 16.4 g (71%) of 6-methoxybenzo[b]thiophene-2-boronic acid as a white solid.

Provenance & Evidence