1
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Zhu H, Manchado A, Omar Farah A, McKay AP, Cordes DB, Cheong PHY, Kasten K, Smith AD. Isothiourea-Catalysed Acylative Dynamic Kinetic Resolution of Tetra-substituted Morpholinone and Benzoxazinone Lactols. Angew Chem Int Ed Engl 2024; 63:e202402908. [PMID: 38713293 DOI: 10.1002/anie.202402908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/03/2024] [Accepted: 05/06/2024] [Indexed: 05/08/2024]
Abstract
The development of methods to allow the selective acylative dynamic kinetic resolution (DKR) of tetra-substituted lactols is a recognised synthetic challenge. In this manuscript, a highly enantioselective isothiourea-catalysed acylative DKR of tetra-substituted morpholinone and benzoxazinone-derived lactols is reported. The scope and limitations of this methodology have been developed, with high enantioselectivity and good to excellent yields (up to 89 %, 99 : 1 er) observed across a broad range of substrate derivatives incorporating substitution at N(4) and C(2), di- and spirocyclic substitution at C(5) and C(6), as well as benzannulation (>35 examples in total). The DKR process is amenable to scale-up on a 1 g laboratory scale. The factors leading to high selectivity in this DKR process have been probed through computation, with an N-C=O⋅⋅⋅isothiouronium interaction identified as key to producing ester products in highly enantioenriched form.
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Affiliation(s)
- Haoxiang Zhu
- EaStCHEM, School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - Alejandro Manchado
- EaStCHEM, School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
- Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad de Salamanca, Plaza de los Caídos 1-5, 37008, Salamanca, Spain
| | - Abdikani Omar Farah
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331, USA
| | - Aidan P McKay
- 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
| | - Paul Ha-Yeon Cheong
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331, USA
| | - Kevin Kasten
- 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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2
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Agrawal SK, Majhi PK, Goodfellow AS, Tak RK, Cordes DB, McKay AP, Kasten K, Bühl M, Smith AD. Synthesis of Tetra-Substituted 3-Hydroxyphthalide Esters by Isothiourea-Catalysed Acylative Dynamic Kinetic Resolution. Angew Chem Int Ed Engl 2024; 63:e202402909. [PMID: 38713305 DOI: 10.1002/anie.202402909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/03/2024] [Accepted: 05/06/2024] [Indexed: 05/08/2024]
Abstract
A general and highly enantioselective method for the preparation of tetra-substituted 3-hydroxyphthalide esters via isothiourea-catalysed acylative dynamic kinetic resolution (DKR) is reported. Using (2S,3R)-HyperBTM (5 mol %) as the catalyst, the scope and limitations of this methodology have been extensively probed, with high enantioselectivity and good to excellent yields observed (>40 examples, up to 99 %, 99 : 1 er). Substitution of the aromatic core within the 3-hydroxyphthalide skeleton, as well as aliphatic and aromatic substitution at C(3), is readily tolerated. A diverse range of anhydrides, including those from bioactive and pharmaceutically relevant acids, can also be used. The high enantioselectivity observed in this DKR process has been probed computationally, with a key substrate heteroatom donor O⋅⋅⋅acyl-isothiouronium interaction identified through DFT analysis as necessary for enantiodiscrimination.
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Affiliation(s)
- Shubham K Agrawal
- EaStCHEM, School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - Pankaj K Majhi
- EaStCHEM, School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - Alister S Goodfellow
- EaStCHEM, School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - Raj K Tak
- 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
| | - Aidan P McKay
- EaStCHEM, School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - Kevin Kasten
- EaStCHEM, School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - Michael Bühl
- 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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3
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Lin Z, Yu Y, Liu R, Zi W. Design, Preparation, and Implementation of Axially Chiral Benzotetramisoles as Lewis Base Catalysts for Asymmetric Cycloadditions. Angew Chem Int Ed Engl 2024; 63:e202401181. [PMID: 38725281 DOI: 10.1002/anie.202401181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Indexed: 06/21/2024]
Abstract
Developing novel catalysts with potent activity is of great importance in organocatalysis. In this study, we designed and prepared a new class of benzotetramisole Lewis base catalysts (AxBTM) that have both central and axial chirality. This unique feature of these catalysts results in a three-dimensional microenvironment with multi-layers of chirality. The performance of the developed catalysts was tested in a series of cycloaddition reactions. These included the AxBTM-catalyzed (2+2) cycloaddition between α-fluoro-α-aryl anhydride with imines or oxindoles, and the sequential gold/AxBTM-catalyzed (4+2) cycloaddition of enynamides with pentafluorophenyl esters. The interplay between axial and central chirality had a collaborative effect in regulating the stereochemistry in these cycloadditions, leading to high levels of stereoselectivity that would otherwise be challenging to achieve using conventional BTM catalysts. However, the (2+2) and (4+2) cycloadditions have different predilections for axial and central chirality combinations.
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Affiliation(s)
- Zitong Lin
- State Key Laboratory and Institute of Elemento-Organic Chemistry College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
| | - Ying Yu
- State Key Laboratory and Institute of Elemento-Organic Chemistry College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
| | - Rixin Liu
- State Key Laboratory and Institute of Elemento-Organic Chemistry College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
| | - Weiwei Zi
- State Key Laboratory and Institute of Elemento-Organic Chemistry College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
- Haihe Laboratory of Sustainable Chemical Transformations, Tianjin, 300071, China
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4
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De Oliveira Silva A, Masand SA, Farah AO, Laddusaw J, Urbina K, Rodríguez-Alvarado M, Lalancette RA, Cheong PHY, Brenner-Moyer SE. Organocatalytic Enantioselective [1,2]-Stevens Rearrangement of Azetidinium Salts. J Org Chem 2024; 89:9063-9067. [PMID: 38847523 DOI: 10.1021/acs.joc.4c00534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
The first organocatalyzed enantioselective [1,2]-Stevens rearrangement is reported. 4-Alkylideneproline derivatives are produced in up to 86% yield and in up to 90:10 er, with recrystallization enhancing er up to >99.5:0.5. Product configuration was opposite that predicted by existing stereochemical models for this organocatalyst class, and DFT calculations revealed a novel mode of asymmetric induction. The adaptability of this catalytic strategy for asymmetric [1,2]-Stevens rearrangements of other heterocyclic amines was demonstrated.
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Affiliation(s)
- Ana De Oliveira Silva
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Shruti A Masand
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Abdikani Omar Farah
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Jacqueline Laddusaw
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Kelvin Urbina
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | | | - Roger A Lalancette
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Paul Ha-Yeon Cheong
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Stacey E Brenner-Moyer
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
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5
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Conboy A, Goodfellow AS, Kasten K, Dunne J, Cordes DB, Bühl M, Smith AD. De-epimerizing DyKAT of β-lactones generated by isothiourea-catalysed enantioselective [2 + 2] cycloaddition. Chem Sci 2024; 15:8896-8904. [PMID: 38873072 PMCID: PMC11168096 DOI: 10.1039/d4sc01410c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 04/17/2024] [Indexed: 06/15/2024] Open
Abstract
An enantioselective isothiourea-catalysed [2 + 2] cycloaddition of C(1)-ammonium enolates with pyrazol-4,5-diones is used to construct spirocyclic β-lactones in good yields, excellent enantioselectivity (99 : 1 er) but with modest diastereocontrol (typically 70 : 30 dr). Upon ring-opening with morpholine or alternative nucleophilic amines and alcohols β-hydroxyamide and β-hydroxyester products are generated with enhanced diastereocontrol (up to >95 : 5 dr). Control experiments show that stereoconvergence is observed in the ring-opening of diastereoisomeric β-lactones, leading to a single product (>95 : 5 dr, >99 : 1 er). Mechanistic studies and DFT analysis indicate a substrate controlled Dynamic Kinetic Asymmetric Transformation (DyKAT) involving epimerisation at C(3) of the β-lactone under the reaction conditions, coupled with a hydrogen bond-assisted nucleophilic addition to the Si-face of the β-lactone and stereodetermining ring-opening. The scope and limitations of a one-pot protocol consisting of isothiourea-catalysed enantio-determining [2 + 2] cycloaddition followed by diastereo-determining ring-opening are subsequently developed. Variation within the anhydride ammonium enolate precursor, as well as N(1) and C(3) within the pyrazol-4,5-dione scaffold is demonstrated, giving a range of functionalised β-hydroxyamides with high diastereo- and enantiocontrol (>20 examples, up to >95 : 5 dr and >99 : 1 er) via this DyKAT.
