1
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Mousavi M, Di Mola A, Pierri G, Tedesco C, Hensinger MJ, Sun A, Wang Y, Mayer P, Ofial AR, Massa A. Lactone Enolates of Isochroman-3-ones and 2-Coumaranones: Quantification of Their Nucleophilicity in DMSO and Conjugate Additions to Chalcones. J Org Chem 2024; 89:6915-6928. [PMID: 38687827 PMCID: PMC11110064 DOI: 10.1021/acs.joc.4c00277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/28/2024] [Accepted: 04/06/2024] [Indexed: 05/02/2024]
Abstract
Owing to stereoelectronic effects, lactones often deviate in reactivity from their open-chain ester analogues as demonstrated by the CH acidity (in DMSO) of 3-isochromanone (pKa = 18.8) and 2-coumaranone (pKa = 13.5), which is higher than that of ethyl phenylacetate (pKa = 22.6). We have now characterized the reactivity of the lactone enolates derived from 3-isochromanone and 2-coumaranone by following the kinetics of their Michael reactions with p-quinone methides and arylidenemalonates (reference electrophiles) in DMSO at 20 °C. Evaluation of the experimentally determined second-order rate constants k2 by the Mayr-Patz equation, lg k2 = sN(N + E), furnished the nucleophilicity parameters N (and sN) of the lactone enolates. By localizing their position on the Mayr nucleophilicity scale, the scope of their electrophilic reaction partners becomes predictable, and we demonstrate a novel catalytic methodology for a series of carbon-carbon bond-forming reactions of lactone enolates with chalcones under phase transfer conditions in toluene.
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Affiliation(s)
- Mohammad
Sadeq Mousavi
- Dipartimento
di Chimica e Biologia “A. Zambelli”, Università degli Studi di Salerno, Via Giovanni Paolo II, 84084 Fisciano, SA, Italy
| | - Antonia Di Mola
- Dipartimento
di Chimica e Biologia “A. Zambelli”, Università degli Studi di Salerno, Via Giovanni Paolo II, 84084 Fisciano, SA, Italy
| | - Giovanni Pierri
- Dipartimento
di Chimica e Biologia “A. Zambelli”, Università degli Studi di Salerno, Via Giovanni Paolo II, 84084 Fisciano, SA, Italy
| | - Consiglia Tedesco
- Dipartimento
di Chimica e Biologia “A. Zambelli”, Università degli Studi di Salerno, Via Giovanni Paolo II, 84084 Fisciano, SA, Italy
| | - Magenta J. Hensinger
- Department
Chemie, Ludwig-Maximilians-Universität
München, Butenandtstr. 5-13, 81377 München, Germany
| | - Aijia Sun
- Department
Chemie, Ludwig-Maximilians-Universität
München, Butenandtstr. 5-13, 81377 München, Germany
| | - Yilan Wang
- Department
Chemie, Ludwig-Maximilians-Universität
München, Butenandtstr. 5-13, 81377 München, Germany
| | - Peter Mayer
- Department
Chemie, Ludwig-Maximilians-Universität
München, Butenandtstr. 5-13, 81377 München, Germany
| | - Armin R. Ofial
- Department
Chemie, Ludwig-Maximilians-Universität
München, Butenandtstr. 5-13, 81377 München, Germany
| | - Antonio Massa
- Dipartimento
di Chimica e Biologia “A. Zambelli”, Università degli Studi di Salerno, Via Giovanni Paolo II, 84084 Fisciano, SA, Italy
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2
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Xiong TZ, Yisimayili N, Lu CD. Stereoselective Electrophilic Chlorination of β,β-Disubstituted Enesulfinamides with Chloramine-T: Asymmetric Synthesis of Acyclic α,α-Disubstituted α-Chlorinated Carbonyl Surrogates. Org Lett 2024; 26:1851-1856. [PMID: 38386702 DOI: 10.1021/acs.orglett.4c00059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
Enamine and iminium ion-mediated asymmetric organocatalysis was not successful in achieving highly stereoselective α-chlorination of acyclic α,α-disubstituted carbonyls. To address this limitation, an alternative method was developed, which involved the use of geometry-defined persubstituted enesulfinamides to intercept the electrophilic chlorinating reagent. This approach enables the asymmetric construction of challenging acyclic α,α-disubstituted α-chlorinated ketimines with a high degree of stereoselectivity. The use of chloramine-T, a cost-effective and stable chlorine source rarely utilized in asymmetric electrophilic chlorination, plays a crucial role in achieving superior stereocontrol.
