A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of ( S )-baclofen.

Autor:	Dargó G; Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary., Erdélyi D; Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary., Molnár B; Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary., Kisszékelyi P; Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary., Garádi Z; Department of Pharmacognosy, Semmelweis University, Üllői út. 26, H-1085 Budapest, Hungary., Kupai J; Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary.
Jazyk:	angličtina
Zdroj:	Beilstein journal of organic chemistry [Beilstein J Org Chem] 2023 Nov 24; Vol. 19, pp. 1811-1824. Date of Electronic Publication: 2023 Nov 24 (Print Publication: 2023).
DOI:	10.3762/bjoc.19.133
Abstrakt:	Synthesizing organocatalysts is often a long and cost-intensive process, therefore, the recovery and reuse of the catalysts are particularly important to establish sustainable organocatalytic transformations. In this work, we demonstrate the synthesis, application, and recycling of a new lipophilic cinchona squaramide organocatalyst. The synthesized lipophilic organocatalyst was applied in Michael additions. The catalyst was utilized to promote the Michael addition of cyclohexyl Meldrum's acid to 4-chloro- trans -β-nitrostyrene (quantitative yield, up to 96% ee). Moreover, 1 mol % of the catalyst was feasible to conduct the gram-scale preparation of baclofen precursor (89% yield, 96% ee). Finally, thanks to the lipophilic character of the catalyst, it was easily recycled after the reaction by replacing the non-polar reaction solvent with a polar solvent, acetonitrile, with 91-100% efficiency, and the catalyst was reused in five reaction cycles without the loss of activity and selectivity. (Copyright © 2023, Dargó et al.)
Databáze:	MEDLINE
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