methyl (E)-3-(1H-indol-7-yl)prop-2-enoate

Conditions: temp:70.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 7-Bromoindole (5.0 g, 25.5 mmol), methyl acrylate (4.6 ml, 51.1 mmol), triphenylphosphine (0.55 g, 2.10 mmol), N,N-diisopropylethylamine (5.8 ml, 42.3 mmol), and palladium (II) acetate (0.25 g, 1.11 mmol) were added to N,N-dimethylformamide (50 ml), and the mixture was stirred at 70° C. for 18 hours under a stream of nitrogen. After cooling to room temperature, methyl acrylate (4.6 ml, 51.1 mmol), triphenylphosphine (0.55 g, 2.10 mmol), and palladium (II) acetate (0.25 g, 1.11 mmol) were added to the reaction mixture, and the mixture was stirred at 75° C. for 47 hours under a stream of nitrogen. After cooling to room temperature, methyl acrylate (7.0 ml, 77.7 mmol), triphenylphosphine (0.88 g, 3.36 mmol), and palladium (II) acetate (0.40 g, 1.78 mmol) were added to the reaction mixture, and the mixture was stirred at 100° C. for 95 hours under a stream of nitrogen. After cooling to room temperature, the reaction mixture was concentrated under reduced pressure. To the obtained residue, a hexane/ethyl acetate mixed solution (1:1, 300 ml) was added, and the organic layer was washed with water. The obtained aqueous layer was subjected to extraction with a hexane/ethyl acetate (1:1) mixed solution, and the combined organic layer was washed with saturated saline. The obtained organic layer was dried over anhydrous magnesium sulfate and then concentrated under reduced pressure. The obtained residue was purified by silica gel chromatography (eluent; hexane:ethyl acetate=6:1) to obtain 2 (E)-methyl 3-(1H-indol-7-yl)acrylate (3.46 g, 67%) as a pale yellow-brown solid. ESI-MS: m/z 202 [M+H]+. 1H-NMR (CDCl3) δ: 3.85 (3H, s), 6.52 (1H, d, J=16.0 Hz), 6.62 (1H, dd, J=2.9, 2.0 Hz), 7.16 (1H, t, J=7.6 Hz), 7.28 (1H, t, J=2.9 Hz), 7.43 (1H, d, J=7.6 Hz), 7.71 (1H, d, J=7.6 Hz), 8.04 (1H, d, J=16.0 Hz), 8.59 (1H, br s). After cooling to room temperature the mixture was stirred at 75° C. for 47 hours under a stream of nitrogen After cooling to room temperature the mixture was stirred at 100° C. for 95 hours under a stream of nitrogen After cooling to room temperature the reaction mixture was concentrated under reduced pressure To the obtained residue, a hexane/ethyl acetate mixed solution (1:1, 300 ml) was added the organic layer was washed with water The obtained aqueous layer was subjected to extraction with a hexane/ethyl acetate (1:1) mixed solution the combined organic layer was washed with saturated saline The obtained organic layer was dried over anhydrous magnesium sulfate concentrated under reduced pressure The obtained residue was purified by silica gel chromatography (eluent; hexane:ethyl acetate=6:1)