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Affiliation(s)
- Teng-Zhao Xiong
- School of Chemical Science and Technology, Yunnan University, Kunming, Yunnan 650091, China
| | | | - Chong-Dao Lu
- School of Chemical Science and Technology, Yunnan University, Kunming, Yunnan 650091, China
- School of Health, Jiangxi Normal University, Nanchang, Jiangxi 330022, China
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3
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Piringer M, Stockhammer L, Vogl L, Weinzierl D, Zebrowski P, Waser M. Enantioselective α-heterofunctionalization reactions of catalytically generated C1-Lewis base enolates. TETRAHEDRON CHEM 2024; 9:100063. [PMID: 38846753 PMCID: PMC7616070 DOI: 10.1016/j.tchem.2024.100063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/09/2024]
Abstract
Chiral Lewis base (LB) organocatalysis has emerged as a powerful covalent catalysis concept which allows for highly selective asymmetric C-C and C-heteroatom bond formations. Considering significant recent progress in the development of strategies to access α-heterofunctionalized carboxylic acid derivatives under chiral LB catalysis, we wish to summarize the most significant concepts and advances in this field within this mini review now.
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Affiliation(s)
| | | | | | | | | | - Mario Waser
- Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstr. 69, 4040 Linz, Austria
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4
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Li Z, Wang B, Zhang C, Lo WY, Yang L, Sun J. Catalytic Enantioselective Nucleophilic α-Chlorination of Ketones with NaCl. J Am Chem Soc 2024; 146:2779-2788. [PMID: 38238317 DOI: 10.1021/jacs.3c12826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Catalytic enantioselective α-chlorination of ketones is a highly desirable process. Different from the conventional approaches that employ corrosive electrophilic chlorination reagents, the process disclosed here employs nucleophilic chloride, aqueous NaCl solution, and even seawater, as green inexpensive chlorine sources. This mechanistically distinct and electronically opposite approach provides facile access to diverse highly enantioenriched acyclic α-chloro ketones that are less straightforward by conventional approaches. With a chiral thiourea catalyst, a range of racemic α-keto sulfonium salts underwent enantioconvergent carbon-chlorine bond formation with high efficiency and excellent enantioselectivity under mild conditions. The sulfonium motif plays a crucial triple role by permitting smooth dynamic kinetic resolution to take place via a chiral anion binding mechanism in a well-designed phase-transfer system. This protocol represents a new general platform for the asymmetric nucleophilic α-functionalization of carbonyl compounds.
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Affiliation(s)
- Zhiyang Li
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong SAR 999077, China
- Shenzhen Research Institute, HKUST, No. 9 Yuexing First Rd, Shenzhen 518057, China
| | - Baocheng Wang
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong SAR 999077, China
| | - Chaoshen Zhang
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong SAR 999077, China
| | - Wai Yam Lo
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong SAR 999077, China
| | - Liangliang Yang
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong SAR 999077, China
| | - Jianwei Sun
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong SAR 999077, China
- Shenzhen Research Institute, HKUST, No. 9 Yuexing First Rd, Shenzhen 518057, China
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5
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Zebrowski P, Monkowius U, Waser M. Cooperative Chiral Lewis Base/Palladium-Catalyzed Asymmetric Syntheses of Methylene-Containing δ-Lactams. European J Org Chem 2023; 26:e202300982. [PMID: 38601429 PMCID: PMC11005102 DOI: 10.1002/ejoc.202300982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/19/2023] [Indexed: 04/12/2024]
Abstract
We herein report a two-step approach for the enantioselective synthesis of novel chiral δ-lactams. By using a cooperative chiral ITU/achiral Pd-catalyst system, this protocol proceeds via an asymmetric α-allylation of activated aryl esters first, followed by an acid-mediated lactam formation. A variety of differently substituted products could be obtained with usually high levels of enantioselectivities and in reasonable yields (16 examples, up to 98 : 2 er and 73 % yield over two steps). In addition, further utilizations of the products via transformations of the exocyclic double bond were successfully carried out as well.
