Phosphate → (S)-benzyl 2-benzyl-2-(1-(benzyloxy)-3-(3-(benzyloxy)-4-hydroxyphenyl)-2-methyl-1-oxopropan-2-yl)hydrazinecarboxylate

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Reaction Steps

To a 500 mL round bottom flask were added (S)-2-(2-((benzyloxy)carbonyl)hydrazinyl)-3-(3,4-di hydroxyphenyl)-2-methylpropanoic acid compound with tetrahydrofuran (1:1), Compound 1, (10 g, 84 wt %, 19.42 mmol) and 100 mL DMF. Cesium carbonate (11.39 g, 35 mmol) was added, and the mixture was stirred at room temperature for 15 minutes. The mixture was cooled in an ice bath. Benzyl bromide (7.38 mL, 62.2 mmol) was added portionwise. The mixture was stirred in the ice bath overnight. The slurry was filtered, and the cake was washed with methyl t-butyl ether. The filtrate was mixed with water, and the layers were separated. The aqueous layer was extracted with methyl t-butyl ether. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, and concentrated. The crude was purified by flash chromatography using a 220 g silica column (0-30% ethyl acetate in heptanes) to afford Compound 2 as a colorless thick oil (1.20 g, 9.8%).

Provenance & Evidence