General procedure for the synthesis of tert-butyl 5-(hydroxymethyl)-1H-indole-1-carboxylate from tert-butyl 5-formyl-1H-indole-1-carboxylate: firstly, tert-butyl 5-formyl-1H-indole-1-carboxylate (12.23 mmol) was dissolved in methanol (30 mL) to obtain a solution. To this solution, sodium tetrahydroborate (0.463 g, 12.23 mmol) was slowly added at 0 °C. The reaction mixture was stirred continuously at 0 °C for 3 h, followed by stirring at room temperature overnight. After completion of the reaction, the resulting solution was diluted with water (40 mL) and extracted with ethyl acetate (3 x 30 mL). The organic layers were combined, washed sequentially with aqueous sodium carbonate and brine, dried over anhydrous sodium sulfate, and concentrated in vacuum to afford tert-butyl 5-(hydroxymethyl)-1H-indole-1-carboxylate (2.5 g, 10.11 mmol, 83% yield) as a yellow oil.LCMS analysis showed m/z = 270.3 [M + Na]+.