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Affiliation(s)
- Paul Zebrowski
- Institute of Organic ChemistryJohannes Kepler University LinzAltenbergerstrasse 694040LinzAustria
| | - Uwe Monkowius
- School of EducationChemistryJohannes Kepler University LinzAltenbergerstrasse 694040LinzAustria
| | - Mario Waser
- Institute of Organic ChemistryJohannes Kepler University LinzAltenbergerstrasse 694040LinzAustria
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6
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Stockhammer L, Radetzky M, Khatoon SS, Bechmann M, Waser M. Chiral Lewis Base-Catalysed Asymmetric Syntheses of Benzo-fused ϵ-Lactones. European J Org Chem 2023; 26:e202300704. [PMID: 38601860 PMCID: PMC11005097 DOI: 10.1002/ejoc.202300704] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/24/2023] [Indexed: 04/12/2024]
Abstract
We herein report a two-step protocol for the asymmetric synthesis of novel chiral benzofused ϵ-lactones starting from O-protected hydroxymethyl-para-quinone methides and activated aryl esters. By using chiral isothiourea Lewis base catalysts a broad variety of differently substituted products could be obtained in yields of around 50 % over both steps with high levels of enantioselectivities, albeit low diastereoselectivities only.
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Affiliation(s)
- Lotte Stockhammer
- Institute of Organic ChemistryJohannes Kepler University LinzAltenbergerstrasse 694040LinzAustria
| | - Maximilian Radetzky
- Institute of Organic ChemistryJohannes Kepler University LinzAltenbergerstrasse 694040LinzAustria
| | - Syeda Sadia Khatoon
- Institute of Organic ChemistryJohannes Kepler University LinzAltenbergerstrasse 694040LinzAustria
| | - Matthias Bechmann
- Institute of Organic ChemistryJohannes Kepler University LinzAltenbergerstrasse 694040LinzAustria
| | - Mario Waser
- Institute of Organic ChemistryJohannes Kepler University LinzAltenbergerstrasse 694040LinzAustria
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7
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Maret C, David N, Pierrot D, Léonel E, Levacher V, Brière JF, Oudeyer S. Synthesis of α-Chloroarylacetic Acid via Electrochemical Carboxylation of α,α-Dichloroarylmethane Derivatives. Molecules 2023; 28:6704. [PMID: 37764480 PMCID: PMC10537669 DOI: 10.3390/molecules28186704] [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: 08/31/2023] [Revised: 09/12/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023] Open
Abstract
The electrocarboxylation of α,α-dichloroarylmethane derivatives in the presence of CO2 was achieved, providing several α-chloroarylacetic acid derivatives with modest yields but high selectivity (chlorinated vs. non-chlorinated or dicarboxylic acid products). The obtained products were then involved in several chemical transformations, underlining their potential as versatile intermediates in synthetic chemistry. A mechanism was also proposed based upon a control experiment and cyclic voltammetry (CV) study.
