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

Autor:	Lin Y; Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States.; Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States., Hirschi WJ; Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States., Kunadia A; Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States., Paul A; Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States.; Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States., Ghiviriga I; Center for NMR Spectroscopy, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States., Abboud KA; Center for X-ray Crystallography, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States., Karugu RW; Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States., Vetticatt MJ; Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States., Hirschi JS; Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States., Seidel D; Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States.; Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States.
Jazyk:	angličtina
Zdroj:	Journal of the American Chemical Society [J Am Chem Soc] 2020 Mar 25; Vol. 142 (12), pp. 5627-5635. Date of Electronic Publication: 2020 Mar 11.
DOI:	10.1021/jacs.9b12457
Abstrakt:	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 13 C 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.
Databáze:	MEDLINE
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