1
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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: 3] [Impact Index Per Article: 3.0] [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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2
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Wang H, Zhou Y, Xie Y, Liu Y, Li Y, Zhang H, Long J. Synthesis of functionalized 3-aryl-3 H-benzofuranone derivatives from aryl acetate via [3 + 2] annulation of 1,4-dihydroxy-2-naphthoic acid ester. Org Biomol Chem 2023; 21:1821-1826. [PMID: 36751732 DOI: 10.1039/d2ob02319a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A novel [3 + 2] cascade reaction of aryl acetate with 1,4-dihydroxy-2-naphthoic acid ester by cooperative catalysis of isothiourea and vanadium is developed. The key step of the reaction is that the C1-ammonium enolates generated from aryl acetate will cycloadduct to 1,4-naphthoquinone intermediates. 3-Aryl-3H-benzofuranone derivatives can be prepared in medium to good yields under mild conditions.
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Affiliation(s)
- Huan Wang
- School of Chemistry and Environmental Engineering, Sichuan University of Science & Engineering, 180 Xueyuan Street, Huixing Lu, Zigong, Sichuan, 643000, China.
| | - Yuxiang Zhou
- School of Chemistry and Environmental Engineering, Sichuan University of Science & Engineering, 180 Xueyuan Street, Huixing Lu, Zigong, Sichuan, 643000, China.
| | - Ying Xie
- School of Chemistry and Environmental Engineering, Sichuan University of Science & Engineering, 180 Xueyuan Street, Huixing Lu, Zigong, Sichuan, 643000, China.
| | - Yi Liu
- School of Chemistry and Environmental Engineering, Sichuan University of Science & Engineering, 180 Xueyuan Street, Huixing Lu, Zigong, Sichuan, 643000, China.
| | - Yulong Li
- School of Chemistry and Environmental Engineering, Sichuan University of Science & Engineering, 180 Xueyuan Street, Huixing Lu, Zigong, Sichuan, 643000, China.
| | - Hao Zhang
- College of Vanadium and Titanium, Panzhihua University, 10 Airport Lu, Panzhihua, Sichuan, 617000, China
| | - Jilang Long
- College of Chemistry and Chemical Engineering, China West Normal University, 1 Shida Lu, Nanchong, Sichuan, 637002, China
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3
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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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4
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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: 37] [Impact Index Per Article: 12.3] [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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5
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Zhu CF, Zhang J, Zhu YL, Hao WJ, Tu SJ, Wang DC, Jiang B. A photoinduced arene–alkyne [3 + 2] cycloaddition cascade of 1-alkynylnaphthalen-2-ols for tunable synthesis of skeletally diverse bridged hexacycles. Org Chem Front 2021. [DOI: 10.1039/d1qo00124h] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Photoinduced solvent-dependent cyclodimerizations of 1-alkynylnaphthalen-2-ols were developed for the first time, producing skeletally diverse bridged hexacyclic architectures with good yields and high stereoselectivities.
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Affiliation(s)
- Chi-Fan Zhu
- School of Pharmaceutical Sciences
- Nanjing Tech University
- Nanjing
- P. R. China
- School of Chemistry & Materials Science
| | - Jie Zhang
- School of Chemistry & Materials Science
- Jiangsu Normal University
- Xuzhou
- P. R. China
| | - Yi-Long Zhu
- School of Pharmaceutical Sciences
- Nanjing Tech University
- Nanjing
- P. R. China
| | - Wen-Juan Hao
- School of Chemistry & Materials Science
- Jiangsu Normal University
- Xuzhou
- P. R. China
| | - Shu-Jiang Tu
- School of Chemistry & Materials Science
- Jiangsu Normal University
- Xuzhou
- P. R. China
| | - De-Cai Wang
- School of Pharmaceutical Sciences
- Nanjing Tech University
- Nanjing
- P. R. China
| | - Bo Jiang
- School of Chemistry & Materials Science
- Jiangsu Normal University
- Xuzhou
- P. R. China
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6
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Kuri T, Mizukami Y, Shimogaki M, Fujita M. Oxetane Intermediate during a Direct Aldol Reaction: Stereoselective [5 + 1] Annulation Affording Tetralines. Org Lett 2020; 22:7613-7616. [PMID: 32969668 DOI: 10.1021/acs.orglett.0c02816] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An oxetane intermediate during a direct aldol reaction was trapped with an internal aryl group to yield trans-tetraline products. The contribution of the oxetane intermediate was confirmed by 18O-isotope labeling experiments.
