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Biswas A. Organocatalyzed Asymmetric Pictet‐Spengler Reactions. ChemistrySelect 2023. [DOI: 10.1002/slct.202203368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Anup Biswas
- Departmentof Chemistry Hooghly Women's College Vivekanada Road, Pipulpati Hooghly 712102 India
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Andres R, Sun F, Wang Q, Zhu J. Organocatalytic Enantioselective Pictet-Spengler Reaction of α-Ketoesters: Development and Application to the Total Synthesis of (+)-Alstratine A. Angew Chem Int Ed Engl 2023; 62:e202213831. [PMID: 36347809 DOI: 10.1002/anie.202213831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Indexed: 11/10/2022]
Abstract
We report herein an asymmetric Pictet-Spengler reaction of α-ketoesters. In the presence of a catalytic amount of simple alanine-derived squaramide and p-nitrobenzoic acid, reaction of tryptamines with methyl 2-oxoalkanoates afforded the corresponding 1-alkyl-1-methoxycarbonyl tetrahydro-β-carbolines (THBCs) in high yields and ee values. A primary kinetic isotope effect (KIE=4.5) using C2-deteurium-labelled tryptamine indicates that rearomatization through deprotonation of the pentahydro-β-carbolinium ion could be the rate- and enantioselectivity-determining step. A concise enantioselective total synthesis of (+)-alstratine A, a hexacyclic cagelike monoterpene indole alkaloid, featuring this reaction as a key step, was subsequently accomplished. Remeasurement of the [a]D value of the natural product indicates that natural alstratine A is dextrorotatory rather than levorotatory as it was initially reported in the isolation paper.
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Affiliation(s)
- Rémi Andres
- Laboratory of Synthesis and Natural Products (LSPN), Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH, 5304, 1015, Lausanne, Switzerland
| | - Fenggang Sun
- Laboratory of Synthesis and Natural Products (LSPN), Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH, 5304, 1015, Lausanne, Switzerland.,School of Chemical Engineering, Shandong University of Technology, Zibo, 255049, P. R. China
| | - Qian Wang
- Laboratory of Synthesis and Natural Products (LSPN), Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH, 5304, 1015, Lausanne, Switzerland
| | - Jieping Zhu
- Laboratory of Synthesis and Natural Products (LSPN), Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH, 5304, 1015, Lausanne, Switzerland
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Andres R, Wang Q, Zhu J. Catalytic Enantioselective Pictet-Spengler Reaction of α-Ketoamides Catalyzed by a Single H-Bond Donor Organocatalyst. Angew Chem Int Ed Engl 2022; 61:e202201788. [PMID: 35225416 PMCID: PMC9313548 DOI: 10.1002/anie.202201788] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Indexed: 01/17/2023]
Abstract
The asymmetric Pictet–Spengler reaction (PSR) with aldehydes is well known. However, PSR involving ketones as electrophilic partners is far‐less developed. We report herein the first examples of catalytic enantioselective PSR of tryptamines with α‐ketoamides. A new class of easily accessible prolyl‐urea organocatalysts bearing a single H‐bond donor function catalyzes the title reaction to afford 1,1‐disubstituted tetrahydro‐β‐carbolines in excellent yields and enantioselectivities. The kinetic isotope effect using C2‐deuterium‐labelled tryptamine indicates that the rearomatization of the pentahydro‐β‐carbolinium ion intermediate might be the rate‐ and the enantioselectivity‐determining step.
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Affiliation(s)
- Rémi Andres
- Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH, 5304, 1015, Lausanne, Switzerland
| | - Qian Wang
- Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH, 5304, 1015, Lausanne, Switzerland
| | - Jieping Zhu
- Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH, 5304, 1015, Lausanne, Switzerland
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Andres R, Wang Q, Zhu J. Catalytic Enantioselective Pictet–Spengler Reaction of α‐Ketoamides Catalyzed by a Single H‐Bond Donor Organocatalyst. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202201788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Rémi Andres
- Laboratory of Synthesis and Natural Products Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, 1015 Lausanne Switzerland
| | - Qian Wang
- Laboratory of Synthesis and Natural Products Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, 1015 Lausanne Switzerland
| | - Jieping Zhu
- Laboratory of Synthesis and Natural Products Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, 1015 Lausanne Switzerland
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