Formic Acid → 2,2-Bis(4-fluorophenyl)acetic acid

Participants

Reaction Steps

To 4,4′-difluorobenzhydrol (10.0 g, 45.4 mmol, 1 equiv) in H2SO4 (37 M; 200 mL, 7.4 mol, 160 equiv) in an ice bath was added formic acid (20 mL, 24 g, 0.53 mol, 12 equiv) with no stirring. After a few seconds, carbon monoxide evolution was observed. The reaction was allowed to stand without stirring for 3.5 h. The reaction mixture was carefully poured into H2O (1000 mL) (highly exothermic). The aqueous mixture was extracted with EtOAc (1×250 mL). The organic layer was dried (anh. Na2SO4) and rotary evaporated (75° C.) to yield 11.7 g of an orange oil. This oil was dissolved in Et2O (100 mL) and extracted with 2 M NaOH (1×50 mL). The aqueous layer was then acidified with 12 M HCl (8 mL) and extracted with EtOAc (1×50 mL). The organic layer was dried (anh. Na2SO4), rotary evaporated (75° C.), and put under high vacuum for 16 h. This provided 6.15 g (54.6%) of product as a yellow, crystalline solid.

Provenance & Evidence