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Affiliation(s)
- Aífe Conboy
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Alister S Goodfellow
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Kevin Kasten
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Joanne Dunne
- 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
| | - Michael Bühl
- 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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6
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Zhou Z, Kasten K, Kang T, Cordes DB, Smith AD. Enantioselective Synthesis in Continuous Flow: Polymer-Supported Isothiourea-Catalyzed Enantioselective Michael Addition-Cyclization with α-Azol-2-ylacetophenones. Org Process Res Dev 2024; 28:2041-2049. [PMID: 38783855 PMCID: PMC11110067 DOI: 10.1021/acs.oprd.4c00113] [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: 03/16/2024] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 05/25/2024]
Abstract
A packed reactor bed incorporating a polymer-supported isothiourea HyperBTM catalyst derivative has been used to promote the enantioselective synthesis of a range of heterocyclic products derived from α-azol-2-ylacetophenones and -acetamides combined with alkyl, aryl, and heterocyclic α,β-unsaturated homoanhydrides in continuous flow via an α,β-unsaturated acyl-ammonium intermediate. The products are generated in good to excellent yields and generally in excellent enantiopurity (up to 97:3 er). Scale-up is demonstrated on a 15 mmol scale, giving the heterocyclic product in 68% overall yield with 98:2 er after recrystallization.
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Affiliation(s)
- Zhanyu Zhou
- EaStCHEM, School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, U.K.
| | - Kevin Kasten
- EaStCHEM, School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, U.K.
| | - Tengfei Kang
- EaStCHEM, School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, U.K.
| | - David B. Cordes
- EaStCHEM, School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, U.K.
| | - Andrew D. Smith
- EaStCHEM, School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, U.K.
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7
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Ishihara J. Progress in Lewis-Acid-Templated Diels-Alder Reactions. Molecules 2024; 29:1187. [PMID: 38474699 DOI: 10.3390/molecules29051187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 03/04/2024] [Accepted: 03/05/2024] [Indexed: 03/14/2024] Open
Abstract
The synthesis of natural products with complicated architectures often requires the use of segments with functional groups that can be structurally transformed with the desired stereogenic centers. Bicyclic 𝛾-lactones have great potential as a suitable segment for natural product synthesis. However, the stereoselective construction of such functionalized bicyclic 𝛾-lactones is not as straightforward as one might expect. The template-mediated Diels-Alder reaction is one of the most powerful and versatile methods for providing bicyclic 𝛾-lactones with high regioselectivity and stereoselectivity. In this reaction, the diene is linked to the dienophile by a temporary tether, allowing the reaction to proceed efficiently, yielding a product that can be used for natural product synthesis. This review describes some important instances of the template-mediated Diels-Alder reaction and its application to the synthesis of biologically active compounds.
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Affiliation(s)
- Jun Ishihara
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 853-8521, Japan
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8
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Savin JA, Ávila-Ortíz CG, Leyva-Ramírez MA, Juaristi E. X-ray crystallographic structure of a novel enantiopure chiral isothiourea with potential applications in enantioselective synthesis. Acta Crystallogr C Struct Chem 2024; 80:15-20. [PMID: 38180035 DOI: 10.1107/s2053229623010781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 12/15/2023] [Indexed: 01/06/2024] Open
Abstract
The synthesis of a chiral isothiourea, namely, (4aR,8aR)-3-phenyl-4a,5,6,7,8,8a-hexahydrobenzo[4,5]imidazo[2,1-b]thiazol-9-ium bromide, C15H17N2S+·Br-, with potential organocatalytic and anti-inflammatory activity is reported. The preparation of the heterocycle of interest was carried out in two high-yielding steps. The hydrobromide salt of the isothiourea of interest provided suitable crystals for X-ray diffraction analysis, the results of which are reported. Salient observations from this analysis are the near perpendicular arrangement of the phenyl ring and the mean plane of the heterocycle. This conformational characteristic may be relevant with regard the stereoselectivity induced by the chiral isothiourea in asymmetric reactions. Furthermore, evidence was found for the existence of an S...Br- halogen bond.
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Affiliation(s)
- J Alejandro Savin
- Department of Chemistry, Centro de Investigación y de Estudios Avanzados del IPN, Avenida IPN #2508, Col. San Pedro Zacatenco, 07360 Ciudad de México, Mexico
| | - C Gabriela Ávila-Ortíz
- Department of Chemistry, Centro de Investigación y de Estudios Avanzados del IPN, Avenida IPN #2508, Col. San Pedro Zacatenco, 07360 Ciudad de México, Mexico
| | - Marco Antonio Leyva-Ramírez
- Department of Chemistry, Centro de Investigación y de Estudios Avanzados del IPN, Avenida IPN #2508, Col. San Pedro Zacatenco, 07360 Ciudad de México, Mexico
| | - Eusebio Juaristi
- Department of Chemistry, Centro de Investigación y de Estudios Avanzados del IPN, Avenida IPN #2508, Col. San Pedro Zacatenco, 07360 Ciudad de México, Mexico
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9
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Yuan D, Goodfellow AS, Kasten K, Duan Z, Kang T, Cordes DB, McKay AP, Bühl M, Boyce GR, Smith AD. Understanding divergent substrate stereoselectivity in the isothiourea-catalysed conjugate addition of cyclic α-substituted β-ketoesters to α,β-unsaturated aryl esters. Chem Sci 2023; 14:14146-14156. [PMID: 38098722 PMCID: PMC10717594 DOI: 10.1039/d3sc05470e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 11/20/2023] [Indexed: 12/17/2023] Open
Abstract
The development of enantioselective synthetic methods capable of generating vicinal stereogenic centres, where one is tetrasubstituted (such as either an all-carbon quaternary centre or where one or more substituents are heteroatoms), is a recognised synthetic challenge. Herein, the enantioselective conjugate addition of a range of carbo- and heterocyclic α-substituted β-ketoesters to α,β-unsaturated aryl esters using the isothiourea HyperBTM as a Lewis base catalyst is demonstrated. Notably, divergent diastereoselectivity is observed through the use of either cyclopentanone-derived or indanone-derived substituted β-ketoesters with both generating the desired stereodefined products with high selectivity (>95 : 5 dr, up to 99 : 1 er). The scope and limitations of these processes are demonstrated, alongside application on gram scale. The origin of the divergent substrate selectivity has been probed through the use of DFT-analysis, with preferential orientation driven by dual stabilising CH⋯O interactions. The importance of solvation with strongly polar transition-states is highlighted and the SMD solvation model is demonstrated to capture solvation effects reliably.
