Potassium Carbonate → 1h-Indole-5-carboxylic acid,3-methyl-2-phenyl-,ethyl ester

Participants

Reaction Conditions

Reaction Steps

Adapting the procedure of H.-C. Zhang (Tet. Lett. 1997, 38, 2439) ethyl 4-amino-3-iodobenzoate (from example 10, 0.500 g, 1.72 mmol) was dissolved in DMF (5 mL) and LiCl (0.073 g, 1.72 mmol, 1 equivalent), PPh3 (0.090 g, 0.34 mmol, 0.2 equivalent), K2CO3 (1.188 g, 8.6 mmol, 5 equivalents) and phenylpropyne (0.645 mL, 5.76 mmol, 3 equivalents) were added. The solution was degassed by purging with argon for 1 h and palladium acetate (0.039 g, 0.17 mmol, 0.1 equivalent) was added. The mixture was stirred at 80° C. under argon for 20 h. The reaction mixture was diluted with water (25 mL) and extracted with EtOAc (50 mL). The extract was washed with brine (3×25 mL) and dried (MgSO4). Concentration under reduced pressure and purification by flash chromatography with 10-15% EtOAc-hexane gave the desired 2-phenyl-3-methyl indole (0.275 g, least polar component) and the 3-phenyl-2-methyl isomer (0.109 g, more polar component).

Provenance & Evidence