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

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.

Graphical abstractA new class of chiral ligands, based on the benzoxazin nucleus, has been designed and synthesized. Application of the chiral ligand in the palladium catalyzed-allylic substitution of 1,3-diphenyl-2-propenylacetate with dimethyl malonate gave enantioselectivities of up to 62%ee.Figure optionsDownload full-size imageDownload as PowerPoint slide