5-Bromo-2-fluorobenzaldehyde → 2-fluoro-3-(methoxymethoxy)-6-(tetrahydro-2H-pyran-4-yl)pyridine

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Reaction Steps

4-Bromo-2-fluoro-3-(methoxymethoxy)-6-(tetrahydro-2H-pyran-4-yl)pyridine (1.62 g, 5.06 mmol) was dissolved in dry tetrahydrofuran (50 mL) under nitrogen and cooled in a dry ice bath. Butyllithium solution (2.5 M in hexanes, 2.2 mL, 5.50 mmol) was added and the reaction stirred for 5 min. A solution of 5-bromo-2-fluorobenzaldehyde (1.03 g, 5.06 mmol) in dry THF (10 mL) was added and the reaction stirred for 35 min then quenched by addition of saturated ammonium chloride (20 mL). Water (100 mL) and EtOAc (100 mL) were added and the phases mixed and separated. The organic was dried with magnesium sulfate and evaporated to dryness under reduced pressure. Purification using silica chromatography (hexane to EtOAc gradient) gave recovered starting material (0.30 g, 18%), debrominated 2-fluoro-3-(methoxymethoxy)-6-(tetrahydro-2H-pyran-4-yl)pyridine (0.15 g, 0.61 mmol, 12.0% yield) and the desired (5-bromo-2-fluorophenyl)(2-fluoro-3-(methoxymethoxy)-6-(tetrahydro-2H-pyran-4-yl)pyridin-4-yl)methanol (0.85 g, 1.90 mmol)

Provenance & Evidence