Allyl bromide → Methyl 6-allyl-2-bromo-4-(3,4-dichlorophenyl)-7-oxo-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-5-carboxylate

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Reaction Steps

To a solution of methyl 2-bromo-4-(3,4-dichlorophenyl)-7-oxo-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-5-carboxylate (0.320 g, 0.735 mmol) in tetrahydrofuran (19 mL, 230 mmol) was added lithium bis(trimethylsilyl)amide (1.103 mmol, 1.103 mmol) in tetrahydrofuran (0.956 mL, 11.8 mmol) at −78° C. under argon. The mixture was stirred for 30 min before allyl bromide (1.27 mL, 14.7 mmol) was added. The reaction mixture was warmed to rt and stirred for 3 hr. The mixture was quenched by addition of sat. NH4Cl and then extracted with EtOAc. The organic layer was separated, dried, and concentrated in vacuo. The residue was purified by silica gel chromatography to afford methyl 6-allyl-2-bromo-4-(3,4-dichlorophenyl)-7-oxo-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-5-carboxylate, the first fraction, as a white solid (58 mg, 16%). LCMS: (AA) ES−: 474, 476, 1H NMR (400 MHz, CDCl3) δ 7.36 (dd, J=8.3, 4.1 Hz, 1H), 7.17 (d, J=2.1 Hz, 1H), 6.87 (dt, J=9.8, 4.9 Hz, 1H), 6.79 (s, 1H), 5.36-5.23 (m, 1H), 5.03-4.93 (m, 2H), 4.71 (ddt, J=15.2, 5.2, 1.4 Hz, 1H), 4.63 (s, 1H), 4.18 (d, J=1.5 Hz, 1H), 3.74 (s, 3H), 3.46-3.35 (m, 1H).

Provenance & Evidence