s-Block Metal-Mediated Hydroelementation
Recruting institution: UAB
Diploma-delivering institutions: UAB, FSU
Thesis co-directors: Agustí Lledós (UAB, Barcelona, ES), Matthias Westerhausen (FSU, Jena, DE)
Secondment host: Italmatch Chemicals (IT)
The addition of H-E bonds of amines (hydroamination), phosphanes (hydrophosphanylation), and phosphane oxides (hydrophosphorylation) to multiple bonds (e.g. alkynes) represents an atom-economic reaction that requires a catalyst. s-Block metal complexes are able to promote these addition reactions regioselectively with a significantly increased reactivity for heterobimetallic catalysts (e.g. mixed K/Ca complexes). However, stereocontrol as well as steric and electronic control remain challenging tasks. This project targets mechanistic studies to elucidate not only intermediates but obstacles during the catalytic H-E bond addition across unsaturated substrates to clarify the mode of action for the alkali and alkaline earth metalions.
 S. M. Härling, B. E. Fener, S. Krieck, H. Görls, M. Westerhausen, Organometallics2018, 37, 4380-4386. S. Ziemann, S. Krieck, H. Görls, M. Westerhausen, Organometallics2018, 37, 924-933. S. M. Härling, S. Krieck, H. Görls, M. Westerhausen, Inorg. Chem. 2017, 56, 9255-9263. F. M. Younis, S. Krieck, T. M. A. Al-Shboul, H. Görls, M. Westerhausen, Inorg. Chem. 2016, 55, 4676-4682.
 A. Couce-Rios, A. Lledós, G. Ujaque, Chem. Eur. J.2016, 22, 9311 – 9320.
Addition of H-E bonds across alkynes leads to E/Z-isomeric mixtures. In this project stereocontrol of the s-block metal-mediated addition of H-E-containing substrates onto alkynes with > 95 % of E– or Z-isomeric products will be achieved with catalyst loadings between 2-5 mol-%. Quantum chemical studies will allow to elucidate the influence of the nature of the s-block metal ions (charge, hardness, radius, polarizability) on the energy values of the transition states and hence on the mechanism of the catalytic cycle. We also envision a stereoselective intramolecular hydroelementation of alkenes with ee > 95 %.