Multifunctional Chiral Silanol Ligands for Enantioselective Catalysis

We report transition metal catalysis using novel chiral metal-chelating ligands featuring a silanol coordinating group and peptide-like aminoamide scaffold. The catalytic properties of the silanol ligands are demonstrated through an enantioselective Cu-catalyzed N−H insertion affording unnatural amino acid derivatives in high selectivity. Our investigations into the silanol coordination mode include DFT calculations, ligand analogs, NMR and X-ray structure analyses, which support the formation of an H-bond stabilized silanol-chelating copper carbenoid complex. A π-π stacking interaction revealed by DFT calculations is proposed to enable selectivity for aryl diazoacetate substrates, overcoming the traditional limitations of using these substrates.