(2-(Dimethylamino)ethyl)triphenylphosphonium bromide → 3-(3-dimethylaminopropenyl)-1H-indole-2-carboxylic acid ethyl ester

Participants

Reaction Steps

Butyllithium (1.1 equiv.) was added to a suspension of (2-dimethylaminoethyl)triphenylphosphonium bromide in THF (0.2 M) at 0° C. After stirring for 30 minutes, lithium diethylamine (1.1 equiv.) was added dropwise followed by the cold suspension of 3-formyl-1H-indole-2-carboxylic acid ethyl ester (3.96 g, 18.2 mmol) in THF. The resulting orange suspension was stirred for 18 hours. The reaction was then quenched with saturated ammonium chloride and extracted with 10% MeOH in DCM. The organic layer was washed with saturated sodium bicarbonate, dried and concentrated to give 3-(3-dimethylaminopropenyl)-1H-indole-2-carboxylic acid ethyl ester as a brownish-red waxy solid.

Provenance & Evidence