New alternative route strategy to obtain artificial imine reductases based on Vancomycin as source of chirality

Vancomycin (Van) is a glycopeptide antibiotic active against Gram positive infections. Its activity is due to a selective binding to D-Ala-D-Ala terminus of peptidoglycan precursor hampering the formation of the bacterial cell wall. Recently, it was found that several biological effects of Van are also related to its ability to bind both Cu(II) and Zn(II) metal ions under physiological/neutral conditions. Starting from these two different interaction modes of Van, we focused our attention on the possibility to obtain two different artificial imine reductases able to be used in ATH of cyclic imines. By the direct interaction between Van and [IrCp*Cl2]2 the first catalyst obtained was able to reduce quinaldine with a 61% e.e. while by “trojan-horse” strategy anchoring to the ligand based on opportunely modified ethylenediamine belonging a D-ala-D-ala moiety, the enantioselectivity in the reduction of quinaldine raised to 70%.