9-Bromo-9-borabicyclo(3.3.1)nonane → 7-bromo-2-fluoro-3-(tributylstannyl)-5H-chromeno[2,3-b]pyridin-5-one

Participants

Reaction Conditions

Reaction Steps

(5-Bromo-2-methoxyphenyl)(2,6-difluoro-5-(tributylstannyl)pyridin-3-yl)methanone (6.48 g, 10.50 mmol) was dissolved in DCM (60 mL) under nitrogen and cooled in a dry ice bath to −78° C. 9-Bromo-9-borabicyclo[3.3.1]nonane, (1 M in DCM, 11.02 mL, 11.02 mmol) was added dropwise over 5 minutes and the reaction stirred for another 5 minutes. The flask was removed from the cold bath and stirred at ambient temperature for 20 minutes then saturated sodium bicarbonate (50 mL) was added to quench. Water (200 mL) and dichloromethane (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 dichloromethane gradient) gave 7-bromo-2-fluoro-3-(tributylstannyl)-5H-chromeno[2,3-b]pyridin-5-one.

Provenance & Evidence