A new approach to the asymmetric Mannich reaction catalyzed by chiral N, N-dioxide-metal complexes

A highly efficient asymmetric Mannich-type reaction between alpha-tetralone-derived beta-keto esters/amides and 1,3,5-triaryl-1,3,5-triazinanes was realized in the presence of chiral N,N'-dioxide-Ni(II) or Mg(II) complex. A variety of optically active beta-amino compounds with all-carbon quaternary stereocenters were obtained in good yields with excellent enantioselectivities. A possible transition state was proposed based on these experiments and previous reports.