To this flask was added THF (28 mL, 0.5 M) via cannula, and this mixture was allowed to stir at room temperature for 10 minutes to allow for complete dissolution of KHMDS solid. The reaction vessel was transferred to a -78 °C saturated dry-ice acetone bath and stirred for 10 minutes before a solution of ketone 11-5 (2.5 g, 12.7 mmol, 1.0 equiv) in THF (13.0 mL, 1.0 M) was added over 5 minutes. After stirring at this temperature for 30 minutes, methyl trifluoromethanesulfonate (1.5 mL, 14.0 mmol, 1.1 equiv) was added dropwise over two minutes. The reaction mixture was allowed to stir at this temperature for 15 minutes before the reaction vessel was removed from dry-ice acetone bath, and the reaction mixture was allowed to slowly warm up to room temperature over 1.5 hours.