To a flame-dried 100-mL round-bottomed flask equipped with a magnetic stir bar was added crude alcohol 4-8 (4.2 g, 12.1 mmol, 1.0 equiv) and CH2Cl2 (21 mL, 0.5 M). The reaction vessel was then placed in a 0 °C ice-water bath. To the stirred reaction mixture was added acetic anhydride (3.9 mL, 42 mmol, 3.5 equiv) dropwise over 5 minutes. Following this, 4-(dimethylamino)pyridine (260 mg, 2.4 mmol, 0.2 equiv) was added in one portion. After stirring for 5 minutes at 0 °C, pyridine (5.1 mL, 63.0 mmol, 5.0 equiv) was added dropwise over 5 minutes and then the reaction flask was transferred to an ambient temperature water bath.