To a flame-dried 100-mL round-bottomed flask equipped with a magnetic stir bar was added crude intermediate alcohol and CH2Cl2 (15 mL, 0.3 M). The reaction vessel was transferred to an ice-water bath cooled to 0 °C, and pyridine (0.97 mL, 12.0 mmol, 3.0 equiv) was added dropwise over one minute. Following this, thionyl chloride (0.58 mL, 8.0 mmol, 2.0 equiv) was added dropwise over five minutes. After the addition was complete, the reaction vessel was removed from the ice-water bath and allowed to warm to room temperature.