Comparative Study of 1,5‐Dinitrogen Schiff Bases as Potential Ligands in Palladium‐Catalyzed Allylic Alkylation.

Abstract

1-(2'-Pyrido and 2'-quinolino)-(1R)-arylethylamino)-ethylidenes (7-12) were prepared as potential ligands in Pd II catalytic complexes for enantioselective allylic alkylation of 1,3-diphenyl-1-acetoxy-propene-2 (15). Alkylation with palladium complexes of 7-12 yielded 1,3-diphenyl-1-dimethylmalonyl-propene-2 (14) with enantioselectivity up to 55 % e.e. Enantioselectivity is discussed in view of the results recently reported for structurally related 1,5-bidentate dinitrogen ligands of C 1 symmetry. Reversal of enantioselectivity observed for the ligands 10 and 11 is attributed to the inversion of steric requirements in the second coordination sphere of their catalytic complexes.