Enantioselective Distal Functionalization of 3-Cyano-4-methylcoumarins through Direct Vinylogous Conjugate Addition to Maleimides
Sanjay Singh, Ravi Saini, Ravi P. Singh
Abstract
An unprecedented organocatalyzed asymmetric vinylogous Michael reaction between 3-cyano-4-methylcoumarins and maleimides with an excellent enantiomeric ratio (up to 99.5:0.5) and yield (up to 95%) is reported. This remarkable selectivity is attributed to the hydrogen bonding ability of l-tert-leucine-derived amine thiourea catalyst. The versatility, practical applicability, and scalability are demonstrated by the generation of γ-functionalized coumarin derivatives.
Topics & Concepts
Enantioselective synthesisThioureaSurface modificationChemistryYield (engineering)ConjugateSelectivityAmine gas treatingCoumarinCatalysisEnantiomerMichael reactionCombinatorial chemistryOrganocatalysisHydrogen bondOrganic chemistryMathematicsMaterials scienceMoleculeMetallurgyMathematical analysisPhysical chemistryAsymmetric Synthesis and CatalysisAxial and Atropisomeric Chirality SynthesisSynthesis and Biological Activity