Ethyl Acetate → Methyl 2-[(tert-butoxycarbonyl)amino]-4-(4-chlorophenyl)-5-oxohexanoate

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Reaction Steps

To a solution of methyl N-(tert-butoxycarbonyl)-3-iodo-L-alaninate (215 g, 652 mmol) and 4-chlorophenylacetone (100 g, 593 mmol) in N,N-dimethylformamide (1.5 L) was added cesium carbonate (483 g, 1.48 mol) at room temperature. After 4 h, the mixture was then added to a stirring solution of pH 7 buffer and EtOAc. The aqueous layer was extracted with EtOAc and the combined organics were washed with pH 7 buffer, dried over sodium sulfate, filtered and concentrated. The crude product was purified by silica gel chromatography (10% ethyl acetate/heptane→30% ethyl acetate/heptane) to provide the title compound as a mixture of diastereomers. MS: m/z=392.1 (M+Na).

Provenance & Evidence