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Affiliation(s)
- Ding Yuan
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
- School of Biological and Chemical Engineering, Panzhihua University Panzhihua 617000 China
| | - Alister S Goodfellow
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Kevin Kasten
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Zhuan Duan
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Tengfei Kang
- 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
| | - Aidan P McKay
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Michael Bühl
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Gregory R Boyce
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
- Department of Chemistry and Physics, Florida Gulf Coast University Fort Myers Florida 33965 USA
- Department of Chemistry and Biochemistry, East Stroudsburg University East Stroudsburg Pennsylvania 18301 USA
| | - Andrew D Smith
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
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10
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Saha J, Banerjee S, Malo S, Das AK, Das I. Thermally Activated Geometrical Regioselective E→Z Isomerization-Enabled Cascade Sequences of Conjugated Dienals: Experimental and DFT Studies. Chemistry 2023; 29:e202302335. [PMID: 37555389 DOI: 10.1002/chem.202302335] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/05/2023] [Accepted: 08/09/2023] [Indexed: 08/10/2023]
Abstract
The geometrical regioselective E→Z isomerization of a conjugated alkene under thermal activation pose a challenge due to microscopic reversibility. Herein we report that such reversibility issues can be circumvented by integrating E→Z isomerization with subsequent cyclization cascade, particularly in the absence of commonly employed light, acids, or metal-catalysts. Thus, linearly conjugated dienals in a mixture of toluene-alcohol (2 : 1) solvents or only with alcohol at 60-70 °C can be converted to γ-alkoxybutenolides in moderate to good yields. The intermediary 2Z,4E-isomer can be isolated, which includes the first example of isolating the regioselective isomerization product under thermal conditions. Density functional theory (DFT) studies have been employed to shed light on the feasibility of geometrical alkene isomerization and ensuing cascade sequences. It has been observed that the regioselective 2E,4E→2Z,4E isomerization of dienal is a thermodynamically facile (ΔG <0) process. Structural elucidation further reveals that the presence of a certain charge transfer and a non-covalent interaction may be the primary reasons for the enhanced stability of the 2Z,4E-isomer. The thermodynamic plausibility of the subsequent cascade reaction from the Z-isomer to the anticipated product in the presence of a polar protic solvent (here MeOH) is also explicated. Out of the two probable pathways, the "hemiacetal pathway" involving a relay proton transfer is kinetically more feasible due to the diminished activation barrier than the "conjugate addition pathway".
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Affiliation(s)
- Jayanta Saha
- Organic and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata, 700032, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Soumadip Banerjee
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Sidhartha Malo
- Organic and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata, 700032, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Abhijit Kumar Das
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Indrajit Das
- Organic and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata, 700032, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
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11
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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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12
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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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13
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Wang Y, Young CM, Cordes DB, Slawin AMZ, Smith AD. Probing Regio- and Enantioselectivity in the Formal [2 + 2] Cycloaddition of C(1)-Alkyl Ammonium Enolates with β- and α,β-Substituted Trifluoromethylenones. J Org Chem 2023. [PMID: 37184337 DOI: 10.1021/acs.joc.2c02688] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The isothiourea-catalyzed regio- and enantioselective formal [2 + 2] cycloaddition of C(1)-alkyl and C(1)-unsubstituted ammonium enolates with β- and α,β-substituted trifluoromethylenones has been developed. In all cases, preferential [2 + 2]-cycloaddition over the alternative [4 + 2]-cycloaddition is observed, giving β-lactones with excellent diastereo- and enantioselectivity (34 examples, up to >95:5 dr, >99:1 er). The regioselectivity of the process was dictated by the nature of the substituents on both reaction components. Solely [2 + 2] cycloaddition products are observed when using α,β-substituted trifluoromethylenones or α-trialkylsilyl acetic acid derivatives; both [2 + 2] and [4 + 2] cycloaddition products are observed when using β-substituted trifluoromethylenones and α-alkyl-α-trialkylsilyl acetic acids as reactants, with the [2 + 2] cycloaddition as the major reaction product. The beneficial role of the α-silyl substituent within the acid component in this protocol has been demonstrated by control experiments.
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Affiliation(s)
- Yihong Wang
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, U.K
| | - Claire M Young
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, U.K
| | - David B Cordes
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, U.K
| | - Alexandra M Z Slawin
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, U.K
| | - Andrew D Smith
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, U.K
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14
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Truax NJ, Ayinde S, Liu JO, Romo D. Total Synthesis of Rameswaralide Utilizing a Pharmacophore-Directed Retrosynthetic Strategy. J Am Chem Soc 2022; 144:18575-18585. [PMID: 36166374 DOI: 10.1021/jacs.2c08245] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A pharmacophore-directed retrosynthetic strategy was applied to the first total synthesis of the cembranoid rameswaralide in order to simultaneously achieve a total synthesis while also developing a structure-activity relationship profile throughout the synthetic effort. The synthesis utilized a Diels-Alder lactonization process, including a rare kinetic resolution to demonstrate the potential of this strategy for an enantioselective synthesis providing both the 5,5,6- and, through a ring expansion, 5,5,7-tricyclic ring systems present in several Sinularia soft coral cembranoids. A pivotal synthetic intermediate, a tricyclic epoxy α-bromo cycloheptenone, displayed high cytotoxicity with interesting selectivity toward the HCT-116 colon cancer cell line. This intermediate enabled the pursuit of three unique D-ring annulation strategies including a photocatalyzed intramolecular Giese-type radical cyclization and a diastereoselective, intramolecular enamine-mediated Michael addition, with the latter annulation constructing the final D-ring to deliver rameswaralide. The serendipitous discovery of an oxidation state transposition of the tricyclic epoxy cycloheptenone proceeding through a presumed doubly vinylogous, E1-type elimination enabled the facile introduction of the required α-methylene butyrolactone. Preliminary biological tests of rameswaralide and precursors demonstrated weak cytotoxicity; however, the comparable cytotoxicity of a simple 6,7-bicyclic β-keto ester, corresponding to the CD-ring system of rameswaralide, to that of the natural product itself suggests that such bicyclic β-ketoesters may constitute an interesting pharmacophore that warrants further exploration.
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Affiliation(s)
- Nathanyal J Truax
- Department of Chemistry & Biochemistry, Baylor University, 101 Bagby Avenue, Waco, Texas 76710, United States
| | - Safiat Ayinde
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Jun O Liu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Daniel Romo
- Department of Chemistry & Biochemistry, Baylor University, 101 Bagby Avenue, Waco, Texas 76710, United States
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15
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Wang Y, Young CM, Liu H, Hartley WC, Wienhold M, Cordes DB, Slawin AMZ, Smith AD. A Desilylative Approach to Alkyl Substituted C(1)‐Ammonium Enolates: Application in Enantioselective [2+2] Cycloadditions. Angew Chem Int Ed Engl 2022; 61:e202208800. [PMID: 35833471 PMCID: PMC9543305 DOI: 10.1002/anie.202208800] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Indexed: 11/22/2022]
Abstract
The catalytic generation of C(1)‐ammonium enolates from the corresponding α‐silyl‐α‐alkyl substituted carboxylic acids using the isothiourea HyperBTM is reported. This desilylative approach grants access to α‐unsubstituted and α‐alkyl substituted C(1)‐ammonium enolates, which are typically difficult to access through traditional methods reliant upon deprotonation. The scope and limitations of this process is established in enantioselective [2+2]‐cycloaddition processes with perfluoroalkylketones (31 examples, up to 96 % yield and >99 : 1 er), as well as selective [2+2]‐cycloaddition with trifluoromethyl enones (4 examples, up to 75 % yield and >99 : 1 er). Preliminary mechanistic studies indicate this process proceeds through an initial kinetic resolution of an in situ prepared (±)‐α‐silyl‐α‐alkyl substituted anhydride, while the reaction process exhibits overall pseudo zero‐order kinetics.
