3-Methyl-2-butanol → 4-(1,2-Dimethyl-propoxy)-1H-indole-2-carboxylic acid ethyl ester

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Reaction Steps

DEAD (5.3 ml, 34.1 mmol) is slowly added to a solution of 4-Hydroxy-1H-indole-2-carboxylic acid ethyl ester 79 (5 g, 24.36 mmol), triphenylphosphine (8.95 g, 34.1 mmol) and 3-Methyl-butan-2-ol (3.58 ml, 33.13 mmol) in 50 ml of THF, so that the temperature always remained below 30° C. Stirring is continued for 3 days and the solvent is then evaporated. The crude mixture is purified by chromatography on silicagel using first cyclohexane as eluent, then increasing amounts of EtOAc (from 5% to 50%).

Provenance & Evidence