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Transition state analysis of enantioselective Brønsted base catalysis by chiral cyclopropenimines.

Bandar JS, Sauer GS, Wulff WD, Lambert TH, Vetticatt MJ - J. Am. Chem. Soc. (2014)

Bottom Line: Experimental (13)C kinetic isotope effects have been used to interrogate the rate-limiting step of the Michael addition of glycinate imines to benzyl acrylate catalyzed by a chiral 2,3-bis(dicyclohexylamino) cyclopropenimine catalyst.The reaction is found to proceed via rate-limiting carbon-carbon bond formation.The origins of enantioselectivity and a key noncovalent CH···O interaction responsible for transition state organization are identified on the basis of density functional theory calculations and probed using experimental labeling studies.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Columbia University , 3000 Broadway, New York, New York 10027, United States.

ABSTRACT
Experimental (13)C kinetic isotope effects have been used to interrogate the rate-limiting step of the Michael addition of glycinate imines to benzyl acrylate catalyzed by a chiral 2,3-bis(dicyclohexylamino) cyclopropenimine catalyst. The reaction is found to proceed via rate-limiting carbon-carbon bond formation. The origins of enantioselectivity and a key noncovalent CH···O interaction responsible for transition state organization are identified on the basis of density functional theory calculations and probed using experimental labeling studies. The resulting high-resolution experimental picture of the enantioselectivity-determining transition state is expected to guide new catalyst design and reaction development.

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Chiral Brønsted Base-Catalyzed MichaelAddition of Glycine Imineto Acrylates
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Transition state analysis of enantioselective Brønsted base catalysis by chiral cyclopropenimines.

Bandar JS, Sauer GS, Wulff WD, Lambert TH, Vetticatt MJ - J. Am. Chem. Soc. (2014)

Chiral Brønsted Base-Catalyzed MichaelAddition of Glycine Imineto Acrylates
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230825&req=5

sch1: Chiral Brønsted Base-Catalyzed MichaelAddition of Glycine Imineto Acrylates
Bottom Line: Experimental (13)C kinetic isotope effects have been used to interrogate the rate-limiting step of the Michael addition of glycinate imines to benzyl acrylate catalyzed by a chiral 2,3-bis(dicyclohexylamino) cyclopropenimine catalyst.The reaction is found to proceed via rate-limiting carbon-carbon bond formation.The origins of enantioselectivity and a key noncovalent CH···O interaction responsible for transition state organization are identified on the basis of density functional theory calculations and probed using experimental labeling studies.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Columbia University , 3000 Broadway, New York, New York 10027, United States.

ABSTRACT
Experimental (13)C kinetic isotope effects have been used to interrogate the rate-limiting step of the Michael addition of glycinate imines to benzyl acrylate catalyzed by a chiral 2,3-bis(dicyclohexylamino) cyclopropenimine catalyst. The reaction is found to proceed via rate-limiting carbon-carbon bond formation. The origins of enantioselectivity and a key noncovalent CH···O interaction responsible for transition state organization are identified on the basis of density functional theory calculations and probed using experimental labeling studies. The resulting high-resolution experimental picture of the enantioselectivity-determining transition state is expected to guide new catalyst design and reaction development.

Show MeSH