Design of a well-defined, silica-supported chiral Zn scaffold for enantioselective catalysis.

New compound Zn[(S,S)-iPr-pybox](Et)(2) (1) was fully characterized, including by X-ray diffraction structural studies. Its grafting onto partially dehydroxylated silica affords material 2, which bears well-defined chiral ([triple bond]SiO)Zn[(S,S)-iPr-pybox](Et) sites. Hybrid material 2 displays significantly better catalytic performances than 1 in enantioselective silylcyanation, thus demonstrating a beneficial grafting effect.