Triisopropyl borate → (2-tert-Butyl-1H-pyrrolo[2,3-b]pyridin-4-yl)boronic acid

Participants

Reaction Steps

4-Bromo-2-(1,1-dimethylethyl)-1H-pyrrolo[2,3-b]pyridine (430 mg, 1.7 mmol) was dissolved in anhydrous THF (12 ml) under nitrogen and degassed (nitrogen/vacuum 3 times). Sodium hydride (60% dispersion in mineral oil) (88 mg, 2.2 mmol) was added and the reaction stirred at room temperature for 50 mins. The reaction was then cooled to −78° C., further degassed as before and 1.5M nbutyl lithium in hexanes (1.6 ml, 2.4 mmol) was added dropwise over 5 mins. The reaction was stirred for 45 mins then tri-isopropyl borate (1.2 ml) was added. The reaction was stirred for a further hour before warming to room temperature. Saturated ammonium chloride (aq) (20 ml) was added and the reaction was extracted with DCM (2×25 ml). The combined organics were washed with water (50 ml), passed through a hydrophobic frit and concentrated. The residue was dissolved in DCM:MeOH (1:1, v/v) and loaded onto an aminopropyl cartridge (10 g). The cartridge was washed with DCM:MeOH (1:1, v/v) and eluted with 2M ammonia in MeOH, which was concentrated to give title compound, 164 mg.

Provenance & Evidence