Hydrogen Peroxide → Di-tert-butyl (2S,4S)-2-(Boc-amino)-4-(3-hydroxypropyl)pentanedioate

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Reaction Steps

15.58 g (39 mmol) of di-tert-butyl (2S,4S)-4-allyl-2-tert-butoxycarbonylamino-pentanedioate 5a were dissolved in 200 mL of tetrahydrofuran (THF) and cooled in an ice-bath. Over a period of about 20 minutes, 54.6 mL (54.6 mmol) of 1 M diboran/tetrahydrofuran complex in tetrahydrofuran were added dropwise with ice-cooling and under nitrogen, and the mixture was stirred on ice for 2 h and at room temperature overnight. It was cooled again to 0° C. and 58.5 mL of 1 N aqueous sodium hydroxide solution and 58.5 mL of 30% aqueous hydrogen peroxide solution were then added dropwise. After 60 minutes, the mixture was diluted with water, the tetrahydrofuran was distilled off and the remaining aqueous solution was extracted with ethyl acetate. The organic phase was separated off, washed with water until neutral, dried over sodium sulphate and filtered, and the filtrate was concentrated. The crude product obtained in this manner was chromatographed on silica gel using a hexane/ethyl acetate gradient, and the appropriate fractions were combined and concentrated.

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