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Affiliation(s)
- Yihong Wang
- 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
| | - Honglei Liu
- EaStCHEM School of Chemistry University of St Andrews St Andrews Fife KY16 9ST UK
| | - Will C. Hartley
- EaStCHEM School of Chemistry University of St Andrews St Andrews Fife KY16 9ST UK
| | - Max Wienhold
- 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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16
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Abdelhamid Y, Kasten K, Dunne J, Hartley WC, Young CM, Cordes DB, Slawin AMZ, Ng S, Smith AD. Isothiourea-Catalyzed [2 + 2] Cycloaddition of C(1)-Ammonium Enolates and N-Alkyl Isatins. Org Lett 2022; 24:5444-5449. [PMID: 35848722 PMCID: PMC9490795 DOI: 10.1021/acs.orglett.2c02170] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Enantioselective [2 + 2] cycloaddition of C(1)-ammonium
enolates
generated catalytically using the isothiourea HyperBTM with N-alkyl isatins gives spirocyclic β-lactones. In situ ring opening with an amine nucleophile generates
isolable highly enantioenriched products in up to 92:8 dr and in >99:1
er.
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Affiliation(s)
- Yusra Abdelhamid
- EaStCHEM, School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, U.K., KY16 9ST
| | - Kevin Kasten
- EaStCHEM, School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, U.K., KY16 9ST
| | - Joanne Dunne
- EaStCHEM, School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, U.K., KY16 9ST
| | - Will C Hartley
- EaStCHEM, School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, U.K., KY16 9ST
| | - Claire M Young
- EaStCHEM, School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, U.K., KY16 9ST
| | - David B Cordes
- EaStCHEM, School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, U.K., KY16 9ST
| | - Alexandra M Z Slawin
- EaStCHEM, School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, U.K., KY16 9ST
| | - Sean Ng
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, U.K
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17
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Smith AD, Wang Y, Young CM, Liu H, Hartley WC, Wienhold M, Cordes DB, Slawin AMZ. A Desilylative Approach to Alkyl Substituted C(1)‐Ammonium Enolates: Application in Enantioselective [2+2] Cycloadditions. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202208800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Andrew David Smith
- University of St Andrews School of Chemistry North Haugh FIFE, KY10 3TH St. Andrews UNITED KINGDOM
| | - Yihong Wang
- University of St Andrews School of Chemistry UNITED KINGDOM
| | | | - Honglei Liu
- University of St Andrews School of Chemistry UNITED KINGDOM
| | | | - Max Wienhold
- University of St Andrews School of Chemistry UNITED KINGDOM
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18
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Hartley WC, Schiel F, Ermini E, Melchiorre P. Lewis Base‐Catalysed Enantioselective Radical Conjugate Addition for the Synthesis of Enantioenriched Pyrrolidinones. Angew Chem Int Ed Engl 2022; 61:e202204735. [DOI: 10.1002/anie.202204735] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Indexed: 12/15/2022]
Affiliation(s)
- Will C. Hartley
- ICIQ—Institute of Chemical Research of Catalonia the Barcelona Institute of Science and Technology Avenida Països Catalans 16 43007 Tarragona Spain
| | | | - Elena Ermini
- ICIQ—Institute of Chemical Research of Catalonia the Barcelona Institute of Science and Technology Avenida Països Catalans 16 43007 Tarragona Spain
| | - Paolo Melchiorre
- ICREA— Passeig Lluís Companys 23 08010 Barcelona Spain
- ICIQ—Institute of Chemical Research of Catalonia the Barcelona Institute of Science and Technology Avenida Països Catalans 16 43007 Tarragona Spain
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19
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Bitai J, Nimmo AJ, Slawin AMZ, Smith AD. Cooperative Palladium/Isothiourea Catalyzed Enantioselective Formal (3+2) Cycloaddition of Vinylcyclopropanes and α,β-Unsaturated Esters. Angew Chem Int Ed Engl 2022; 61:e202202621. [PMID: 35389553 PMCID: PMC9324207 DOI: 10.1002/anie.202202621] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Indexed: 12/15/2022]
Abstract
A protocol for the enantioselective synthesis of substituted vinylcyclopentanes has been realised using cooperative palladium and isothiourea catalysis. Treatment of vinylcyclopropanes with Pd(PPh3 )4 generates a zwitterionic π-allyl palladium intermediate that intercepts a catalytically generated α,β-unsaturated acyl ammonium species prepared from the corresponding α,β-unsaturated para-nitrophenyl ester and the isothiourea (R)-BTM. Intermolecular formal (3+2) cycloaddition between these reactive intermediates generates functionalised cyclopentanes in generally good yields and excellent diastereo- and enantiocontrol (up to >95 : 5 dr, 97 : 3 er), with the use of LiCl as an additive proving essential for optimal stereocontrol. To the best of our knowledge a dual transition metal/organocatalytic process involving α,β-unsaturated acyl ammonium intermediates has not been demonstrated previously.
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Affiliation(s)
- Jacqueline Bitai
- EaStCHEM, School of ChemistryUniversity of St AndrewsSt Andrews, FifeKY16 9STUK
| | - Alastair J. Nimmo
- EaStCHEM, School of ChemistryUniversity of St AndrewsSt Andrews, FifeKY16 9STUK
| | | | - Andrew D. Smith
- EaStCHEM, School of ChemistryUniversity of St AndrewsSt Andrews, FifeKY16 9STUK
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20
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Lapetaje JE, Young CM, Shu C, Smith AD. Isothiourea-catalyzed formal enantioselective conjugate addition of benzophenone imines to β-fluorinated α,β-unsaturated esters. Chem Commun (Camb) 2022; 58:6886-6889. [PMID: 35635248 DOI: 10.1039/d2cc01936a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The isothiourea-catalyzed formal enantioselective conjugate addition of 2-hydroxybenzophenone imine derivatives to α,β-unsaturated para-nitrophenyl esters has been developed. Investigations of the scope and limitations of this procedure showed that β-electron withdrawing substituents within the α,β-unsaturated ester component are required for good product yield, giving rise to a range of β-imino ester and amide derivatives in moderate to good isolated yields with excellent enantioselectivity (20 examples, up to 81% yield and 97 : 3 er).
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Affiliation(s)
- Jerson E Lapetaje
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St. Andrews KY16 9ST, UK.
| | - Claire M Young
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St. Andrews KY16 9ST, UK.
| | - Chang Shu
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St. Andrews KY16 9ST, UK.
| | - Andrew D Smith
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St. Andrews KY16 9ST, UK.
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21
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Wu J, Young CM, Watts AA, Slawin AMZ, Boyce GR, Bühl M, Smith AD. Isothiourea-Catalyzed Enantioselective Michael Addition of Malonates to α,β-Unsaturated Aryl Esters. Org Lett 2022; 24:4040-4045. [PMID: 35652512 PMCID: PMC9278409 DOI: 10.1021/acs.orglett.2c01486] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
An enantioselective Michael addition of malonates to α,β-unsaturated para-nitrophenyl esters was achieved using the Lewis basic isothiourea HyperBTM, giving excellent levels of product enantioselectivity (up to >99:1 enantiomeric ratio) in good yields and with complete regioselectivity (>20:1 regioselectivity ratio) in the presence of alternative (phenyl ketone and ethyl ester) Michael acceptors. Density functional theory calculations indicate that N-acylation is rate-limiting. This constitutes a rare example of a highly enantioselective addition of simple, readily available malonates to α,β-unsaturated esters.
