Synthesis of chiral titanium-containing phosphinoamide ligands for enantioselective heterobimetallic catalysis

The synthesis of six chiral titanium-containing phosphinoamide ligands is discussed. These ligands assemble chiral heterobimetallic Pd-Ti complexes, enable enantioselective intramolecular allylic aminations with hindered amine nucleophiles and achieve selectivity up to 53% ee. Mechanistic studies demonstrate the reversibility of the enantio-determining C-N bond forming step, which leads to a gradual increase in the % ee of the reaction over time. These results represent a rare example of enan-tioselective heterobimetallic catalysis and suggest that these new ligands could find broad application in enantioselective transition metal catalysis. (C) 2019 Elsevier Ltd. All rights reserved.