A Robust Heterogeneous Chiral Phosphoric Acid Enables Multi Decagram Scale Production Of Optically Active N, S-Ketals

22 January 2024, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Asymmetric organocatalysis has been recognized as one of the Top 10 Emerging Technologies in Chemistry by the IUPAC in 2019. Its potential to make chemical processes more sustainable is promising, but there are still challenges that need to be addressed. Developing new and reliable enantioselective processes for reproducing batch reactions on a large scale requires a combination of chemical and technical solutions. In this manuscript, we combine a robust immobilized chiral phosphoric acid with a new packed-bed reactor design. This combination allows scaling up the enantioselective addition of thiols to imines from a few milligrams to a multi-decagram scale in a continuous flow process without physical or chemical degradation of the catalyst.


Asymmetric catalysis
chiral phosphoric acid
heterogeneous catalysis
continuous flow

Supplementary materials

Experimental supplementary material
General experimental procedures. Characterization of organic compounds and catalyst. Reactor design.


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