A new approach to the asymmetric Mannich reaction catalyzed by chiral N,N′-dioxide–metal complexes†
Abstract
A highly efficient asymmetric Mannich-type reaction between α-tetralone-derived β-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 β-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.