1-(Toluene-4-sulfonyl)-3-tributylstannanyl-1H-indole-5-carbonitrile (5.60 g, 9.56 mMol), 2-trifluoromethanesulfonyloxy-cyclopent-1-enecarboxylic acid ethyl ester (2.75 g, 9.56 mMol), triphenyl arsine (0.29 g, 0.96 mMol) and tris(dibenzylidenacetone)dipalladium(0) (0.44 g, 0.48 mMol) were dissolved in DMF and degassed for 5 min with a stream of nitrogen. The reaction was heated under nitrogen at 60° C. for 5 min. The reaction was poured into brine (500 mL) and extracted with ethyl acetate (2×100 mL). The organics were mixed with saturated aqueous potassium fluoride (100 mL) and the resulting solids were removed by filtration through celite. The layers of the filtrate were separated and the organic layer was dried with magnesium sulfate and evaporated in vacuo. The solid product was recrystallized from hot ethyl acetate/hexanes to provide the product as a white solid (3.04 g, 73%). 1H NMR (400 MHz, CDCl3) δ 8.05 (1H, d, J=8.7 Hz), 7.87 (1H, s), 7.79 (2H, d, J=8.5 Hz), 7.71 (1H, d, J=1.2 Hz), 7.53 (1H, dd, J=8.8, 1.5 Hz), 7.27 (2H, m), 4.01 (2H, q, J=6.9 Hz), 2.86 (4H, m), 2.36 (3H, s), 2.03 (2H, pentet, J=7.7 Hz), 0.95 (3H, t, J=7.1 Hz); MS m/e 457.0 (M+Na).
