Dimethyl Sulfoxide → tert-butyl N-(2-methyl-4-oxobutan-2-yl)carbamate

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Reaction Conditions

Reaction Steps

At −78° C. DMSO (1.22 ml, 17.2 mmol) was added to a solution of oxalyl chloride (1.1 ml, 12.9 mmol) in dichloromethane (15 ml). The mixture was stirred for 15 min at −78° C. A solution of 3-hydroxy-1,1-dimethylpropylcarbamic acid tert-butyl ester (1.75 g, 8.6 mmol) in dichloromethane (10 ml) was added dropwise over a period of 15 min. The solution was stirred at −78° C. for another 15 min. Triethylamine (6.0 ml, 43 mmol) was added. The solution was stirred at −78° C. for 5 min and then warmed to room temp. The solution was diluted with dichloromethane (100 ml) and extracted with 1N hydrochloric acid (100 ml). The aqueous phase was extracted with dichloromethane (50 ml). The combined organic layers were washed with a saturated solution of sodium hydrogencarbonate (100 ml) and dried over magnesium sulfate. The solvent was removed in vacuo. The crude product was purified by column chromatography on silica (140 g) with ethyl acetate/heptane (1:3) to give 1.10 g of 3-(tert-butoxycarbonylamino)-3-methylbutanal.

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