Synthesis and application of new iminopyridine ligands in the enantioselective palladium-catalyzed allylic alkylation

• New chiral iminopyridines were obtained from pyridyl and quinolinyl aldehydes.
• New chiral iminopyridines were obtained from a variety of chiral or achiral amines.
• New ligands were assessed in the enantioselective Pd-catalyzed allylic substitution.
• 1,3-Diphenylprop-2-enylmalonate was obtained with enantioselectivities up to 62% ee.

A variety of iminopyridines were obtained by condensation of chiral amines with pyridine-2-carboxaldehyde and quinoline-8-carbaldehyde, or of aminoalkylpyridine derivatives with chiral ketones. These ligands were assessed in the enantioselective palladium catalyzed allylic substitution of 1,3-diphenylprop-2-enyl acetate with dimethyl malonate affording the product dimethyl 1,3-diphenylprop-2-enylmalonate in good yields and moderate enantioselectivities (up to 62% ee). Catalytic activity and enantioselectivity were found to be highly dependent upon the steric properties of the ligands. The best enantioselectivity (62% ee) was obtained by an iminopyridine based on a camphane skeleton.

Figure optionsDownload high-quality image (99 K)Download as PowerPoint slide