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Affiliation(s)
- Corentin Maret
- Univ Rouen Normandie, INSA Rouen Normandie, CNRS, Normandie Univ, COBRA UMR 6014, INC3M FR 3038, F-76000 Rouen, France; (C.M.); (N.D.); (D.P.); (V.L.); (J.-F.B.)
| | - Nicolas David
- Univ Rouen Normandie, INSA Rouen Normandie, CNRS, Normandie Univ, COBRA UMR 6014, INC3M FR 3038, F-76000 Rouen, France; (C.M.); (N.D.); (D.P.); (V.L.); (J.-F.B.)
| | - David Pierrot
- Univ Rouen Normandie, INSA Rouen Normandie, CNRS, Normandie Univ, COBRA UMR 6014, INC3M FR 3038, F-76000 Rouen, France; (C.M.); (N.D.); (D.P.); (V.L.); (J.-F.B.)
| | - Eric Léonel
- Université Paris-Est Créteil, ICMPE (UMR 7182), CNRS, UPEC, F-94320 Thiais, France;
| | - Vincent Levacher
- Univ Rouen Normandie, INSA Rouen Normandie, CNRS, Normandie Univ, COBRA UMR 6014, INC3M FR 3038, F-76000 Rouen, France; (C.M.); (N.D.); (D.P.); (V.L.); (J.-F.B.)
| | - Jean-François Brière
- Univ Rouen Normandie, INSA Rouen Normandie, CNRS, Normandie Univ, COBRA UMR 6014, INC3M FR 3038, F-76000 Rouen, France; (C.M.); (N.D.); (D.P.); (V.L.); (J.-F.B.)
| | - Sylvain Oudeyer
- Univ Rouen Normandie, INSA Rouen Normandie, CNRS, Normandie Univ, COBRA UMR 6014, INC3M FR 3038, F-76000 Rouen, France; (C.M.); (N.D.); (D.P.); (V.L.); (J.-F.B.)
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8
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Nimmo AJ, Bitai J, Young CM, McLaughlin C, Slawin AMZ, Cordes DB, Smith AD. Enantioselective isothiourea-catalysed reversible Michael addition of aryl esters to 2-benzylidene malononitriles. Chem Sci 2023; 14:7537-7544. [PMID: 37449062 PMCID: PMC10337745 DOI: 10.1039/d3sc02101g] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 05/31/2023] [Indexed: 07/18/2023] Open
Abstract
Catalytic enantioselective transformations usually rely upon optimal enantioselectivity being observed in kinetically controlled reaction processes, with energy differences between diastereoisomeric transition state energies translating to stereoisomeric product ratios. Herein, stereoselectivity resulting from an unusual reversible Michael addition of an aryl ester to 2-benzylidene malononitrile electrophiles using an isothiourea as a Lewis base catalyst is demonstrated. Notably, the basicity of the aryloxide component and reactivity of the isothiourea Lewis base both affect the observed product selectivity, with control studies and crossover experiments indicating the feasibility of a constructive reversible Michael addition from the desired product. When this reversible addition is coupled with a crystallisation-induced diastereomer transformation (CIDT) it allows isolation of products in high yield and stereocontrol (14 examples, up to 95 : 5 dr and 99 : 1 er). Application of this process to gram scale, plus derivatisations to provide further useful products, is demonstrated.
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Affiliation(s)
- Alastair J Nimmo
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Jacqueline Bitai
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Claire M Young
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Calum McLaughlin
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Alexandra M Z Slawin
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - David B Cordes
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Andrew D Smith
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
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9
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Stockhammer L, Craik R, Monkowius U, Cordes DB, Smith AD, Waser M. Isothiourea-Catalyzed Enantioselective Functionalisation of Glycine Schiff Base Aryl Esters via 1,6- and 1,4-Additions. CHEMISTRYEUROPE 2023; 1:e202300015. [PMID: 38882579 PMCID: PMC7616101 DOI: 10.1002/ceur.202300015] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Indexed: 06/18/2024]
Abstract
The enantioselective α-functionalisation of glycine Schiff base aryl esters through isothiourea catalysis is successfully demonstrated for 1,6-additions to para-quinone methides (21 examples, up to 95:5 dr and 96:4 er) and 1,4-additions to methylene substituted dicarbonyl or disulfonyl Michael acceptors (17 examples, up to 98:2 er). This nucleophilic organocatalysis approach gives access to a range of α-functionalised α-amino acid derivatives and further transformations of the activated aryl ester group provide a straightforward entry to advanced amino acid-based esters, amides or thioesters.
