Green asymmetric organocatalysis

Radovan Šebesta / Comenius University in Bratislava

March 11, 2021, 2 - 3 pm CET

Online live talk

Introduction

Current environmental challenges and the longstanding need for chiral compounds pose new demands on organic syntheses. Effective syntheses of chiral compounds necessary for medicines, materials, or crop protection must fulfill, besides high stereoselectivity, stringent environmental criteria. Asymmetric organocatalyses offer great opportunities in the synthesis of important chiral compounds and at the same time enable implementation of green chemistry principles.

Various enantioselective organocatalytic reactions, such as Michael additions of aldehydes to nitroalkenes, aminoxylation, and hydrazination of aldehydes can be performed in aqueous media or under solventless conditions using a ball mill. We have found out that these reactions proceed with high yields and highly enantioselective. The solventless methodology also allows more effective catalysis using organocatalysts, which employ non-covalent interactions for activation. Chiral thioureas and squaramides proved to be more enantioselective catalysts for Michael additions and domino Mannich/fluorination reactions under solventless conditions than in solvents. The in-situ release of unstable alkyloxyacetaldehydes from acetals using acidic ionic liquids and microwave irradiation improved the organocatalytic synthesis of antiviral drug oseltamivir. Greener solvent alternatives, such as 2-methyltetrahydrofurane allow highly enantioselective warfarin synthesis.

Radovan Šebesta

Radovan Šebesta studied chemistry at the Comenius University in Bratislava, where he obtained his PhD under the guidance of Professor Marta Sališová. During his postdoctoral stay with Professor Dieter Seebach at the ETH Zurich, he studied β-amino acids and peptides. Then, he worked with Professor Ben Feringa in Groningen on Cu-catalyzed conjugate additions. In 2005, he returned to Comenius University where he is now a full Professor of Organic Chemistry. His research interests are new methodologies in asymmetric catalysis using organometallic reagents and catalysts, green chemistry methodologies as well as organocatalytic syntheses of biorelevant compounds.

Radovan Šebesta is guest editor of the thematic issue "New advances in asymmetric organocatalysis" in the Beilstein Journal of Organic Chemistry.

Contact

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