Drawing inspiration from nature in catalyst development Terpenes are the largest class of chemicals produced in nature, however chemists across the globe have not yet been able to mimic the efficient cyclization processes found in nature with man-made catalysts. We spoke to Professor Konrad Tiefenbacher about the Terpenecat project’s work in developing selective catalysts for terpene cyclizations The largest class of chemical compounds produced in nature, terpenes are commonly used in medicine, including in anti-cancer and anti-malarial drugs. While nature is able to produce these compounds efficiently, organic chemists have not yet been able to develop a similarly effective method, an issue that lies at the core of the Terpenecat project’s research. “The aim of the project is to develop selective catalysts for terpene cyclizations,” says Professor Konrad Tiefenbacher, the project’s Principal Investigator. Terpene cyclizations are among the most complex reactions performed in nature, now researchers aim to develop selective catalysts for this purpose, which could open up the possibility of producing an almost limitless number of cyclized structures. Bridging the gap between supramolecular chemistry and current synthetic challenges: Developing artificial catalysts for the tailto-head terpene cyclization. TERPENECAT Project ID: 714620 Funded under: H2020-EU.1.1. - EXCELLENT SCIENCE - European Research Council (ERC) ERC-2016-STG - ERC Starting Grant funded EU contribution: EUR 1 500 000 Professor Konrad Tiefenbacher University of Basel St. Johanns-Ring 19, CH-4056 Basel Switzerland T: 0041 612 075 609 E: konrad.tiefenbacher@unibas.ch W: https://nanocat.chemie. unibas.ch/en/research/ W: http://cordis.europa.eu/ project/rcn/206316_en.html Konrad received his chemical basic education at the Technical University of Vienna and the University of Texas in Austin. After finishing his diploma thesis in the lab of Prof. Fröhlich, he pursued his interest in total synthesis of biologically active natural products during a Ph.D. in the lab of Prof. Mulzer at the University of Vienna. He then moved to Prof. Rebek’s lab at The Scripps Research Institute in La Jolla to learn about molecular recognition and self-assembly. In December 2011 he started his independent career as a Juniorprofessor (W1-position) at the Technical University Munich. In June 2016 he was appointed to a dual tenure track assistant professorship at the University of Basel and the ETH Zürich.
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“If you imagine folding a cable, you could also fold these linear terpenes in nearly limitless different kinds of ways,” explains Professor Tiefenbacher. “So we could directly produce hundreds – maybe thousands – of different cyclized structures from essentially one simple starting material.”
Supramolecular catalyst utilized by the Terepenecat project.
and artemisinin, which are used as anti-cancer and anti-malarial drugs, respectively. “One of the goals in the project is to make new derivatives of artemisinin. We aim to take this antimalaria agent, and to modify specific parts of it,” continues Professor Tiefenbacher. “That means we would start with a slightly modified starting material, and try to cyclize it to the artemisinin framework. So, after folding the cable in the right conformation and gluing it together, we would have a new artemisinin derivative.” This work could open up new avenues of research in terpene chemistry. Controlling terpene cyclization with man-made catalysts could eventually lead to simplified terpene production, yet the project is still in its early stages, so Professor Tiefenbacher is continuing to develop new catalysts. “So far we have found one catalyst which is able to perform this cyclization, but it’s not really selective. We are trying to understand the
One of the goals in the project is to make new derivatives of artemisinin. We aim to take this anti-malaria agent, and to modify specific parts of it. That means we would start with a slightly modified starting material, and try to cyclize it to the artemisinin framework Substrate conformation A major focus now is learning how these hundreds or thousands of different products can be selectively produced. A key step in this is controlling the conformation of the substrate; Professor Tiefenbacher again draws on the example of folding a cable. “Conformation would just be to put the cable into the right shape. With terpenes, first we fold the starting material, and then during the cyclization process it’s glued together,” he explains. From here, researchers can then look to learn how to construct terpene structures like taxol
principles which enable this catalyst to perform this cyclization,” he says. A lot has been achieved already in terms of understanding why this catalyst is catalytically active, now researchers are looking further ahead. “Over the next few years we plan to modify the selectivity of this catalyst and investigate what other kinds of products could be formed in this way,” outlines Professor Tiefenbacher. “Eventually, we want to be able to design and construct catalysts which are able to selectively cyclize a terpene in a desired manner.”
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