Chiral 3d-transition metal catalysts on the basis of novel tetradentate bis(iminoalkoxid) ligands and their investigation in the asymmetric catalysis of multiple bond transformations (epoxidation, alkynylation of ketones)

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For the pharmaceutical industry, it is of great interest to obtain enantiomerically pure products, since normally only one enantiomer shows the corresponding pharmacological effect. Accordingly, the enantioselective synthesis of chiral molecules is subject of intense research. One way to accomplish this is through the use of chiral catalysts. With them it is possible to perform atom efficient synthesis and thus avoid waste. This is both economically and ecologically wise.Therefore, asymmetric catalysts with novel chiral, tetradentate bis(iminoalcohol) ligands should be developed in this research project. Initially, different complexes with 3d transition metals (titanium, chromium, manganese, iron, copper, zinc) should be synthesized. In addition the synthesis of bimetallic complexes should be tried, since these could have better catalytic properties due to cooperative effects. The properties of the complexes should be tested in the asymmetric catalysis of multiple bond transformations (epoxidation, alkynylation of ketones). By varying the substituents of the ligand, the catalysts should get optimized to achieve high enantiomeric excesses. Overall, an inexpensive and highly variable, chiral ligand system should be developed that is easy to synthesize and its complexes are able to compete in catalysis with the established salen complexes.