Ex Situ Synthesis of N-Capped Peptides in the Solution Phase via Palladium-Catalyzed Aminocarbonylation Utilizing Chloroform-COware.

We report the synthesis of N-capped peptides under mild conditions using the oxidative aminocarbonylation of aryl iodides and peptide esters as nucleophiles in the solution phase. Ex situ chloroform in chamber A generates CO, which diffuses to chamber B, which contains other reactants. This method offers N-capped peptides at 80 °C for 12 h. We synthesized 36 N-capped peptides using this method, including an anticancer drug bortezomib analogue, with an isolated yield ranging from 52 to 91%. The present method gives easy access to previously inaccessible N-capping groups, including heteroaromatic ring-capped groups, which enable robust analogue designs in peptide-based drug discovery.