Catalytic Asymmetric Conjugate Addition of α-Cyanoketones for the Construction of a Quaternary Stereogenic Center

The catalytic asymmetric conjugate addition of α-cyanoketone pronucleophiles to vinyl ketones promoted by a Y/1 catalyst is described. High enantioselectivity was observed for a range of aromatic vinyl ketones, providing 1,5-dicarbonyl compounds bearing an all-carbon quaternary stereogenic center. The product was successfully converted to a spiro-piperidine entity and a bicyclo[3.3.0]octane framework through either the reduction of nitrile or intramolecular pinacol coupling.