Chiral Metallacyclophanes: Self-Assembly, Characterization, and Application in Asymmetric Catalysis

A family of chiral metallacyclophanes has been readily assembled based on robust Pt-acetylide linkage and characterized by a variety of
spectroscopic techniques and X-ray crystallography. The steric congestion around the chiral dihydroxy groups in rigid metallacyclophane 4
prevents their reactions with Ti(OiPr)4 to form active catalysts for enantioselective diethylzinc additions to aromatic aldehydes. In contrast,
chiral dihydroxy groups in more flexible unclosed metallacyclophane 5 are effective ligands for enantioselective catalytic diethylzinc additions
to aromatic aldehydes.