Ethyl 1H-indole-3-acetate → tert-butyl 2-bromo-3-(2-ethoxy-2-oxoethyl)-1H-indole-1-carboxylate

Participants

Reaction Steps

Ethyl 2-(1H-indol-3-yl)acetate (15 g, 73.9 mmol) was dissolved in DCM (750 mL). At ambient temperature, NBS (13.15 g, 73.9 mmol) was added to the reaction mixture in 5 portions approximately 2 minutes apart. After the last addition of NBS, iPr2NEt (28 mL, 162 mmol) was added slowly to the reaction mixture and stirred for 5 minutes. Boc2O (33.8 g, 155 mmol) was added followed by DMAP (900 mg). After stirring at 16 h, the reaction was partitioned between DCM and H2O. The organics were washed with aqueous 1N HCl and dried over sodium sulfate. After removal of solvent, the crude product was purified by silica gel chromatography to provide tert-butyl 2-bromo-3-(2-ethoxy-2-oxoethyl)-1H-indole-1-carboxylate (16.3 g, 58%). MS (m/z) 382 [M+H]+.

Provenance & Evidence