Incorporation of Axial Chirality into Phosphino-Imidazoline Ligands for Enantioselective Catalysis

A complementary
strategy for ligand tuning that enables controlling
ligand conformation is described here. The concept is demonstrated
with new ligands that are employed in the catalytic enantioselective
preparation of the highly important C2-aminoalkyl five-membered heterocycle
motif. The alkynylation/cyclization sequence developed here is convergent,
highly modular, and allows for a complementary scope to the heteroarylation
of imines. This new ligand platform should offer new possibilities
for expanding the use of PHIM-type ligands in a large variety of new
transformations.