反应详情

To a flask charged with (3-bromo-2-methoxyphenyl)methanol (3.0 g, 14 mmol, 1.0 eq) was added thallic trifluoroacetate (10.0 g, 18.4 mmol, 1.3 eq). To above mixture was added trifluoroacetic acid (25 mL). The reaction was stirred at r.t. for 16 hr, then concentrated. The excess TFA was removed using high vacuum pump. To the residue was added palladium chloride (245 mg, 1.38 mmol, 0.1 eq), magnesium oxide (1.10 g, 27.6 mmol, 2.0 eq) and methanol (35 mL). The reaction was flushed with carbon monoxide three times and stirred under CO at r.t. for 2 hr. To this solution was added ethyl acetate. The mixture was filtered through a pad of celite and washed with EtOAc. The filtrate was concentrated and loaded on silica gel column. The fractions containing 5-bromo-4-methoxy-2-benzofuran-1(3H)-one were concentrated. 1H NMR (500 MHz, CDCl3, δ in ppm): 7.72 (1H, aromatic, d, J=8.0 Hz), 7.49 (1H, aromatic, d, J=8.0 Hz), 5.44 (2H, s, CH2 lactone), 4.00 (3H, s, Me). LC-MS (IE, m/z): 244.88 [M+1]+; tR=2.67 min.

1. concentrationconcentrated
2. customThe excess TFA was removed
3. customThe reaction was flushed with carbon monoxide three times
4. stirringstirred under CO at r.t. for 2 hr
5. additionTo this solution was added ethyl acetate
6. filtrationThe mixture was filtered through a pad of celite
7. washwashed with EtOAc
8. concentrationThe filtrate was concentrated
9. additionThe fractions containing 5-bromo-4-methoxy-2-benzofuran-1(3H)-one
10. concentrationwere concentrated