Step 2. To a solution of tert-butyl 3-formyl-1H-indole-1-carboxylate (44 g, 0.17 mol) in anhydrous ethanol (50 mL) was added sodium borohydride (16.6 g, 0.45 mol) in batches at 0 °C. The reaction mixture was stirred at room temperature for 3 hours. Upon completion of the reaction, the mixture was filtered to remove insoluble material. The filtrate was rotary evaporated to remove ethanol. The residue was dissolved in ethyl acetate (100 mL) and water (50 mL) for partitioning. The aqueous layer was further extracted with ethyl acetate (2 x 50 mL). The combined organic layers were washed with saturated saline (50 mL), dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give tert-butyl 3-(hydroxymethyl)-1H-indole-1-carboxylate (40 g, 95% yield). The product was characterized by 1H NMR (400 MHz, CDCl3): δ 1.59 (s, 9H), 4.77 (s, 2H), 7.19 (t, 1H), 7.25 (t, 1H), 7.51 (s, 1H), 7.57 (d, 1H), 8.06 (d, 1H).
