intramolecular opening of the 1-Boc-β-lactam, initiated by 7-exotrig ring closure from the NH2 of the Orn side chain. The synthetic route is applied to the stereoselective preparation of enantiomerically pure 4-amino-3-methyl-2-oxoazepane-4-carboxylate derivatives, for which the structure and configuration is confirmed by X-ray diffraction. Molecular modeling and NMR experiments indicate that these quaternary
Experimental and Theoretical Studies on the Rearrangement of 2-Oxoazepane α,α-Amino Acids into 2′-Oxopiperidine β<sup>2,3,3</sup>-Amino Acids: An Example of Intramolecular Catalysis
Enantiopure β‐amino acids represent interesting scaffolds for peptidomimetics, foldamers and bioactive compounds. However, the synthesis of highlysubstituted analogues is still a major challenge. Herein, we describe the spontaneous rearrangement of 4‐carboxy‐2‐oxoazepane α,α‐amino acids to lead to 2′‐oxopiperidine‐containing β2,3,3‐amino acids, upon basic or acid hydrolysis of the 2‐oxoazepane α,α‐amino