Book of Abstracts - Ruhr-Universität Bochum

OP-24
ISBOMC `10 5.7 – 9.7. 2010 Ruhr-Universität Bochum
DNA-Organometallic Hybrid Catalysts
Andres Jäschke, * Pierre Fournier, a Michaela Caprioara, a and Matthias Höhne a
a Heidelberg University, Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld
364, 69120 Heidelberg, Germany. E-mail: jaeschke@uni-hd.de
Hybrid catalysis combines homogeneous chemical catalysts with biopolymers to develop selective
catalysts for organic reactions. While proteins have been used as hosts for various transition metal
complexes, 1 only few published examples are based on nucleic acids. 2 In these reports high
stereoselectivities were obtained in Diels-Alder reactions, Michael additions and fluorinations, with
DNA as sole source of chirality, but all these systems relied on Lewis acid catalysis by Cu II ions. Our
goal is the application of DNA-conjugated transition metal complexes in organometallic catalysis, as
this kind of catalysis is widespread among synthetically useful reactions.
We recently presented DNA-based systems that use Ir I -diene chemistry to catalyze an allylic
substitution in aqueous medium. 3 Towards this end, we covalently attach transition metal ligands, like
phosphinoxazoline and diene ligands, to specific positions of oligonucleotides. 4
Our approach is based on a modular design where a 19mer oligodeoxynucleotide carrying a transition
metal ligand is combined with different DNA or RNA counterstrands, thereby forming perfect and
imperfect duplexes that provide subtle changes in the environment of the metal center. The covalent
attachment of the ligand guarantees its specific, reproducible positioning on nucleic acid structures.
We demonstrate that catalysis occurs in the presence of DNA and its numerous functional groups, and
that the structure of the DNA modulates the stereochemical outcome of the reaction. 3
Recent work will be presented on the extension of our approach to other reactions, metals, and ligands,
and about rational and combinatorial strategies for improvement of performance and stereoselectivity.
References
Iridium(I)-catalyzed allylic amination using DNA-based ligands
1. (a) J. Steinreiber, T. R. Ward, Coord. Chem. Rev. 2008, 252, 751. (b) M. E. Wilson, G. M.
Whitesides, J. Am. Chem. Soc. 1978, 100, 306. (c) M. T. Reetz, M. Rentzsch, A. Pletsch, M. Maywald,
P. Maiwald, J. J. P. Peyralans, A. Maichele, Y. Fu, N. Jiao, F. Hollmann, R. Mondiere, A. Taglieber,
Tetrahedron 2007, 63, 6404. (d) A. Pordea, M. Creus, J. Panek, C. Duboc, D. Mathis, M. Novic, T. R.
Ward, J. Am. Chem. Soc. 2008, 130, 8085.
2. (a) G. Roelfes, B. L. Feringa, Angew. Chem. Int. Ed. 2005, 44, 3230. (b) N. S. Oltra, G. Roelfes,
Chem. Comm. 2008, 6039. (c) D. Coquière, Ben L. Feringa, G. Roelfes, Angew. Chem. Int. Ed. 2007,
46, 9308. (d) N. Shibata, H. Yasui, S. Nakamura, T. Toru, Synlett 2007, 1153.
3. P. Fournier, R. Fiammengo, A. Jäschke, Angew. Chem. Int. Ed. 2009, 48, 4226.
4. M. Caprioara, R. Fiammengo, M. Engeser, A. Jäschke, Chem. Eur. J. 2007, 13, 2089.
40