Journal article
Catalytic Kinetic Resolution by Enantioselective Aromatization: Conversion of Racemic Intermediates of the Barton-Zard Reaction into Enantioenriched 3-Arylpyrroles.
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Zheng SC
Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, 1015, Lausanne, Switzerland.
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Wang Q
Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, 1015, Lausanne, Switzerland.
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Zhu J
Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, 1015, Lausanne, Switzerland.
Published in:
- Angewandte Chemie (International ed. in English). - 2019
English
Racemic 3,4-dihydro-2H-pyrroles, hypothetical intermediates of the Barton-Zard reaction, were synthesized in a highly diastereoselective manner and fully characterized for the first time. Kinetic resolution of the dihydropyrroles with a quinine-derived thiourea afforded the (+)-3-arylpyrrole products and recovered (+)-3,4-dihydro-2H-pyrroles with high efficiency (s-factor up to 153). The resolved (+)-3,4-dihydro-2H-pyrroles underwent subsequent aromatization with a quinidine-derived thiourea catalyst to afford (-)-3-arylpyrroles with excellent central-to-axial chirality transfer. In contrast to the well-accepted Barton-Zard mechanism, the aromatization of the 3,4-dihydro-2H-pyrroles in the presence of a bifunctional catalyst is believed to proceed by an unprecedented sequence involving syn elimination of HNO2 and aromatization.
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Language
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Open access status
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closed
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Identifiers
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Persistent URL
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https://folia.unifr.ch/global/documents/211300
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