102229-10-7

102191-92-4

Oxalyl chloride (13.7 mL, 162.2 mmol) was dissolved in anhydrous dichloromethane (400 mL) under nitrogen protection and cooled to -78°C. Dimethyl sulfoxide (25.1 mL, 353.9 mmol) was added slowly and stirred for 30 minutes. Subsequently, a solution of 2-((tert-butyldimethylsilyl)oxy)ethanol (26.0 g, 147.5 mmol) in anhydrous dichloromethane (100 mL) was added dropwise. After maintaining -78 °C and continuing to stir for 30 min, triethylamine (102.74 mL, 737.0 mmol) was added slowly and dropwise. The reaction mixture was stirred at -78 °C for another 30 min, then gradually warmed up to room temperature and continued stirring for 1 h. The reaction mixture was then stirred at -78 °C for 1 h. The reaction mixture was then gradually warmed up to room temperature. The pH of the reaction mixture was adjusted to 4 with aqueous 2N hydrochloric acid and then extracted with dichloromethane (3 x 400 mL). The organic layers were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give 2-((tert-butyldimethylsilyl)oxy)acetaldehyde (34.0 g, 100%) as a colorless oil. The product can be used directly in the subsequent reaction without further purification.