Methyl indole-3-carboxylate (5.107 g, 29.15 mmol, 1 eq.) was dissolved in dichloromethane (100 ml) and 4-(N,N-dimethylamino)pyridine (0.698 g, 5.713 mmol, 0.2 eq.), triethylamine (11.9 ml, 85.38 mmol, 3.0 eq.) was added to the solution. The mixture was then stirred for 30 minutes. Trimethylacetyl chloride (4.90 ml, 39.8 mmol, 1.4 eq.) was then added and the mixture was stirred overnight. The mixture was washed with deionized water (2 x 20 ml). The organic phase was then dried over magnesium sulfate and filtered. The solvent was removed under reduced pressure and the product was purified by column chromatography (1:8 ethyl acetate:hexane on SiO₂), giving white crystals (5.712 g, 76%).

R_f = 0.41 (SiO₂, 1:4 EtOAc-hexanes)

M.p. 108-109.5 °C

¹H NMR (500 MHz, CDCl₃) δ 8.48 (d, J = 8.3, 1H), 8.42 (s, 1H), 8.18-8.16 (m, 1H), 7.42-7.37 (m, 2H), 3.97 (s, 3H), 1.56 (s, 9H)

¹³C NMR (126 MHz, CDCl₃) δ 177.2, 164.5, 137.1, 131.4, 126.3, 125.8, 124.6, 121.2, 117.0, 112.8, 51.5, 41.6, 28.6

IR (film, cm^-1) 3054.5, 2986.6, 2953.0, 1706.4, 1583.5, 1559.2, 1478.1, 1448.7, 1382.2, 1352.2, 1319.1, 1265.4, 1204.1, 1151.8, 1105.5, 1047.4, 898.7, 739.1, 704.7 cm^-1

MS (EI, m/z)  [M]⁺ calculated for C₁₅H₁₇N₁O₃⁺ 259.1203, found 259.1202

Anal. Calcd for C₁₅H₁₇N₁O₃: C, 69.48; H, 6.61; N, 5.40. Found: C, 69.61; H, 6.68; N, 5.40