thiourea and diethyl-malonate

The mechanism of the enantioselective Michael addition of diethyl malonate to trans-β-nitrostyrene catalyzed by a tertiary amine thiourea organocatalyst is explored using experimental 13C kinetic isotope effects and density functional theory calculations. Large primary 13C KIEs on the bond-forming carbon atoms of both reactants suggest that carbon-carbon bond formation is the rate-determining step in the catalytic cycle. This work resolves conflicting mechanistic pictures that have emerged from prior experimental and computational studies.

Topics: Catalysis; Density Functional Theory; Malonates; Molecular Structure; Stereoisomerism; Styrenes; Thiourea

Chalcones are still challenge substrates in Michael reactions, and only limited success has been achieved. This work describes a highly enantioselective Michael addition of diethyl malonate with chalcones catalyzed by cinchona alkaloids-derivatived bifunctional tertiary amine-thioureas bearing multiple hydrogen-bonding donors.

Topics: Amines; Catalysis; Chalcones; Cinchona Alkaloids; Hydrogen Bonding; Malonates; Stereoisomerism; Temperature; Thiourea