Trimethyl borate → (2,4-Difluoro-5-methylphenyl)boronic acid

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Reaction Steps

To 94A (2.8 g, 11 mmol) in THF (50 mL) was added n-BuLi (1.6M in hexane, 8.9 mL) at −78° C. After 10 min stirring, trimethyl borate (2.5 mL) was introduced. The mixture was stirred from −78° C. to rt overnight. The reaction was quenched by 1N HCl and extracted with EtOAc. The organic layer was separated and washed with saturated Na2S2O3, brine and dried over MgSO4. Evaporation of solvent gave product 94B (1.66 g, 88% yield) as a white solid. 1H NMR (400 MHz, CDCl3) δ ppm 2.22 (s, 3H) 6.82 (t, J=9.23 Hz, 1H) 7.26 (t, J=7.69 Hz, 1H).

Provenance & Evidence