Diastereo‐ and Enantioselective Organocatalytic Synthesis of Spirocyclopropyl Pyrazolones
Laura Carceller‐Ferrer, Gonzalo Blay, M. Carmen Muñoz, José R. Pedro, Carlos Vila
Abstract
Abstract A diastereo‐ and enantioselective synthesis of spirocyclopropylpyrazolones has been described through a Michael/alkylation cascade reaction of 4‐arylidenepyrazol‐5‐ones with diethyl 2‐bromomalonate catalyzed by (DHQ) 2 AQN. The reaction afforded selectively the corresponding spirocyclic compounds with 30–83% yield, diastereoselectivities ranging from 60:40 to >95:5 and 26–93% enantiomeric excess under mild reaction conditions. Moreover, we performed two selective transformations with the corresponding chiral compounds.
Topics & Concepts
Enantioselective synthesisChemistryPyrazolonesYield (engineering)AlkylationEnantiomeric excessEnantiomerCascade reactionOrganic chemistryOrganocatalysisCatalysisStereochemistryMaterials scienceMetallurgyCyclopropane Reaction MechanismsCatalytic C–H Functionalization MethodsAsymmetric Synthesis and Catalysis