To a flame-dried 10-mL microwave vial equipped with a magnetic stir bar was added aldehyde 10-7 (84 mg, 0.32 mmol, 1.0 equiv). To the reaction vial was added a solution of enoxysilane 10-8 (100.0 mg, 0.32 mmol, 1.0 equiv) in CH2Cl2 (0.75 mL, 0.5 M). The reaction vial was then transferred to a saturated dry-ice acetone bath cooled to ⎯78 °C. After stirring at ⎯78 °C for 5 minutes, BF3•OEt2 (5.0 µL, 0.032 mmol, 0.1 equiv) was added, which resulted in an orange reaction mixture. Once the reaction mixture had stirred at ⎯78 °C for an additional 30 minutes, the dry-ice acetone bath was removed and the reaction mixture was allowed to gradually warm to room temperature.