An Efficient Synthesis of Achiral and Chiral Cyclic Dehydro-α-Amino Acid Derivatives Through Nucleophilic Addition of Amines to β,γ-Unsaturatedα-Keto Esters

A very simple and efficient synthesis of 3‐amino‐1,5‐dihydro‐2H‐pyrrol‐2‐ones is reported. These cyclic dehydro‐amino acid derivatives with a stereogenic center at the 5‐position were obtained by the addition of two equivalents of amine to β,γ‐unsaturated keto esters. These cyclic enamines can also be obtained by the three‐component reaction of ethyl pyruvate, amines and aldehydes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)