4-(Tert-butoxy)-4-oxobutanoic acid → (R)-tert-butyl 4-(1-(4-bromophenyl)-4-ethoxy-4-oxobutan-2-ylamino)-4-oxobutanoate

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Reaction Steps

To a solution of 4-tert-butoxy-4-oxobutanoic acid (2.38 g, 13.64 mmol) in DMF (30 mL) and DCM (30 mL) is added (R)-ethyl 3-amino-4-(4-bromophenyl)butanoate hydrochloride (4 g, 12.4 mmol), HATU (5.19 g, 13.64 mmol), and TEA (6.91 mL, 49.6 mmol). After stirring at room temperature for 2 hours, the reaction is quenched with H2O, and the crude is diluted with EtOAc, the organic layer is washed with brine, dried over Na2SO4, filtered, and concentrated under reduced pressure to give (R)-tert-butyl 4-(1-(4-bromophenyl)-4-ethoxy-4-oxobutan-2-ylamino)-4-oxobutanoate (4.0 g). HPLC retention time=1.70 minutes (condition A); MS (m+1)=444.1.

Provenance & Evidence