Potassium Carbonate → di-tert-butyl (2S)-2-[(tert-butoxycarbonyl)amino]-5-(4-{[(4S,5S)-2,2-dimethyl-5-({[(4-methylphenyl)sulfonyl]oxy}methyl)-1,3-dioxolan-4-yl]methoxy}benzyl)hexanedioate

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Reaction Steps

500 mg (1.04 mmol) (2S)-2-tert.-Butoxycarbonylamino-5-(4-hydroxy-benzyl)-hexanedioic acid di-tert.-butyl ester, 144 mg (1.04 mmol) potassium carbonate and 491 mg (1.04 mmol) [(4S,5S)-2,2-dimethyl-1,3-dioxolane-4,5-diyl]bis(methylene) bis(4-methylbenzenesulfonate) in 12 mL DMF were heated in a microwave at 100° C. for 2 h. Brine (300 mL) was added and the mixture was extracted with dichloromethane (3×100 mL). The combined organic fractions were dried over sodium sulfate and concentracted. The crude product was purified by Flash chromatography (Silica, 2-40% ethyl acetate in hexane) to afford 430 mg (52%) di-tert-butyl (2S)-2-[(tert-butoxycarbonyl)amino]-5-(4-{[(4S,5S)-2,2-dimethyl-5-({[(4-methylphenyl)sulfonyl]oxy}methyl)-1,3-dioxolan-4-yl]methoxy}benzyl)hexanedioate.

Provenance & Evidence