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Affiliation(s)
- Jiufeng Wu
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Claire M Young
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Amy A Watts
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Alexandra M Z Slawin
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Gregory R Boyce
- Department of Chemistry and Physics, Florida Gulf Coast University, Fort Myers, Florida 33965, United States
| | - Michael Bühl
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Andrew D Smith
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
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22
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Hartley WC, Schiel F, Ermini E, Melchiorre P. Lewis Base‐Catalysed Enantioselective Radical Conjugate Addition for the Synthesis of Enantioenriched Pyrrolidinones. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202204735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Will C. Hartley
- ICIQ: Institut Catala d'Investigacio Quimica Iciq 43007 Tarragona SPAIN
| | - Florian Schiel
- ICIQ: Institut Catala d'Investigacio Quimica Iciq 43007 Tarragona SPAIN
| | - Elena Ermini
- ICIQ: Institut Catala d'Investigacio Quimica iciq 43007 Tarragona SPAIN
| | - Paolo Melchiorre
- Institute of Chemical Research of Catalonia (ICIQ) ICIQ Av. Països Catalans 16 43007 Tarragona SPAIN
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23
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Kurihara T, Kojima M, Yoshino T, Matsunaga S. Achiral Cp*Rh(III)/Chiral Lewis Base Cooperative Catalysis for Enantioselective Cyclization via C–H Activation. J Am Chem Soc 2022; 144:7058-7065. [DOI: 10.1021/jacs.2c01223] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Takumaru Kurihara
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Masahiro Kojima
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Tatsuhiko Yoshino
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
- Global Station for Biosurfaces and Drug Discovery, Hokkaido University, Kita-12 Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Shigeki Matsunaga
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
- Global Station for Biosurfaces and Drug Discovery, Hokkaido University, Kita-12 Nishi-6, Kita-ku, Sapporo 060-0812, Japan
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24
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Bitai J, Nimmo AJ, Slawin AMZ, Smith AD. Cooperative Palladium/Isothiourea Catalyzed Enantioselective Formal (3+2) Cycloaddition of Vinylcyclopropanes and a,b‐Unsaturated Esters. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | | | | | - Andrew David Smith
- University of St Andrews School of Chemistry North Haugh FIFE, KY10 3TH St. Andrews UNITED KINGDOM
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25
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Nielsen CDT, Linfoot JD, Williams AF, Spivey AC. Recent progress in asymmetric synergistic catalysis - the judicious combination of selected chiral aminocatalysts with achiral metal catalysts. Org Biomol Chem 2022; 20:2764-2778. [PMID: 35298581 PMCID: PMC9082520 DOI: 10.1039/d2ob00025c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In this review we survey recent synergistic applications of a chiral organocatalyst with an achiral metal to perform stereoselective transformations of synthetic utility (since 2016). The transformations are classified by the modes of reactivity deployed, focussing on organocatalytic activation of carbonyl substrates as chiral nucleophiles via the α-position (e.g., as enamines) and as chiral electrophiles via the β-position (e.g., as iminium ions) combined with complementary activation of their reaction partners by an achiral metal co-catalyst (e.g., Pd or Cu-based). Corresponding radical reactions are also presented in which photocatalysis mediated by achiral metal complexes replaces the metal co-catalyst. Certain privileged structures are revealed and opportunities to develop this exciting field are highlighted. A critical survey of recent synergistic applications of a chiral organocatalyst with an achiral metal to perform stereoselective transformations of synthetic utility.![]()
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Affiliation(s)
- Christian D-T Nielsen
- Imperial College London, White City Campus, Molecular Sciences Research Hub (MSRH), 82 Wood Lane, London W12 0BZ, UK.
| | - Joshua D Linfoot
- Imperial College London, White City Campus, Molecular Sciences Research Hub (MSRH), 82 Wood Lane, London W12 0BZ, UK.
| | - Alexander F Williams
- Imperial College London, White City Campus, Molecular Sciences Research Hub (MSRH), 82 Wood Lane, London W12 0BZ, UK.
| | - Alan C Spivey
- Imperial College London, White City Campus, Molecular Sciences Research Hub (MSRH), 82 Wood Lane, London W12 0BZ, UK.
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26
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Smith SM, Greenhalgh MD, Feoktistova T, Walden DM, Taylor JE, Cordes DB, Slawin AMZ, Cheong PH, Smith AD. Scope, Limitations and Mechanistic Analysis of the HyperBTM‐Catalyzed Acylative Kinetic Resolution of Tertiary Heterocyclic Alcohols**. European J Org Chem 2022. [DOI: 10.1002/ejoc.202101111] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Samuel M. Smith
- EaStCHEM School of Chemistry University of St Andrews North Haugh, St Andrews, Fife KY16 9ST UK
| | - Mark D. Greenhalgh
- EaStCHEM School of Chemistry University of St Andrews North Haugh, St Andrews, Fife KY16 9ST UK
- Department of Chemistry University of Warwick Coventry CV4 7AL UK
| | - Taisiia Feoktistova
- Department of Chemistry Oregon State University 153 Gilbert Hall Corvallis OR 97331 USA
| | - Daniel M. Walden
- Department of Chemistry Oregon State University 153 Gilbert Hall Corvallis OR 97331 USA
| | - James E. Taylor
- EaStCHEM School of Chemistry University of St Andrews North Haugh, St Andrews, Fife KY16 9ST UK
- Department of Chemistry University of Bath Claverton Down, Bath BA2 7AY UK
| | - David B. Cordes
- EaStCHEM School of Chemistry University of St Andrews North Haugh, St Andrews, Fife KY16 9ST UK
| | - Alexandra M. Z. Slawin
- EaStCHEM School of Chemistry University of St Andrews North Haugh, St Andrews, Fife KY16 9ST UK
| | - Paul Ha‐Yeon Cheong
- Department of Chemistry Oregon State University 153 Gilbert Hall Corvallis OR 97331 USA
| | - Andrew D. Smith
- EaStCHEM School of Chemistry University of St Andrews North Haugh, St Andrews, Fife KY16 9ST UK
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27
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Davis AE, Lowe JM, Hilinski MK. Vinylazaarenes as dienophiles in Lewis acid-promoted Diels-Alder reactions. Chem Sci 2021; 12:15947-15952. [PMID: 35024118 PMCID: PMC8672738 DOI: 10.1039/d1sc05095h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 11/24/2021] [Indexed: 11/25/2022] Open
Abstract
Described are the first examples of Lewis acid-promoted Diels–Alder reactions of vinylpyridines and other vinylazaarenes with unactivated dienes. Cyclohexyl-appended azaarenes constitute a class of substructures of rising prominence in drug discovery. Despite this, thermal variants of the vinylazaarene Diels–Alder reaction are rare and have not been adopted for synthesis, and Lewis acid-promoted variants are virtually unexplored. The presented work addresses this gap and in the process furnishes increased scope, dramatically higher yields, improved regioselectivity, and high levels of diastereoselectivity compared to prior thermal examples. These reactions provide scalable access to druglike scaffolds not readily available through other methods. More broadly, these studies establish a useful new class of dienophiles that, based on preliminary mechanistic studies, should be amenable to conventional strategies for enantioselective catalysis. Vinyl-substituted azaarenes are rare and challenging substrates as dienophiles in Diels–Alder reactions; by employing Lewis acid activation, high yielding and highly selective cycloadditions with unactivated dienes are enabled.![]()
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Affiliation(s)
- Anna E Davis
- Department of Chemistry, University of Virginia Charlottesville Virginia 22904-4319 USA
| | - Jared M Lowe
- Department of Chemistry, University of Virginia Charlottesville Virginia 22904-4319 USA
| | - Michael K Hilinski
- Department of Chemistry, University of Virginia Charlottesville Virginia 22904-4319 USA
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28
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Desrues T, Merad J, Andrei D, Pons J, Parrain J, Médebielle M, Quintard A, Bressy C. Impact of the Difluoromethylene Group in the Organocatalyzed Acylative Kinetic Resolution of α,α‐Difluorohydrins. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Titouan Desrues
- Aix-Marseille Univ CNRS Centrale Marseille, iSm2 Marseille France
| | - Jérémy Merad
- Univ Lyon Université Lyon 1 CNRS INSA CPE-Lyon ICBMS UMR 5246 Bât. Lederer 1 rue Victor Grignard 69622 Villeurbanne France
| | - Daniela Andrei
- Univ Lyon Université Lyon 1 CNRS INSA CPE-Lyon ICBMS UMR 5246 Bât. Lederer 1 rue Victor Grignard 69622 Villeurbanne France
- Dominican University 7900 West Division Street River Forest IL 60305 USA
| | - Jean‐Marc Pons
- Aix-Marseille Univ CNRS Centrale Marseille, iSm2 Marseille France
| | - Jean‐Luc Parrain
- Aix-Marseille Univ CNRS Centrale Marseille, iSm2 Marseille France
| | - Maurice Médebielle
- Univ Lyon Université Lyon 1 CNRS INSA CPE-Lyon ICBMS UMR 5246 Bât. Lederer 1 rue Victor Grignard 69622 Villeurbanne France
| | - Adrien Quintard
- Aix-Marseille Univ CNRS Centrale Marseille, iSm2 Marseille France
| | - Cyril Bressy
- Aix-Marseille Univ CNRS Centrale Marseille, iSm2 Marseille France
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29
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Desrues T, Merad J, Andrei D, Pons JM, Parrain JL, Médebielle M, Quintard A, Bressy C. Impact of the Difluoromethylene Group in the Organocatalyzed Acylative Kinetic Resolution of α,α-Difluorohydrins. Angew Chem Int Ed Engl 2021; 60:24924-24929. [PMID: 34473886 DOI: 10.1002/anie.202107041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Indexed: 12/15/2022]
Abstract
Due to the omnipresence of chiral organofluorine compounds in pharmaceutical, agrochemical, and material chemistry, the development of enantioselective methods for their preparation is highly desirable. In the present study, the enantioselective organocatalyzed acylation of α,α-difluorohydrins using a commercially available chiral isothiourea is reported through a kinetic resolution (KR) process. It reveals that the difluoromethylene moiety (C(sp3 )F2 ) can serve as a directing group through electrostatic fluorine-cation interactions, greatly improving the enantioselectivity of the KR. In this context, a broad range of fluorinated alcohols such as valuable 4,4-difluoro-1,3-diols could be synthesized with exquisite enantiocontrol (typically >99:1 er). Turning to 2,2-difluoro-1,3-diols, we also demonstrated that aromatic and fluorinated groups were mutually compatible to provide the expected enantioenriched adducts with >99:1 er.
