Hybrid Peptide–Thiourea Catalyst for Asymmetric Michael Additions of Aldehydes to Heterocyclic Nitroalkenes
Patrícia Čmelová, Denisa Vargová, Radovan Šebesta
Abstract
Bifunctional organocatalysis combining covalent and noncovalent activation is presented. The hybrid peptide–thiourea catalyst features a N-terminal proline moiety for aldehyde activation and a thiourea unit for electrophile activation. This catalyst effectively promotes asymmetric Michael additions of aldehydes to challenging but biologically relevant heterocycle-containing nitroalkenes. The catalyst can be used under solvent-free conditions. Spectroscopic and density functional theory studies elucidate the catalyst structure and mode of action.
Topics & Concepts
ThioureaMoietyBifunctionalOrganocatalysisMichael reactionChemistryAldehydeCatalysisElectrophileCombinatorial chemistryOrganic chemistrySquaramideCovalent bondAldol reactionEnantioselective synthesisAsymmetric Synthesis and CatalysisChemical Synthesis and AnalysisChemical Synthesis and Reactions