FWF - Entw. von het. Übergangs - Development of innovative catalysts for pharmaceutical industry

Project: Research project

Description

In the proposed work we aim to develop next-generation heterogeneous catalysts,

which include rigid (tripodal) tethers in order to control the distance of the catalytic moiety from the surface as well as the distance between the grafted complexes

which can be immobilized onto surfaces under controlled and mild conditions (no surface contamination with chemicals, immobilization at room temperature, etc.)

which show no or negligible metal leaching

which are highly active and selective for applications in the pharmaceutical industry and

which can be used as bifunctional catalysts, i.e., catalysts that feature two or more types of catalytic sites and are thus able to catalyze multistep reactions in a one-pot synthesis.



The following five milestones are part of the proposed work:


1. The first milestone involves the preparation of heterogeneous metallocenes (titanocenes and zirconocenes). As a first step, we will synthesize tripodal tethers, i.e., tethers that bear three functionalities for the immobilization on the surface and a fourth functional group for further derivatization. Secondly, we will immobilize these tethers onto silica surfaces. The immobilization method is based on a UV-mediated hydrosilylation, which allows highly controlled grafting under mild conditions. Finally, the immobilized tethers will be coupled with ethylenebis(indenyl)-metallocenes, which include a terminal functional group at the indenyl backbone.


2. The second milestone is the preparation of heterogeneous palladium catalysts. For this purpose, different N-ligands will be immobilized on silica and will then be metalated with Pd-complexes.


3. Modern surface spectroscopic methods including single crystal studies as well as high-surface-area characterization methods will be used by us in order to investigate in detail the immobilization chemistry and the distribution and concentration of active sites on the surfaces.


4. The immobilized metallocenes will then be utilized for enantioselective reductions of imines, ketones and other prochiral unsaturated compounds using hydrosilylation and hydrogenation procedures. The heterogeneous palladium catalysts will be tested for Buchwald-Hartwig reactions to prepare arylpiperazines and other important pharmaceutical products. Kinetic and mechanistic investigations will help us to optimize the reaction parameters and to allow an easy reaction scale-up.


5. The ultimate goal of this project, however, is to combine the various methods to develop bi- and multifunctional catalysts with a spatial control of the catalytic sites, i.e., materials that feature two or more catalytic compounds. This technology may have significant impact on other fields, such as (micro-)reactor design, therapeutic devices and sensing applications.



In summary, we intend to develop new and efficient catalysts for the preparation of pharmaceutical intermediates. Given the fact that the market for chiral drugs and fine chemicals is becoming increasingly important, this project will have significant impact and may lead to significant improvements in the field of pharmaceutical engineering.
StatusFinished
Effective start/end date1/01/071/01/10