Synthesis of α-Quaternary Formimides and Aldehydes through Umpolung Asymmetric Copper Catalysis with Isocyanides

A highly regio- and enantioselective copper catalyzed three-component coupling of isocyanides, hydrosilanes, and gamma,gamma-disubstituted allylic phosphates/chlorides to afford chiral alpha-quaternary formimides was enabled by the combined use of our original chiral naphthol-carbene ligand as a functional Cu-supporting ligand and LiOtBu as a stoichiometric Lewis base for Si. The formimides were readily converted to alpha-quaternary aldehydes.