Hydrochloric Acid → Ethyl 4-((tert-butoxycarbonyl)amino)-2-cyano-2-cyclopropylbutanoate

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Reaction Steps

To a solution of ethyl cyano(cyclopropyl)acetate (27 g) obtained in Step A of Example 103 in toluene (400 mL) were added cesium carbonate (88 g), tetrabutylammonium bromide (5.8 g) and tert-butyl 1,2,3-oxathiazolidine-3-carboxylate 2,2-dioxide (40 g), and the mixture was stirred overnight at room temperature. The reaction mixture was neutralized with 0.5 M hydrochloric acid (400 mL), and extracted with ethyl acetate. The obtained organic layer was washed successively with water and saturated brine, and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate) to give the title compound (45 g).

Provenance & Evidence