Application of a Heterogeneous Chiral Titanium Catalyst Derived from Silica-Supported 3‑Aryl H₈‑BINOL to Enantioselective Alkylation and Arylation of Aldehydes

A 3-aryl H₈-BINOL was grafted on the surface of silica gel using a hydrosilane derivative as a precursor, and the resulting silica-supported ligand (6 mol %) was employed in the enantioselective alkylation and arylation of aldehydes in the presence of Ti­(OⁱPr)₄. The reactions using Et₂Zn, Et₃B, and aryl Grignard reagents all afforded the corresponding adducts in high enantioselectivities and yields. The silica-immobilized titanium catalyst could be reused up to 14 times without appreciable deterioration of the activity.