Tributyltin Chloride → 3-((5-Bromo-2-methoxyphenyl)(tert-butyldimethylsilyloxy)methyl)-2,6-difluoro-5-(tributylstannyl)pyridine

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Reaction Steps

DIPA (1.2 mL, 8.49 mmol) (freshly distilled) was dissolved in dry THF (40 mL) under nitrogen and cooled in a dry ice bath to −78°. N-butyllithium solution (2.5 m in hexanes, 3.0 mL, 7.50 mmol) was added and the solution stirred for a few minutes. A solution of 3-((5-bromo-2-methoxyphenyl)(tert-butyldimethylsilyloxy)methyl)-2,6-difluoropyridine (3.20 g, 7.20 mmol) in dry THF (20 mL) was added dropwise via an addition funnel and the solution stirred for 1 hour. Tributyltin chloride (2.0 mL, 7.37 mmol) was added to the pale yellow solution and it was stirred for 10 minutes. The reaction was quenched by addition of saturated ammonium chloride (10 mL). Water (100 mL) and diethyl ether (200 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 (2-15% diethyl ether in hexane gradient) gave 3-((5-bromo-2-methoxyphenyl)(tert-butyldimethylsilyloxy)methyl)-2,6-difluoro-5-(tributylstannyl)pyridine.

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