7-bromo-3-chloro-1-fluoro-5H-chromeno[2,3-c]pyridin-5-one → tert-butyl 2-(7-bromo-3-chloro-1-fluoro-5-hydroxy-5H-chromeno[2,3-c]pyridin-5-yl)acetate

Participants

Reaction Conditions

Reaction Steps

To a solution of (2-tert-butoxy-2-oxoethyl)zinc(II) chloride (0.5M in Et2O; 670 ml, 335 mmol) at 0° C. was added drop wise a solution of 7-bromo-3-chloro-1-fluoro-5H-chromeno[2,3-c]pyridin-5-one (55 g, 167 mmol) in THF (30 mL). The resulting reaction mixture was stirred at 0° C. for 1 h. The reaction mixture was quenched with aqueous, saturated NH4Cl solution and extracted with EtOAc. The organic extracts were dried over Na2SO4 and concentrated under reduced pressure to afford tert-butyl 2-(7-bromo-3-chloro-1-fluoro-5-hydroxy-5H-chromeno[2,3-c]pyridin-5-yl)acetate (66.0 g, 148 mmol, 89% yield) as a yellow solid.

Provenance & Evidence