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Affiliation(s)
- Takeshi Kuri
- Graduate School of Material Science, University of Hyogo, Kohto, Kamigori, Hyogo 678-1297, Japan
| | - Yoshihiko Mizukami
- Graduate School of Material Science, University of Hyogo, Kohto, Kamigori, Hyogo 678-1297, Japan
| | - Mio Shimogaki
- Graduate School of Material Science, University of Hyogo, Kohto, Kamigori, Hyogo 678-1297, Japan
| | - Morifumi Fujita
- Graduate School of Material Science, University of Hyogo, Kohto, Kamigori, Hyogo 678-1297, Japan
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7
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Oleksak P, Gonda J, Nepovimova E, Kuca K, Musilek K. The oxazolomycin family: a review of current knowledge. RSC Adv 2020; 10:40745-40794. [PMID: 35519217 PMCID: PMC9057759 DOI: 10.1039/d0ra08396h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 10/25/2020] [Indexed: 12/19/2022] Open
Abstract
Oxazolomycin A and neooxazolomycin were firstly isolated in 1985 by the group of Uemura et al. from the Streptomyces sp. bacteria.
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Affiliation(s)
- Patrik Oleksak
- University of Hradec Kralove
- Faculty of Science
- Department of Chemistry
- Hradec Kralove
- Czech Republic
| | - Jozef Gonda
- Pavol Jozef Safarik University
- Faculty of Science
- Department of Organic Chemistry
- Kosice
- Slovak Republic
| | - Eugenie Nepovimova
- University of Hradec Kralove
- Faculty of Science
- Department of Chemistry
- Hradec Kralove
- Czech Republic
| | - Kamil Kuca
- University of Hradec Kralove
- Faculty of Science
- Department of Chemistry
- Hradec Kralove
- Czech Republic
| | - Kamil Musilek
- University of Hradec Kralove
- Faculty of Science
- Department of Chemistry
- Hradec Kralove
- Czech Republic
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8
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Barrios Antúnez DJ, Greenhalgh MD, Brueckner AC, Walden DM, Elías-Rodríguez P, Roberts P, Young BG, West TH, Slawin AMZ, Ha-Yeon Cheong P, Smith AD. Catalytic enantioselective synthesis of perfluoroalkyl-substituted β-lactones via a concerted asynchronous [2 + 2] cycloaddition: a synthetic and computational study. Chem Sci 2019; 10:6162-6173. [PMID: 31360423 PMCID: PMC6585878 DOI: 10.1039/c9sc00390h] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 04/27/2019] [Indexed: 11/21/2022] Open
Abstract
The enantioselective preparation of a range of perfluoroalkyl-substituted β-lactones through an isothiourea (HyperBTM) catalysed reaction using symmetric anhydrides as ammonium enolate precursors and perfluoroalkylketones (RF = CF3, C2F5, C4F9) is reported. Following optimisation, high diastereo- and enantioselectivity was observed for β-lactone formation using C2F5- and C4F9-substituted ketones at room temperature (26 examples, up to >95 : 5 dr and >99 : 1 er), whilst -78 °C was necessary for optimal dr and er with CF3-substituted ketones (11 examples, up to >95 : 5 dr and >99 : 1 er). Derivatisation of the β-lactones through ring-opening, as well as a two-step conversion to give perfluoroalkyl-substituted oxetanes, is demonstrated without loss of stereochemical integrity. Density functional theory computations, alongside 13C natural abundance KIE studies, have been used to probe the reaction mechanism with a concerted asynchronous [2 + 2]-cycloaddition pathway favoured over a stepwise aldol-lactonisation process.
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Affiliation(s)
| | - Mark D Greenhalgh
- EaStCHEM , School of Chemistry , University of St Andrews , North Haugh , St Andrews , KY16 9ST , UK .
| | - Alexander C Brueckner
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97333 , USA .
| | - Daniel M Walden
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97333 , USA .
| | - Pilar Elías-Rodríguez
- EaStCHEM , School of Chemistry , University of St Andrews , North Haugh , St Andrews , KY16 9ST , UK .
| | - Patrick Roberts
- EaStCHEM , School of Chemistry , University of St Andrews , North Haugh , St Andrews , KY16 9ST , UK .
| | - Benjamin G Young
- Department of Chemistry, Physics, and Engineering , Biola University , 315 Lim Center , La Mirada , California 90639 , USA
| | - Thomas H West
- EaStCHEM , School of Chemistry , University of St Andrews , North Haugh , St Andrews , KY16 9ST , UK .
| | - Alexandra M Z Slawin
- EaStCHEM , School of Chemistry , University of St Andrews , North Haugh , St Andrews , KY16 9ST , UK .
| | - Paul Ha-Yeon Cheong
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97333 , USA .
| | - Andrew D Smith
- EaStCHEM , School of Chemistry , University of St Andrews , North Haugh , St Andrews , KY16 9ST , UK .
