Diisobutylaluminum hydride → 5-Bromo-3-fluoropyridine-2-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

A solution of 3-fluoro-5-bromopyridine carboxylic acid methoxymethylamide (630 mg, 2.4 mmol) in dry THF (12 mL) was cooled to −50° C. and DIBAL (1M in THF; 2.8 mL, 2.8 mmol) was added over 15 min maintaining the temperature below −50° C. The reaction was stirred at −50° C. for 2 h. An additional portion of and DIBAL (1M in THF; 0.25 mL, 0.25 mmol) was added and the reaction mixture was allowed to warm slowly to −10° C. over 2 h. The reaction was quenched by the dropwise addition of water (5 mL) and the THF was removed in vacuo and a dilute solution of Rochelle's salt was added. The aqueous was extracted with EtOAc (×3) and the combined organics dried (MgSO4) and concentrated in vacuo. Purification by column chromatography (gradient: 10%-90% EtOAc in petroleum ether 40-60c) yielded 3-fluoro-5-bromopyridine-2-carbaldehyde as a yellow solid.

Provenance & Evidence