Catalyst- and Additive-free Synthesis of -Pyrrolyl Amides upon Treatment of -Keto Amides with 4-Hydroxy-L-proline

A catalyst- and additive-free synthesis of alpha-pyrrolyl amides was easily achieved upon treatment of 4-hydroxy-L-proline with alpha-keto amides. Broad substrate scope, good functional group tolerance, and operational simplicity are the notable advantages of this protocol. Furthermore, gram-scale synthesis and further transformation of the resultant products into newly functionalized compounds definitely demonstrated the synthetic utility of this method.