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Affiliation(s)
- Lotte Stockhammer
- Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz (Austria)
| | - Rebecca Craik
- EaStCHEM, School of Chemistry, University of St Andrews, KY16 9ST St Andrews, Fife, (UK)
| | - Uwe Monkowius
- School of Education, Chemistry, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz (Austria)
| | - David B Cordes
- EaStCHEM, School of Chemistry, University of St Andrews, KY16 9ST St Andrews, Fife, (UK)
| | - Andrew D Smith
- EaStCHEM, School of Chemistry, University of St Andrews, KY16 9ST St Andrews, Fife, (UK)
| | - Mario Waser
- Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz (Austria)
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10
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Weinzierl D, Piringer M, Zebrowski P, Stockhammer L, Waser M. Photochemical Wolff Rearrangement Initiated Generation and Subsequent α-Chlorination of C1 Ammonium Enolates. Org Lett 2023; 25:3126-3130. [PMID: 37098273 PMCID: PMC10167681 DOI: 10.1021/acs.orglett.3c00986] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Indexed: 04/27/2023]
Abstract
The enantioselective synthesis of α-chlorinated carboxylic acid esters with er up to 99:1 and yields up to 82% was achieved via a one-pot multistep protocol starting from α-diazoketones. This process proceeds via a photochemical Wolff rearrangement, trapping of the generated ketene with a chiral Lewis base catalyst, subsequent enantioselective α-chlorination, and a final nucleophilic displacement of the bound catalyst. The obtained products were successfully utilized for stereospecific nucleophilic displacement reactions with N- and S-nucleophiles.
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Affiliation(s)
- David Weinzierl
- Institute
of Organic Chemistry, Johannes Kepler University
Linz, Altenbergerstr. 69, 4040 Linz, Austria
| | - Magdalena Piringer
- Institute
of Organic Chemistry, Johannes Kepler University
Linz, Altenbergerstr. 69, 4040 Linz, Austria
| | - Paul Zebrowski
- Institute
of Organic Chemistry, Johannes Kepler University
Linz, Altenbergerstr. 69, 4040 Linz, Austria
| | - Lotte Stockhammer
- Institute
of Organic Chemistry, Johannes Kepler University
Linz, Altenbergerstr. 69, 4040 Linz, Austria
| | - Mario Waser
- Institute
of Organic Chemistry, Johannes Kepler University
Linz, Altenbergerstr. 69, 4040 Linz, Austria
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11
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Cromwell S, Sutio R, Zhang C, Such GK, Lupton DW. Lewis Base Catalyzed Synthesis of Sulfur Heterocycles via the C1‐Pyridinium Enolate. Angew Chem Int Ed Engl 2022; 61:e202206647. [PMID: 35718884 PMCID: PMC9545057 DOI: 10.1002/anie.202206647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Indexed: 12/25/2022]
Abstract
While the addition of C1‐Lewis base enolates to carbonyls and related structures are well established, the related addition to thiocarbonyls compounds are unknown. Herein, we report a reaction cascade in which a C1‐pyridinium enolate undergos addition to dithioesters, trithiocarbonates and xanthates. The reaction provides access to a range of dihydrothiophenes and dihydrothiopyrans (28‐examples). Mechanistic investigations, including isolation of intermediates, electronic correlation, and kinetic isotope effect studies support the viability of an activated acid intermediate giving rise to the C1‐pyridinium enolate which undergoes turnover limiting cyclization. Subsequent formation of a β‐thiolactone regenerates the catalyst with loss of carbon oxysulfide providing the observed products.
