Tetrahydrofuran → 5-(2-Hydroxy-ethyl)-indole-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a solution of 5-vinyl-indole-1-carboxylic acid tert-butyl ester (4.5 g, 18.5 mmol, 1.0 eq.) in THF (46 mL) at 0° C. was added 9-BBN (0.5 M in THF, 87 mL, 2.4 eq.) over 10 min. The resulting reaction mixture was stirred for 2.5 h and diluted with THF (150 mL) and water (150 mL) while keeping the temperature at 0° C. Then NaBO3. 4H2O (44 g) was introduced and resulting reaction mixture was stirred and warmed to room temperature and stirred. The reaction mixture was diluted with methylene chloride (100 mL) and the separated aqueous layer was extracted 3×100 mL methylene chloride. The combined organic layers were dried over sodium sulfate, filtered and concentrated. The residue was purified by chromatography (methylene chloride to 5% acetone/methylene chloride) to give 5-(2-hydroxy-ethyl)-indole-1-carboxylic acid tert-butyl ester (3.82 g, 76%) or similarly 6-(2-hydroxy-ethyl)-indole-1-carboxylic acid tert-butyl ester.

Provenance & Evidence