A new class of nitrogen based chiral ligands: 2 H-1,3-benzoxazines. Ligand synthesis, X-ray structural studies and asymmetric catalysis

Abstract

A new class of chiral ligands, e.g., (−)- 9, based on the benzoxazine nucleus, has been designed and synthesized in three steps from the commercially available starting materials salicylamide and (−)-menthone. Application of (−)- 9 in the palladium catalyzed-allylic substitution of 1,3-diphenyl-2-propenylacetate with dimethyl malonate gave enantioselectivities of up to 62%ee. Ees of 42% and 20% in asymmetric hydrosilylations and diethylzinc additions, respectively, were also obtained.