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Affiliation(s)
- Simon Cromwell
- School of Chemistry Monash University Clayton 3800, Victoria Australia
| | - Randy Sutio
- School of Chemistry Monash University Clayton 3800, Victoria Australia
| | - Changhe Zhang
- School of Chemistry University of Melbourne Parkville Victoria Australia
| | - Georgina K. Such
- School of Chemistry University of Melbourne Parkville Victoria Australia
| | - David W. Lupton
- School of Chemistry Monash University Clayton 3800, Victoria Australia
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12
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Cromwell S, Sutio R, Zhang C, Such GK, Lupton DW. Lewis Base Catalyzed Synthesis of Sulfur Heterocycles via the C1‐Pyridinium Enolate.**. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202206647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Randy Sutio
- Monash University School of Chemistry AUSTRALIA
| | - Changhe Zhang
- University of Melbourne School of Chemistry School of Chemistry AUSTRALIA
| | - Georgina K. Such
- University of Melbourne School of Chemistry School of Chemistry AUSTRALIA
| | - David W Lupton
- Monash University School of Chemistry Science RoadClayton 3800 Melbourne AUSTRALIA
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13
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Nishimura K, Wang Y, Ogura Y, Kumagai J, Ishihara K. A π–Cu(II)−π Complex as an Extremely Active Catalyst for Enantioselective α-Halogenation of N-Acyl-3,5-dimethylpyrazoles. ACS Catal 2022. [DOI: 10.1021/acscatal.1c05500] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Kazuki Nishimura
- Graduate School of Engineering, Nagoya University, Furo-cho, Nagoya 464-8603, Japan
| | - Yanzhao Wang
- Graduate School of Engineering, Nagoya University, Furo-cho, Nagoya 464-8603, Japan
| | - Yoshihiro Ogura
- Graduate School of Engineering, Nagoya University, Furo-cho, Nagoya 464-8603, Japan
| | - Jun Kumagai
- Graduate School of Engineering, Nagoya University, Furo-cho, Nagoya 464-8603, Japan
| | - Kazuaki Ishihara
- Graduate School of Engineering, Nagoya University, Furo-cho, Nagoya 464-8603, Japan
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14
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Arokianathar JN, Hartley WC, McLaughlin C, Greenhalgh MD, Stead D, Ng S, Slawin AMZ, Smith AD. Isothiourea-Catalyzed Enantioselective α-Alkylation of Esters via 1,6-Conjugate Addition to para-Quinone Methides. Molecules 2021; 26:6333. [PMID: 34770741 PMCID: PMC8588318 DOI: 10.3390/molecules26216333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/12/2021] [Accepted: 10/14/2021] [Indexed: 01/21/2023] Open
Abstract
The isothiourea-catalyzed enantioselective 1,6-conjugate addition of para-nitrophenyl esters to 2,6-disubstituted para-quinone methides is reported. para-Nitrophenoxide, generated in situ from initial N-acylation of the isothiourea by the para-nitrophenyl ester, is proposed to facilitate catalyst turnover in this transformation. A range of para-nitrophenyl ester products can be isolated, or derivatized in situ by addition of benzylamine to give amides at up to 99% yield. Although low diastereocontrol is observed, the diastereoisomeric ester products are separable and formed with high enantiocontrol (up to 94:6 er).
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Affiliation(s)
- Jude N. Arokianathar
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK; (J.N.A.); (W.C.H.); (C.M.); (M.D.G.); (A.M.Z.S.)
| | - Will C. Hartley
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK; (J.N.A.); (W.C.H.); (C.M.); (M.D.G.); (A.M.Z.S.)
| | - Calum McLaughlin
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK; (J.N.A.); (W.C.H.); (C.M.); (M.D.G.); (A.M.Z.S.)
| | - Mark D. Greenhalgh
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK; (J.N.A.); (W.C.H.); (C.M.); (M.D.G.); (A.M.Z.S.)
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
| | - Darren Stead
- AstraZeneca, Oncology R&D, Research & Early Development, Darwin Building, 310, Cambridge Science Park, Milton Road, Cambridge CB4 0WG, UK;
| | - Sean Ng
- Syngenta, Jealott’s Hill International Research Centre, Bracknell RG42 6EY, UK;
| | - Alexandra M. Z. Slawin
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK; (J.N.A.); (W.C.H.); (C.M.); (M.D.G.); (A.M.Z.S.)
| | - Andrew D. Smith
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK; (J.N.A.); (W.C.H.); (C.M.); (M.D.G.); (A.M.Z.S.)
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