Asymmetric addition of diethylzinc to benzaldehyde catalyzed by silica-immobilized titanium(IV) complexes of N-sulfonylated amino alcohols

A chiral (1R,2S)-2-(p-toluenesulfonylamino)-1,3-diphenyl-1-propanol derived catalyst was synthesized and successfully grafted onto amorphous silica gel and mesoporous silica (MCM-41) by a facile approach. This is the first use of silica-immobilized titanium(IV) complexes of N-sulfonylated amino alcohols for the asymmetric addition of diethylzinc to benzaldehyde with good enantioselectivity (80% e.e.). Particularly, after readily recoverble procedure, the catalyst was able to be reused in multiple catalytic runs (up to 10 times) without loss of enantioselectivity.

Graphical abstractSilica-immobilized titanium(IV) complexes of sulfonylated amino alcohols were used for the asymmetric addition of diethylzinc to benzaldehyde with good enantioselectivity (80% e.e.). The catalyst was able to be recovered and reused in multiple catalytic runs (up to 10 times) without loss of enantioselectivity. Figure optionsDownload full-size imageDownload as PowerPoint slide