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A Selenourea-Thiourea Bronsted Acid Catalyst Facilitates Asymmetric Conjugate Additions of Amines to ?,?-Unsaturated Esters.

ABSTRACT: ?-Amino esters are obtained with high levels of enantioselectivity via the conjugate addition of cyclic amines to unactivated ?,?-unsaturated esters. A related strategy enables the kinetic resolution of racemic cyclic 2-arylamines, using benzyl acrylate as the resolving agent. Reactions are facilitated by an unprecedented selenourea-thiourea organocatalyst. As elucidated by DFT calculations and 13C kinetic isotope effect studies, the rate-limiting and enantiodetermining step of the reaction is the protonation of a zwitterionic intermediate by the catalyst. This represents a rare case in which a thiourea compound functions as an asymmetric Brønsted acid catalyst.

SUBMITTER: Lin Y

PROVIDER: S-EPMC7533150 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature

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A Selenourea-Thiourea Brønsted Acid Catalyst Facilitates Asymmetric Conjugate Additions of Amines to α,β-Unsaturated Esters.

Lin Yingfu Y Hirschi William J WJ Kunadia Anuj A Paul Anirudra A Ghiviriga Ion I Abboud Khalil A KA Karugu Rachael W RW Vetticatt Mathew J MJ Hirschi Jennifer S JS Seidel Daniel D

Journal of the American Chemical Society 20200311 12

β-Amino esters are obtained with high levels of enantioselectivity via the conjugate addition of cyclic amines to unactivated α,β-unsaturated esters. A related strategy enables the kinetic resolution of racemic cyclic 2-arylamines, using benzyl acrylate as the resolving agent. Reactions are facilitated by an unprecedented selenourea-thiourea organocatalyst. As elucidated by DFT calculations and <sup>13</sup>C kinetic isotope effect studies, the rate-limiting and enantiodetermining step of the re ...[more]

PMID: 32118419

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