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25th Croatian meeting of chemists and chemical engineers, Poreč, 2017. Minimal Artificial Enzymes: Application of "backdoor induction" in asymmetric catalysis Minimalni umjetni enzimi: Primjena posredne indukcije u asimetričnoj katalizi Srećko I. Kirin Ruđer Bošković Institute, HR-10000 Zagreb, Croatia E-mail: [email protected] The development of new small-molecule transition metal catalysts for asymmetric reactions is often fuelled by imitating metalloenzyme active sites. Nevertheless, small-molecule transition metal catalysts are still easily outperformed by metalloenzymes in terms of both selectivity and reaction rates. It is obvious that mimicking the active site alone is not sufficient to replicate metalloenzyme activity. Therefore we design artificial metalloenzymes that contain not only an enzyme active site mimic but also a minimal functional outercoordination sphere. A major feature of these minimal artificial enzymes is "backdoor induction" of chirality via hydrogen bonding and other non-covalent interactions between distant chiral amide substituents, e. g. amino acids, diamines or dicarboxylic acids. Additional favorable properties are cheap synthesis by standard chemical methods as well as possible application to a broad range of substrates. In this presentation, several selected approaches for the development of new catalytic systems will be discussed [1]. Particular emphasis will be focused on supramolecular systems comprising well defined artificial secondary structures [2], with the potential to transmit chiral information from the outer-coordination sphere to the prochiral catalytically active metal centre. "backdoor induction" L R* L R* L R* Mct Mct L R* prochiral metal chiral substituents Figure 1: Side view and top view of a supramolecular transition metal catalyst (minimal artificial enzyme). The arrows indicate the sign of the helical chirality. References [1] (a) Z. Kokan, B. Perić, M. Vazdar, Ž. Marinić, D. Vikić-Topić, E. Meštrović, S. I. Kirin, Chem. Commun., 53 (2017) 1945-1948; (b) Đ. Škalamera, E. Sanders, R. Vianello, A. Maršavelski, A. Pevec, I. Turel, S. I. Kirin, Dalton Trans., 45 (2016) 2845-2858; (c) Z. Kokan, Z. Glasovac, M. Majerić Elenkov, M. Gredičak, I. Jerić, S. I. Kirin, Organometallics, 33 (2014) 4005-4015; (d) Z. Kokan, S. I. Kirin, Eur. J. Org. Chem., (2013) 8154-8161; (e) Z. Kokan, S. I. Kirin, RSC Adv., 2 (2012) 5729-5737. [2] S. I. Kirin, H.-B. Kraatz, N. Metzler-Nolte, Chem. Soc. Rev., 35 (2006) 348-354.