Asymmetric Access to Peptidyl β3‐Aldehydes by Coupling of N‐Phthalyl α‐Amino Acids with a Synthetic Heterocyclic β‐Amino Aldehyde Precursor

Asymmetric access to novel N‐protected (di)peptidyl β3‐aldehydes (“β3‐PAs”) has been achieved through direct coupling of a chiral non‐racemic 6‐alkoxytetrahydrooxazinone with N‐phthalyl L‐α‐amino acids. Kinetic resolution allows for the fruitful use of racemic amino acids in this process. Acidic hydrolysis of the diastereomerically pure, coupling products leads to the title N‐phthalyl‐β3‐PAs in high yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)