Synthesis of Boron- and Silicon-Containing Amino Acids through Copper-Catalysed Conjugate Additions to Dehydroalanine Derivatives

A copper-based catalytic technique for the regioselective hydroboration and hydrosilylation of dehydroalanine derivatives has been developed. This method introduces synthetically versatile boron and silicon groups, while simultaneously performing a catalytic anti-Markovnikov hydrofunctionalization of dehydroalanines and dehydropeptides for the synthesis of amino acids and peptides bearing unnatural side-chains. The products obtained were expediently converted into valuable nonproteinogenic amino acid building blocks for polypeptide synthesis.