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Affiliation(s)
- Titouan Desrues
- Aix-Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France
| | - Jérémy Merad
- Univ Lyon, Université Lyon 1, CNRS, INSA, CPE-Lyon, ICBMS, UMR 5246, Bât. Lederer, 1 rue Victor Grignard, 69622, Villeurbanne, France
| | - Daniela Andrei
- Univ Lyon, Université Lyon 1, CNRS, INSA, CPE-Lyon, ICBMS, UMR 5246, Bât. Lederer, 1 rue Victor Grignard, 69622, Villeurbanne, France.,Dominican University, 7900 West Division Street, River Forest, IL, 60305, USA
| | - Jean-Marc Pons
- Aix-Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France
| | - Jean-Luc Parrain
- Aix-Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France
| | - Maurice Médebielle
- Univ Lyon, Université Lyon 1, CNRS, INSA, CPE-Lyon, ICBMS, UMR 5246, Bât. Lederer, 1 rue Victor Grignard, 69622, Villeurbanne, France
| | - Adrien Quintard
- Aix-Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France
| | - Cyril Bressy
- Aix-Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France
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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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31
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McLaughlin C, Bitai J, Barber LJ, Slawin AMZ, Smith AD. Catalytic enantioselective synthesis of 1,4-dihydropyridines via the addition of C(1)-ammonium enolates to pyridinium salts. Chem Sci 2021; 12:12001-12011. [PMID: 34667566 PMCID: PMC8457386 DOI: 10.1039/d1sc03860e] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 08/05/2021] [Indexed: 12/30/2022] Open
Abstract
The regio- and stereoselective addition of C(1)-ammonium enolates - generated in situ from aryl esters and the isothiourea catalyst (R)-BTM - to pyridinium salts bearing an electron withdrawing substituent in the 3-position allows the synthesis of a range of enantioenriched 1,4-dihydropyridines. This represents the first organocatalytic approach to pyridine dearomatisation using pronucleophiles at the carboxylic acid oxidation level. Optimisation studies revealed a significant solvent dependency upon product enantioselectivity, with only toluene providing significant asymmetric induction. Using DABCO as a base also proved beneficial for product enantioselectivity, while investigations into the nature of the counterion showed that co-ordinating bromide or chloride substrates led to higher product er than the corresponding tetrafluoroborate or hexafluorophosphate. The scope and limitations of this process are developed, with enantioselective addition to 3-cyano- or 3-sulfonylpyridinium salts giving the corresponding 1,4-dihydropyridines (15 examples, up to 95 : 5 dr and 98 : 2 er).
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Affiliation(s)
- Calum McLaughlin
- 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
| | - Lydia J Barber
- 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
| | - Andrew D Smith
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
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32
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Wang N, Wu Z, Wang J, Ullah N, Lu Y. Recent applications of asymmetric organocatalytic annulation reactions in natural product synthesis. Chem Soc Rev 2021; 50:9766-9793. [PMID: 34286704 DOI: 10.1039/d0cs01124j] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The past two decades have witnessed remarkable growth of asymmetric organocatalysis, which is now a firmly established synthetic tool, serving as a powerful platform for the production of chiral molecules. Ring structures are ubiquitous in organic compounds, and, in the context of natural product synthesis, strategic construction of ring motifs is often crucial, fundamentally impacting the eventual fate of the whole synthetic plan. In this review, we provide a comprehensive and updated summary of asymmetric organocatalytic annulation reactions; in particular, the application of these annulation strategies in natural product synthesis will be highlighted.
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Affiliation(s)
- Nengzhong Wang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore.
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33
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Kiledal SA, Jourdain R, Vellalath S, Romo D. Multicomponent Enantioselective Synthesis of Tetrahydropyridazinones Employing Chiral α,β-Unsaturated Acylammonium Salts. Org Lett 2021; 23:6622-6627. [PMID: 34436913 DOI: 10.1021/acs.orglett.1c02044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An enantioselective three-component reaction was developed for the synthesis of tetrahydropyridazinones employing chiral α,β-unsaturated acylammonium salts, malonates, and azodicarboxylates. An initial α-amination of a malonate with an azodicarboxylate and a subsequent chiral Lewis-base-catalyzed Michael/proton transfer/lactamization process delivered optically active tetrahydropyridazinones (up to 99:1 er). Subsequent transformations of these adducts were explored, revealing some unexpected rearrangements, and the use of an allyl methyl malonate enabled a subsequent deallylative decarboxylation and the introduction of a second stereocenter.
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Affiliation(s)
- Sigrid A Kiledal
- Department of Chemistry & Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Roxane Jourdain
- Department of Chemistry & Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Sreekumar Vellalath
- Department of Chemistry & Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Daniel Romo
- Department of Chemistry & Biochemistry, Baylor University, Waco, Texas 76706, United States
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34
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Zhao F, Shu C, Young CM, Carpenter‐Warren C, Slawin AMZ, Smith AD. Enantioselective Synthesis of α-Aryl-β 2 -Amino-Esters by Cooperative Isothiourea and Brønsted Acid Catalysis. Angew Chem Int Ed Engl 2021; 60:11892-11900. [PMID: 33646631 PMCID: PMC8252622 DOI: 10.1002/anie.202016220] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Indexed: 01/07/2023]
Abstract
The synthesis of α-aryl-β2 -amino esters through enantioselective aminomethylation of an arylacetic acid ester in high yields and enantioselectivity via cooperative isothiourea and Brønsted acid catalysis is demonstrated. The scope and limitations of this process are explored (25 examples, up to 94 % yield and 96:4 er), with applications to the synthesis of (S)-Venlafaxine⋅HCl and (S)-Nakinadine B. Mechanistic studies are consistent with a C(1)-ammonium enolate pathway being followed rather than an alternative dynamic kinetic resolution process. Control studies indicate that (i) a linear effect between catalyst and product er is observed; (ii) an acyl ammonium ion can be used as a precatalyst; (iii) reversible isothiourea addition to an in situ generated iminium ion leads to an off-cycle intermediate that can be used as a productive precatalyst.
