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A Computational Study of the Origin of Stereoinduction in NHC-Catalyzed Annulation Reactions of ?,?-Unsaturated Acyl Azoliums.

ABSTRACT: The origin of stereoselectivity of NHC-catalyzed annulation reactions of ynals and stable enols was studied with Density Functional Theory. The data suggest that the C-C bond formation is the stereo-determining step. Only the deprotonated pathway (containing an oxy anion and overall neutral species) was found to give rise to discrimination of the competing stereoisomers. This is due predominantly to electrostatic repulsion of the ?-stabilizing enolate functionality with the ?-cloud of the aryl group in the NHC-catalyst.

SUBMITTER: Lyngvi E

PROVIDER: S-EPMC3655779 | biostudies-literature | 2012 Mar

REPOSITORIES: biostudies-literature

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A Computational Study of the Origin of Stereoinduction in NHC-Catalyzed Annulation Reactions of α,β-Unsaturated Acyl Azoliums.

Lyngvi Eirik E Bode Jeffrey W JW Schoenebeck Franziska F

Chemical science 20120301 3

The origin of stereoselectivity of NHC-catalyzed annulation reactions of ynals and stable enols was studied with Density Functional Theory. The data suggest that the C-C bond formation is the stereo-determining step. Only the deprotonated pathway (containing an oxy anion and overall neutral species) was found to give rise to discrimination of the competing stereoisomers. This is due predominantly to electrostatic repulsion of the β-stabilizing enolate functionality with the π-cloud of the aryl g ...[more]

PMID: 23687566

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