The synthesis of silica-supported chiral BINOL: Application in Ti-catalyzed asymmetric addition of diethylzinc to aldehydes

Chiral BINOL was covalently anchored on two different pore sized mesoporous silica (SBA-15 (7.5 nm) and MCF (14 nm)). These heterogenized ligands were used in Ti-catalyzed asymmetric addition of diethylzinc to aldehydes. High catalytic activity with excellent enantioselectivity (up to 94% ee) for secondary alcohols was achieved using MCF supported chiral BINOL under heterogeneous reaction conditions. Good to excellent enantioselectivity (ee, 68–91%) was also achieved with various small to bulkier aldehydes. The MCF supported catalyst was reused in multiple catalytic runs without loss of enantioselectivity.

Graphical abstractSilica-supported chiral BINOL was synthesized on two different pore sized mesoporous silica (SBA-15 (7.5 nm) and MCF (14 nm)), and shown to be highly active with an excellent enantioselectivity (up to 94% ee) in Ti-catalyzed asymmetric addition of diethylzinc to aldehydes. The MCF supported catalyst was reused in multiple catalytic runs without loss of enantioselectivity.Figure optionsDownload full-size imageDownload as PowerPoint slide