Potassium Carbonate → ethyl 8-carbamoyl-5-(2,6-difluorophenyl)-2,3,4,9-tetrahydro-1H-carbazole-2-carboxylate

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Reaction Steps

A mixture of ethyl 5-bromo-8-carbamoyl-2,3,4,9-tetrahydro-1H-carbazole-2-carboxylate (Intermediate 47-1, 20 mg, 0.055 mmol), 2,6-difluorophenylboronic acid (17.3 mg, 0.110 mmol), dicyclohexyl(2′,6′-dimethoxybiphenyl-2-yl)phosphine (4.5 mg, 11.0 mmol), potassium carbonate (15.1 mg, 0.110 mmol) and tris(dibenzylideneacetone)dipalladium (5.0 mg, 0.005 mmol) in THF (2 mL) was purged with nitrogen for 2 min, then was heated in a sealed tube overnight. The mixture was filtered and concentrated, and the residue was purified by preparative HPLC. The appropriate effluent fractions were made basic with 1 M aqueous sodium hydroxide and extracted twice with DCM. The combined organic phases were washed with water, dried and concentrated to provide ethyl 8-carbamoyl-5-(2,6-difluorophenyl)-2,3,4,9-tetrahydro-1H-carbazole-2-carboxylate as a light yellow solid (10 mg, 44%). 1H NMR (400 MHz, chloroform-d) δ 10.10 (1H, br. s.), 7.31-7.44 (2H, m), 6.95-7.06 (3H, m), 4.10-4.22 (2H, m), 2.96-3.12 (2H, m), 2.80 (1H, dddd, J=17.52, 5.99, 3.08, 2.86 Hz), 2.27-2.41 (1H, m), 2.15-2.27 (1H, m), 2.04-2.14 (1H, m), 1.69-1.85 (1H, m), 1.26 (3H, t, J=7.25 Hz). Mass spectrum m/z 399.1 (M+H)+.

Provenance & Evidence