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

• Published in: Journal of molecular catalysis. A, Chemical Chemical, 2008-02, Vol.280 (1), p.106-114
• Main Authors: Pathak, Kavita, Ahmad, Irshad, Abdi, Sayed H.R., Kureshy, Rukhsana I., Khan, Noor-ul H., Jasra, Raksh V.
• Format: Article
• Language: English
• Subjects: Aldehydes; Asymmetric addition; Catalysis; Chemistry; Colloidal state and disperse state; Diethylzinc; Exact sciences and technology; General and physical chemistry; Mesoporous silica; Porous materials; Silica supported BINOL; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/j.molcata.2007.10.034

Silica-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. ▪ 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.