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Affiliation(s)
- Feng Zhao
- EaStCHEMSchool of ChemistryUniversity of St AndrewsSt AndrewsFifeKY16 9STUK
| | - Chang Shu
- EaStCHEMSchool of ChemistryUniversity of St AndrewsSt AndrewsFifeKY16 9STUK
| | - Claire M. Young
- EaStCHEMSchool of ChemistryUniversity of St AndrewsSt AndrewsFifeKY16 9STUK
| | | | | | - Andrew D. Smith
- EaStCHEMSchool of ChemistryUniversity of St AndrewsSt AndrewsFifeKY16 9STUK
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35
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Zhao F, Shu C, Young CM, Carpenter‐Warren C, Slawin AMZ, Smith AD. Enantioselective Synthesis of α‐Aryl‐β
2
‐Amino‐Esters by Cooperative Isothiourea and Brønsted Acid Catalysis. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016220] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Feng Zhao
- EaStCHEM School of Chemistry University of St Andrews St Andrews Fife KY16 9ST UK
| | - Chang Shu
- 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
| | | | | | - Andrew D. Smith
- EaStCHEM School of Chemistry University of St Andrews St Andrews Fife KY16 9ST UK
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36
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Bitai J, Westwood MT, Smith AD. α,β-Unsaturated acyl ammonium species as reactive intermediates in organocatalysis: an update. Org Biomol Chem 2021; 19:2366-2384. [PMID: 33650626 DOI: 10.1039/d0ob02208j] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
α,β-Unsaturated acyl ammonium species are versatile intermediates that have been applied in a variety of transformations including Michael additions, domino reactions and cycloadditions. Many of these transformations are promoted by chiral Lewis base catalysts, enabling the rapid generation of molecular complexity with high stereochemical control. This review highlights recent developments in the generation and application of α,β-unsaturated acyl ammonium intermediates reported since a previous review of this area in 2016. Particular emphasis will be placed on reports providing mechanistic insight into catalytic transformations and observed selectivities. A perspective on current challenges and potential future developments in the field of α,β-unsaturated acyl ammonium catalysis is also provided.
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Affiliation(s)
- Jacqueline Bitai
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, Fife, Scotland, KY16 9ST, UK.
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37
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Stereoselective organocascades: from fundamentals to recent developments. PHYSICAL SCIENCES REVIEWS 2021. [DOI: 10.1515/psr-2018-0096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Reaction sequences where more bonds are sequentially formed (cascade reactions) may be started either by a stoichiometric or by a catalytic reagent, and proceed in an enantio- diastereo- or non-stereo- selective manner. A wide variety of such strategies has been developed, including both stoichiometric and catalytic ones.
Within the widely developed cascade reactions field, this chapter is not meant to be omni-comprehensive, but to offer an as much as possible complete overview on organocatalytic stereoselective methods. We embrace the more general definitions by Tietze and Denmark, considering as cascade reactions all those one-pot processes that involve two or more bond formations, where each subsequent step is enabled by a structural change caused by the previous one. We will include both two- and multi-component reactions where one or more organocatalysts may be responsible either for all or just some of the occurring transformations. Organocascades will be reported according to the number of involved catalytic cycles.
In the following paragraphs, only cascade reactions that are stereoselective by means of a chiral catalyst will be considered. It will be shown that multiple possibilities, relying on different catalysis modes, are available to achieve the same reaction sequence.
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38
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Asano K. Multipoint Recognition of Molecular Conformations with Organocatalysts for Asymmetric Synthetic Reactions. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20200343] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Keisuke Asano
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyotodaigaku-Katsura, Nishikyo, Kyoto 615-8510, Japan
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39
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McLaughlin C, Smith AD. Generation and Reactivity of C(1)-Ammonium Enolates by Using Isothiourea Catalysis. Chemistry 2021; 27:1533-1555. [PMID: 32557875 PMCID: PMC7894297 DOI: 10.1002/chem.202002059] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Indexed: 12/17/2022]
Abstract
C(1)-Ammonium enolates are powerful, catalytically generated synthetic intermediates applied in the enantioselective α-functionalisation of carboxylic acid derivatives. This minireview describes the recent developments in the generation and application of C(1)-ammonium enolates from various precursors (carboxylic acids, anhydrides, acyl imidazoles, aryl esters, α-diazoketones, alkyl halides) using isothiourea Lewis base organocatalysts. Their synthetic utility in intra- and intermolecular enantioselective C-C and C-X bond forming processes on reaction with various electrophiles will be showcased utilising two distinct catalyst turnover approaches.
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Affiliation(s)
- Calum McLaughlin
- EaStCHEMSchool of ChemistryUniversity of St AndrewsNorth HaughFifeKY16 9STScotland
| | - Andrew D. Smith
- EaStCHEMSchool of ChemistryUniversity of St AndrewsNorth HaughFifeKY16 9STScotland
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40
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41
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Chaheine CM, Song CJ, Gladen PT, Romo D. Enantioselective Michael-Proton Transfer-Lactamization for Pyroglutamic Acid Derivatives: Synthesis of Dimethyl-( S,E)-5-oxo-3-styryl-1-tosylpyrrolidine-2,2-dicarboxylate. ORGANIC SYNTHESES; AN ANNUAL PUBLICATION OF SATISFACTORY METHODS FOR THE PREPARATION OF ORGANIC CHEMICALS 2021; 98:194-226. [PMID: 36090506 PMCID: PMC9463714 DOI: 10.15227/orgsyn.098.0194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Affiliation(s)
| | - Conner J Song
- Department of Chemistry & Biochemistry, Baylor University, Waco, TX 76710
| | - Paul T Gladen
- Department of Chemistry & Biochemistry, Baylor University, Waco, TX 76710
| | - Daniel Romo
- Department of Chemistry & Biochemistry, Baylor University, Waco, TX 76710
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42
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Varlet T, Masson G. Enamides and dienamides in phosphoric acid-catalysed enantioselective cycloadditions for the synthesis of chiral amines. Chem Commun (Camb) 2021; 57:4089-4105. [DOI: 10.1039/d1cc00590a] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This feature article describes how enamides and dienamides can participate in chiral phosphoric acid catalyzed enantioselective cycloadditions to prepare a wide range of cyclic amines.
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Affiliation(s)
- Thomas Varlet
- Université Paris-Saclay
- Institut de Chimie des Substances Naturelles
- ICSN-CNRS UPR 2301
- 91198 Gif-sur-Yvette
- France
| | - Géraldine Masson
- Université Paris-Saclay
- Institut de Chimie des Substances Naturelles
- ICSN-CNRS UPR 2301
- 91198 Gif-sur-Yvette
- France
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Abstract
Covering: 1986 to 2020Natural products are an enduring source of chemical information useful for probing biologically relevant chemical space. Toward gathering further structure-activity relationship (SAR) information for a particular natural product, synthetic chemists traditionally proceeded first by a total synthesis effort followed by the synthesis of simplified derivatives. While this approach has proven fruitful, it often does not incorporate hypotheses regarding structural features necessary for bioactivity at the synthetic planning stage, but rather focuses on the rapid assembly of the targeted natural product; a goal that often supersedes the opportunity to gather SAR information en route to the natural product. Furthermore, access to simplified variants of a natural product possessing only the proposed essential structural features necessary for bioactivity, typically at lower oxidation states overall, is sometimes non-trivial from the original established synthetic route. In recent years, several synthetic design strategies were described to streamline the process of finding bioactive molecules in concert with fathering further SAR studies for targeted natural products. This review article will briefly discuss traditional retrosynthetic strategies and contrast them to selected examples of recent synthetic strategies for the investigation of biologically relevant chemical space revealed by natural products. These strategies include: diversity-oriented synthesis (DOS), biology-oriented synthesis (BIOS), diverted-total synthesis (DTS), analogue-oriented synthesis (AOS), two-phase synthesis, function-oriented synthesis (FOS), and computed affinity/dynamically ordered retrosynthesis (CANDOR). Finally, a description of pharmacophore-directed retrosynthesis (PDR) developed in our laboratory and initial applications will be presented that was initially inspired by a retrospective analysis of our synthetic route to pateamine A completed in 1998.