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9
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Abstract
Dysoline, a novel chromone alkaloid isolated from Dysoxylum binectariferum, was reported to have selective cytotoxicity for HT1080 fibrosarcoma cells (IC50 of 0.21 μM). Given the scarcity of natural material, a concise synthesis of (+)-dysoline was developed, allowing for further biological evaluation. An enantioselective nucleophile-catalyzed aldol lactonization formed the piperidine ring with control of relative and absolute stereochemistry. Construction of the C6-chromone core with complete regioselectivity was achieved using a Danheiser benzannulation.
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Affiliation(s)
- Aaron Coffin
- Department of Biochemistry, Division of Chemistry , UT Southwestern Medical Center , 5323 Harry Hines Blvd. , Dallas , Texas 75390-0938 , United States
| | - Joseph M Ready
- Department of Biochemistry, Division of Chemistry , UT Southwestern Medical Center , 5323 Harry Hines Blvd. , Dallas , Texas 75390-0938 , United States
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10
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Mukherjee S, Biju AT. Recent Advances in the Organocatalytic Enantioselective Synthesis of Functionalized β-Lactones. Chem Asian J 2018; 13:2333-2349. [DOI: 10.1002/asia.201800902] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/20/2018] [Indexed: 01/25/2023]
Affiliation(s)
- Subrata Mukherjee
- Organic Chemistry Division; CSIR-National Chemical Laboratory; Dr. Homi Bhabha Road Pune 411008 India
| | - Akkattu T. Biju
- Department of Organic Chemistry; Indian Institute of Science; Bangalore 560012 India
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11
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(-)-Homosalinosporamide A and Its Mode of Proteasome Inhibition: An X-ray Crystallographic Study. Mar Drugs 2018; 16:md16070240. [PMID: 30029468 PMCID: PMC6071143 DOI: 10.3390/md16070240] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/05/2018] [Accepted: 07/11/2018] [Indexed: 12/18/2022] Open
Abstract
Upon acylation of the proteasome by the β-lactone inhibitor salinosporamide A (SalA), tetrahydrofuran formation occurs by intramolecular alkylation of the incipient alkoxide onto the choroethyl sidechain and irreversibly blocks the active site. Our previously described synthetic approach to SalA, utilizing a bioinspired, late-stage, aldol-β-lactonization strategy to construct the bicyclic β-lactone core, enabled synthesis of (⁻)-homosalinosporamide A (homoSalA). This homolog was targeted to determine whether an intramolecular tetrahydropyran is formed in a similar manner to SalA. Herein, we report the X-ray structure of the yeast 20S proteasome:homoSalA-complex which reveals that tetrahydropyran ring formation does not occur despite comparable potency at the chymotrypsin-like active site in a luminogenic enzyme assay. Thus, the natural product derivative homoSalA blocks the proteasome by a covalent reversible mode of action, opening the door for further fine-tuning of proteasome inhibition.
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12
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Wu X, Wang HJ, Huang YS, Li WDZ. Intramolecular [2 + 2] Cycloadditions of Alkyl(phenylthio)ketenes: Total Synthesis of (+)-Sphaerodiol. Org Lett 2018. [PMID: 29533070 DOI: 10.1021/acs.orglett.8b00407] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Asymmetric total synthesis of (+)-sphaerodiol (2) has been achieved. A key step is an intramolecular [2 + 2] cycloaddition of alkyl(phenylthio)ketene for rapid assembly of the decalin ring.
