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Org Biomol Chem
; 17(16): 3934-3939, 2019 04 17.
Article
in English
| MEDLINE
| ID: mdl-30942247
ABSTRACT
The mechanism of the enantioselective Michael addition of diethyl malonate to trans-ß-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.