**Author details**

this solution is economically acceptable). Increasing the reaction temperature is, however, not the optimal solution, since enantioselectivity is decreasing with a higher temperature. Eliminating metal residues from the product is not an issue in these days as applying commercially

In 1997, Avencia Company patented rhodium catalysts bearing diamine, aminoalcohol ligands, respectively, for asymmetric transfer hydrogenation of imines and ketones. These Rh complexes are analogues to original Noyori's ruthenium catalysts. However, except for the central atom, these catalysts also differ in their aromatic ligand, which is in the most cases η5

pentamethylcyclopentadienyl. These catalysts are used for the production of several different types of chiral alcohols and amines. To name some examples, one of the running processes is ATH of tetralone to (*R*)-1-tetralol with the capacity of 200 dm3 and the corresponding yield of 95 and 97% *ee*, than the process of preparation of (*S*)-1-(4-flurophenyl)ethanol with its yield of 85 and 98.4% *ee* or the production of (*R*)-N-diphenylphosphinyl-1-methylamine with 95%

Asymmetric transfer hydrogenation has the potential to find use also in the production of fine chemicals such as drugs, where a high optical purity of the final products is demanded. To provide an example, the preparation of the precursor for the synthesis of muscle relaxant, mivacurium-chloride, can be mentioned [27]. In this case, the application of ATH for the preparation of mivacurium-chloride seems to be a more favorable, since the cleavage used in the classical preparation, capitalizing on using *L*-dibenzoyltartaric acid to separate both

The main purpose of this study was to describe selected parts of the asymmetric transfer hydrogenation of ketones and particularly imines. Our attention was predominantly aimed to the importance of the mechanistic aspects of the ATH or structural effects influencing the reaction course. All parts of this work show that the asymmetric transfer hydrogenation is the

This work was realized within the Operational Program Prague – Competitiveness (CZ. 2.16/3.1.00/22197) and "National Program of Sustainability" (NPU I LO1215) MSMT - 34870/2013); The Operational Program Prague–Competitiveness (CZ.2.16/3.1.00/21537) and "National Program of Sustainability" (NPU I LO1601) MSMT-43760/2015); The Operational Program Prague–Competitiveness (CZ.2.16/3.1.00/24501) and "National Program of Sustaina-

available methods allows reducing the number of residues to units of *ppm*.

52 New Advances in Hydrogenation Processes - Fundamentals and Applications

enantiomers, is rather ineffective and produce a lot of nonrecyclable waste.

reaction which can find its use across all branches of the chemical industry.

bility" (NPU I LO1613) MSMT-43760/2015) and GACR (GA15-08992S).

yield and 99% *ee* [26].

**7. Conclusion**

**Acknowledgements**

Ondřej Matuška, Martin Kindl and Petr Kačer\*

\*Address all correspondence to: kacerp@vscht.cz

University of Chemistry and Technology (UCT Prague), Prague, Czech Republic
