反应详情

To a solution of ethyl 2-(5-bromothiophen-2-yl)-2-hydroxyacetate (2.5 g, 9.43 mmol, 1.0 eq), DMAP (115 mg, 0.94 mmol, 0.1 eq) in dichloromethane (30 mL) was added TBDMSCl (2.85 g, 18.91 mmol, 2.0 eq) and triethylamine (5.0 mL, 35.97 mmol, 3.8 eq) at 0° C. After addition, the ice-water bath is removed and the mixture is allowed to reach room temperature overnight. The reaction mixture was diluted with ethyl acetate, washed (brine), dried (Na2SO4), filtered and concentrated to give a residue, which was purified by silica gel column chromatography (PE:EA=50:1) to produce ethyl 2-(5-bromothiophen-2-yl)-2-(tert-butyldimethylsilyloxy)acetate (2.5 g, 69.9%). 1H NMR (400 MHz, DMSO-d6): δ 0.03 (s, 3H), 0.07 (s, 3H), 0.85 (s, 9H), 1.16 (t, J=7.0 Hz, 3H), 4.09-4.15 (m, 2H), 5.56 (d, J=0.8 Hz, 1H), 6.91-6.92 (m, 1H), 7.08 (d, J=4.0 Hz, 1H).

1. additionAfter addition
2. customthe ice-water bath is removed
3. additionThe reaction mixture was diluted with ethyl acetate
4. washwashed (brine)
5. dry with materialdried (Na2SO4)
6. filtrationfiltered
7. concentrationconcentrated
8. customto give a residue, which
9. customwas purified by silica gel column chromatography (PE:EA=50:1)