Access to Chiral GABA Analogues Bearing a Trifluoromethylated All-Carbon Quaternary Stereogenic Center through Water-Promoted Organocatalytic Michael Reactions
journal contributionposted on 2019-08-16, 16:06 authored by Jae Hun Sim, Jin Hyun Park, Pintu Maity, Choong Eui Song
Water enables the highly challenging enantioselective Michael addition of sterically congested β-trifluoromethyl-β-aryl- or -alkyl-substituted nitroolefins with dithiomalonates. Under on-water conditions, the reaction rates were remarkably accelerated as a result of enforced hydrophobic interactions between catalysts and reactants. Takemoto-type thiourea catalysts are very effective for this transformation, affording highly enantioenriched Michael adducts that provide simple access to chiral γ-aminobutyric acid (GABA) analogues with a β-trifluoromethylated quaternary stereocenter.
β- trifluoromethylated quaternary stereocenterTakemoto-type thiourea catalystsreaction ratesChiral GABA Analogues Bearingchiral γ- aminobutyric acidTrifluoromethylated All-Carbon Quaternary Stereogenic Centerenantioenriched Michael adductsenantioselective Michael additionon-water conditionsalkyl-substituted nitroolefinsWater-Promoted Organocatalytic Michael Reactions Waterβ- trifluoromethyl -β-aryl