Potassium Carbonate → 2-((R)-1-tert-butoxycarbonylamino-ethyl)-4,5-dihydrooxazole-4-carboxylic acid methyl ester

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Reaction Conditions

Reaction Steps

In a round-bottomed flask, 2-((R)-2-tert-butoxycarbonylamino-propionylamino)-3-hydroxy-propionic acid methyl ester (419 mg, 1.3 mmol) was dissolved in dichloromethane (11 ml). The solution was cooled to −76° C. and DAST (0.20 ml, 1.51 mmol) was added dropwise. The light yellow solution was stirred at −76° C. for 2 h then anhydrous potassium carbonate (269 mg, 1.95 mmol) was added in one portion. The reaction mixture was allowed to warm to room temperature, quenched with 10 ml of saturated aqueous NaHCO3 and extracted with dichloromethane (3×). The organic layers were combined, dried over sodium sulfate, filtered and concentrated to afford 339 mg (91%) of 2-((R)-1-tert-butoxycarbonylamino-ethyl)-4,5-dihydro-oxazole-4-carboxylic acid methyl ester as a brown oil.

Provenance & Evidence