The synthesis of phosphine oxide-linked bis(oxazoline) ligands and their application in asymmetric allylic alkylation
作者:Yu Jin、Da-Ming Du
DOI:10.1016/j.tet.2012.02.078
日期:2012.5
The phosphine oxide-linked bis(oxazoline) ligands were designed and synthesized in two ways. One is the coupling of Grignard reagent derived from 2-(2-bromophenyl)oxazoline with phenylphosphonic dichloride, another route is the condensation of bis(2-formylphenyl)(phenyl)phosphine oxide with chiral amino alcohols followed by NBS oxidation. These new bis(oxazoline) ligands were applied in Pd-catalyzed
New Schiff bases derived from chiral d‐camphor were determined to be effective phosphine ligands for the asymmetric palladium‐catalyzed allylic alkylation of activated methylene compounds, the allylic etherification of alcohols, and the allylic amination of primary amines or secondary amines, in which the corresponding products with various functional groups were achieved in good yields with excellent
Novel Chiral Diamino-Oligothiophenes as Valuable Ligands in Pd-Catalyzed Allylic Alkylations. On the “Primary” Role of “Secondary” Interactions in Asymmetric Catalysis
A new class of chiral C2-symmetrical diamino-oligothiophenes is described to be effective in catalyzing Pd-mediated asymmetricallylicalkylations in a highly enantioselective manner. The combination of experimental as well as crystallographic evidence revealed the key role played by sulfur-based heteroaromatic rings in the stereodiscriminating step of the procedure. In particular, unprecedented non-covalent
A new type of chiral sulfoxide-phosphine ligands have been developed by a rational combination of two privileged scaffolds for Pd-catalyzed asymmetric allylicalkylation reactions. Under optimized conditions, generally high yields (up to 97%) and excellent enantioselectivities (up to >99% ee) were obtained.