In a 100 mL Schlenk flask, 19 (0.19 g, 0.49 mmol) was dissolved in dry EtOH (12 mL) and allowed to stir on ice. In a 50 mL Schlenk flask, NaBH4 (0.17 g, 4.45 mmol) was dissolved in dry EtOH (6 mL) and allowed to stir on ice. The solution containing NaBH4 was cannula transferred into the flask containing 19. The mixture was allowed to react at 0 °C for 1 h, after which the reaction was quenched with degassed water. The product was extracted with hexane, which was then