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Affiliation(s)
- Nathanyal J Truax
- Department of Chemistry & Biochemistry, Baylor University, Waco, Texas 76710, USA.
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44
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Zhang S, Bacheley L, Young CM, Stark DG, O'Riordan T, Slawin AMZ, Smith AD. Isothiourea‐Catalyzed Functionalization of Pyrrolyl‐ and Indolylacetic Acid: Enantioselective Synthesis of Dihydropyridinones and One‐pot Synthesis of Pyridinones. ASIAN J ORG CHEM 2020. [DOI: 10.1002/ajoc.202000290] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Shuyue Zhang
- EastCHEM School of Chemistry University of St Andrews North Haugh Fife Scotland Scotland KY16 9ST UK
| | - Lucas Bacheley
- EastCHEM School of Chemistry University of St Andrews North Haugh Fife Scotland Scotland KY16 9ST UK
| | - Claire M. Young
- EastCHEM School of Chemistry University of St Andrews North Haugh Fife Scotland Scotland KY16 9ST UK
| | - Daniel G. Stark
- EastCHEM School of Chemistry University of St Andrews North Haugh Fife Scotland Scotland KY16 9ST UK
| | - Timothy O'Riordan
- Syngenta Jealott's Hill International Research Centre Bracknell Berkshire RG42 6EY UK
| | - Alexandra M. Z. Slawin
- EastCHEM School of Chemistry University of St Andrews North Haugh Fife Scotland Scotland KY16 9ST UK
| | - Andrew D. Smith
- EastCHEM School of Chemistry University of St Andrews North Haugh Fife Scotland Scotland KY16 9ST UK
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45
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Biswas A, Mondal H, Maji MS. Synthesis of Heterocycles by isothiourea organocatalysis. J Heterocycl Chem 2020. [DOI: 10.1002/jhet.4119] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Anup Biswas
- Department of Chemistry Hooghly Women's College Hooghly India
| | - Haripriyo Mondal
- Department of Chemistry Indian Institute of Technology Kharagpur India
| | - Modhu S. Maji
- Department of Chemistry Indian Institute of Technology Kharagpur India
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46
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Qu S, Smith SM, Laina‐Martín V, Neyyappadath RM, Greenhalgh MD, Smith AD. Isothiourea-Catalyzed Acylative Kinetic Resolution of Tertiary α-Hydroxy Esters. Angew Chem Int Ed Engl 2020; 59:16572-16578. [PMID: 32491267 PMCID: PMC7540711 DOI: 10.1002/anie.202004354] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/28/2020] [Indexed: 01/08/2023]
Abstract
A highly enantioselective isothiourea-catalyzed acylative kinetic resolution (KR) of acyclic tertiary alcohols has been developed. Selectivity factors of up to 200 were achieved for the KR of tertiary alcohols bearing an adjacent ester substituent, with both reaction conversion and enantioselectivity found to be sensitive to the steric and electronic environment at the stereogenic tertiary carbinol centre. For more sterically congested alcohols, the use of a recently-developed isoselenourea catalyst was optimal, with equivalent enantioselectivity but higher conversion achieved in comparison to the isothiourea HyperBTM. Diastereomeric acylation transition state models are proposed to rationalize the origins of enantiodiscrimination in this process. This KR procedure was also translated to a continuous-flow process using a polymer-supported variant of the catalyst.
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Affiliation(s)
- Shen Qu
- EaStChemSchool of ChemistryUniversity of St AndrewsNorth HaughSt AndrewsFifeKY16 9STUK
| | - Samuel M. Smith
- EaStChemSchool of ChemistryUniversity of St AndrewsNorth HaughSt AndrewsFifeKY16 9STUK
| | - Víctor Laina‐Martín
- EaStChemSchool of ChemistryUniversity of St AndrewsNorth HaughSt AndrewsFifeKY16 9STUK
| | | | - Mark D. Greenhalgh
- EaStChemSchool of ChemistryUniversity of St AndrewsNorth HaughSt AndrewsFifeKY16 9STUK
| | - Andrew D. Smith
- EaStChemSchool of ChemistryUniversity of St AndrewsNorth HaughSt AndrewsFifeKY16 9STUK
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Qu S, Smith SM, Laina‐Martín V, Neyyappadath RM, Greenhalgh MD, Smith AD. Isothiourea‐Catalyzed Acylative Kinetic Resolution of Tertiary α‐Hydroxy Esters. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004354] [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)
- Shen Qu
- EaStChemSchool of ChemistryUniversity of St Andrews North Haugh St Andrews Fife KY16 9ST UK
| | - Samuel M. Smith
- EaStChemSchool of ChemistryUniversity of St Andrews North Haugh St Andrews Fife KY16 9ST UK
| | - Víctor Laina‐Martín
- EaStChemSchool of ChemistryUniversity of St Andrews North Haugh St Andrews Fife KY16 9ST UK
| | | | - Mark D. Greenhalgh
- EaStChemSchool of ChemistryUniversity of St Andrews North Haugh St Andrews Fife KY16 9ST UK
| | - Andrew D. Smith
- EaStChemSchool of ChemistryUniversity of St Andrews North Haugh St Andrews Fife KY16 9ST UK
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48
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Exploring the Scope of Tandem Palladium and Isothiourea Relay Catalysis for the Synthesis of α-Amino Acid Derivatives. Molecules 2020; 25:molecules25102463. [PMID: 32466341 PMCID: PMC7287902 DOI: 10.3390/molecules25102463] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 02/06/2023] Open
Abstract
The scope and limitations of a tandem N-allylation/[2,3]-rearrangement protocol are investigated through the incorporation of a variety of functional groups within an allylic phosphate precursor. This method uses readily accessible N,N-dimethylglycine aryl esters and functionalized allylic phosphates, forming quaternary ammonium salts in situ in the presence of a palladium catalyst. Subsequent enantioselective [2,3]-sigmatropic rearrangement, promoted by the chiral isothiourea tetramisole, generates α-amino acid derivatives with two contiguous stereocenters. The incorporation of electron-withdrawing ester and amide groups gave the best results, furnishing the desired products in moderate to good yields (29–70%), with low diastereocontrol (typically 60:40 dr) but high enantioselectivity (up to 90:10 er). These results indicate that substrate–catalyst interactions in the proposed transition state are sensitive to the substitution pattern of the substrates.
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Zhang YC, Geng RL, Song J, Gong LZ. Isothiourea and Brønsted Acid Cooperative Catalysis: Enantioselective Construction of Dihydropyridinones. Org Lett 2020; 22:2261-2265. [DOI: 10.1021/acs.orglett.0c00461] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Yu-Chen Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Rui-Long Geng
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Jin Song
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Liu-Zhu Gong
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
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50
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Liu H, Slawin AMZ, Smith AD. Isothiourea-Catalyzed Enantioselective Synthesis of Tetrahydro-α-carbolinones. Org Lett 2020; 22:1301-1305. [DOI: 10.1021/acs.orglett.9b04615] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Honglei Liu
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, U.K
| | - Alexandra M. Z. Slawin
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, U.K
| | - Andrew D. Smith
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, U.K
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