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Transition state analysis of an enantioselective Michael addition by a bifunctional thiourea organocatalyst.

ABSTRACT: The mechanism of the enantioselective Michael addition of diethyl malonate to trans-?-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.

SUBMITTER: Izzo JA

PROVIDER: S-EPMC6774437 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature

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Transition state analysis of an enantioselective Michael addition by a bifunctional thiourea organocatalyst.

Izzo Joseph A JA Myshchuk Yaroslaw Y Hirschi Jennifer S JS Vetticatt Mathew J MJ

Organic & biomolecular chemistry 20190401 16

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 ...[more]

PMID: 30942247

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