Sodium cyanoborohydride → 3-benzyl-7-bromo-1H-indole-2-carboxylic acid ethyl ester

Participants

Reaction Steps

To a solution of 3-benzoyl-7-bromo-1H-indole-2-carboxylic acid ethyl ester (2.4 g, 6.45 mmol) in 1,2-dichloroethane (80 ml) was added NaBH3CN (3.24 g, 51.6 mmol) and ZnI2 (6.18 g, 19.4 mmol). After stirring at room temperature for 30 minutes, the reaction mixture was poured into a mixture of EtOAc/H2O. The organic layer was separated and washed with water and brine. After drying over MgSO4, the organic fraction was concentrated in vacuo and the resulting residue was purified by flash chromatography to give 3-benzyl-7-bromo-1H-indole-2-carboxylic acid ethyl ester as yellow solid (696 mg, 30%). 1H NMR (CDCl3, 300 MHz) δ: 1.39 (t, 3H, J=7.13 Hz), 4.43 (q, 2H, J=7.13 Hz), 4.49 (s, 2H), 6.98 (t, 1H, J=7.8 Hz), 7.22 (m, 5H), 7.46 (d, 1H, J=7.60 Hz), 7.54 (d, 1H, J=8.10 Hz).

Provenance & Evidence