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Structural Characterization of an Enantiomerically Pure Amino Acid Imidazolide and Direct Formation of the β-Lactam Nucleus from an α-Amino Acid

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posted on 07.02.2008, 00:00 by Brian S. Gerstenberger, Jinzhen Lin, Yvette S. Mimieux, Lauren E. Brown, Allen G. Oliver, Joseph P. Konopelski
Decomposition of a diazo β-ketoamide derived from N-trityl serine imidazolide and N-protected acetanilides provides, instead of the expected 3-acyloxindole product, an enantiomerically pure (EP) β-lactam. The amino acid stereocenter is incorporated, the second chiral center is induced, and trityl protection of the β-lactam ring is realized for the first time. The desired 3-acyloxindole is obtained from oxindole and Tr-Ser(OBn)-imidazole, the X-ray of which provides the first structural determination of an EP amino acid imidazolide.