4-(tert-ButyldiMethylsilyloxy)butanal

Synthesis

To a solution of oxalyl chloride (2.1 mL, 24 mmol, 1.2 equivalents) in CH2Cl2 (30 mL) cooled at −78 °C was added dropwise a solution of dimethylsulfoxide (DMSO 3.3 mL, 21 mmol, 1.1 equivalents) in CH2Cl2 (32 mL). After 5 min, a solution of 4-(tert-butyldimethylsilanyloxy)butan-1-ol (4.0 g, 20 mmol, 1.0 equivalents) in CH2Cl2 (26 mL) was added. The reaction mixture was then stirred for 15 min at  −78 °C and triethylamine (14.0 mL, 100 mmol, 5.00 equivalents) was added in  1 portion. After 10 min at −78 °C, the mixture was allowed to warm to room temperature and diluted with CH2Cl2 (140 mL). The organic layer was successively washed with a saturated aqueous solution of NH4Cl (30 mL) and brine (2 × 30 mL). The combined organic extracts were dried over MgSO4, fifiltered, and concentrated under reduced pressure. Purifification by flflash chromatography on silica gel (petroleum ether/EtOAc: 90/10) afforded 3.88 g (96% yield) of the aldehyde as a colorless oil.

Reference: Taillier, C.; Gille, B.; Bellosta, V.; Cossy, J. J. Org. Chem. 2005, 70, 2097−2108.