Triisopropyl borate → HCID 66717113, compound

Participants

Reaction Conditions

Reaction Steps

A stirred mixture of 3-bromo-2-methoxy-5-methylthiophene (Step B, 296 mg, 1.43 mmol) and triisopropyl borate (396 μL, 2.15 mmol) in toluene/THF (2.3/0.6 mL) was cooled to −70° C. under an atmosphere of N2. n-Butyl lithium (2.0M in pentane, 1.07 mL, 2.15 mmol) was added dropwise via a syringe pump over 1 h. The reaction stirred at −70° C. for 40 min more and was quenched with 2N HCl (2 mL) at −20° C. The reaction was partitioned between EtOAc (15 mL) and H2O (15 mL). The aqueous layer was extracted with EtOAc (10 mL); the combined organic layers were washed with brine (15 mL), dried (Na2SO4), filtered, and concentrated in vacuo to afford (2-methoxy-5-methyl-3-thienyl)boronic acid as a yellow oil. This material was used without further purification.

Provenance & Evidence