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Affiliation(s)
- Xiang Wu
- Anhui Province Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, School of Chemistry and Chemical Engineering , Hefei University of Technology , Hefei 230009 , China
| | - Hai-Jun Wang
- Anhui Province Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, School of Chemistry and Chemical Engineering , Hefei University of Technology , Hefei 230009 , China
| | - Yong-Shuang Huang
- Anhui Province Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, School of Chemistry and Chemical Engineering , Hefei University of Technology , Hefei 230009 , China
| | - Wei-Dong Z Li
- School of Life Science and Engineering , Southwest Jiaotong University , Chengdu 610031 , China
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13
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Van KN, Romo D. Multicomponent, Enantioselective Michael-Michael-Aldol-β-Lactonizations Delivering Complex β-Lactones. J Org Chem 2018; 83:632-643. [PMID: 29219311 DOI: 10.1021/acs.joc.7b02543] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Optically active, tertiary amine Lewis bases react with unsaturated acid chlorides to deliver chiral, α,β-unsaturated acylammonium salts. These intermediates participate in a catalytic, enantioselective, three-component process delivering bi- and tricyclic β-lactones through a Michael-Michael-aldol-β-lactonization. In a single operation, the described multicomponent, organocascade process forms complex bi- and tricyclic β-lactones by generating four new bonds, two rings, and up to four contiguous stereocenters. In the racemic series, yields of 22-75% were achieved using 4-pyrrolidinopyridine as Lewis base. In the enantioselective series employing isothiourea catalysts, a kinetic resolution of the initially formed racemic Michael adduct appears operative, providing yields of 46% to quantitative (based on 50% max) with up to 94:6 er. Some evidence for a dynamic kinetic asymmetric transformation for tricyclic-β-lactone 1d was obtained following optimization (yields up to 61%, 94:6 er) through a presumed reversible Michael.
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Affiliation(s)
- Khoi N Van
- Department of Chemistry, Texas A&M University , College Station, Texas 77842, United States
| | - Daniel Romo
- Department of Chemistry & Biochemistry, Baylor University , Waco, Texas 76798, United States
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14
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Arokianathar JN, Frost AB, Slawin AMZ, Stead D, Smith AD. Isothiourea-Catalyzed Enantioselective Addition of 4-Nitrophenyl Esters to Iminium Ions. ACS Catal 2018. [DOI: 10.1021/acscatal.7b02697] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Jude N. Arokianathar
- EaStCHEM,
School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, United Kingdom
| | - Aileen B. Frost
- EaStCHEM,
School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, United Kingdom
| | - Alexandra M. Z. Slawin
- EaStCHEM,
School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, United Kingdom
| | - Darren Stead
- Medicinal Chemistry, Oncology, IMED Biotech Unit, AstraZeneca, Cambridge, United Kingdom
| | - Andrew D. Smith
- EaStCHEM,
School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, United Kingdom
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15
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Kong W, Romo D. Diastereo- and Enantioselective Synthesis of Bi- and Tricyclic N-Heterocycle-Fused β-Lactones. J Org Chem 2017; 82:13161-13170. [DOI: 10.1021/acs.joc.7b02235] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Weixu Kong
- Department of Chemistry & Biochemistry, Baylor University, Waco, Texas 76710, United States
| | - Daniel Romo
- Department of Chemistry & Biochemistry, Baylor University, Waco, Texas 76710, United States
- Department of Chemistry, Texas A&M University, College Station, Texas 77840, United States
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16
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Daniel Romo. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/anie.201703689] [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]
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17
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18
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Mondal S, Mukherjee S, Das TK, Gonnade RG, Biju AT. Enantioselective Synthesis of Functionalized β-Lactones by NHC-Catalyzed Aldol Lactonization of Ketoacids. J Org Chem 2017; 82:9223-9228. [PMID: 28774172 DOI: 10.1021/acs.joc.7b01526] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
N-Heterocyclic carbene (NHC)-catalyzed intramolecular aldol lactonization of readily available ketoacids leading to the enantioselective synthesis of cyclopentane-fused β-lactones is presented. The reaction proceeds via the generation of NHC-bound enolate intermediates formed from the ketoacids in the presence of the peptide coupling reagent HATU and NHC generated from the chiral triazolium salt. The functionalized β-lactones are formed under mild conditions in high yields and enantioselectivities.
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Affiliation(s)
- Santigopal Mondal
- Academy of Scientific and Innovative Research (AcSIR) , New Delhi 110020, India
| | - Subrata Mukherjee
- Academy of Scientific and Innovative Research (AcSIR) , New Delhi 110020, India
| | - Tamal Kanti Das
- Academy of Scientific and Innovative Research (AcSIR) , New Delhi 110020, India
| | | | - Akkattu T Biju
- Academy of Scientific and Innovative Research (AcSIR) , New Delhi 110020, India
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19
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Lu X, Ge L, Cheng C, Chen J, Cao W, Wu X. Enantioselective Cascade Reaction for Synthesis of Quinolinones through Synergistic Catalysis Using Cu-Pybox and Chiral Benzotetramisole as Catalysts. Chemistry 2017; 23:7689-7693. [DOI: 10.1002/chem.201701741] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Indexed: 01/13/2023]
Affiliation(s)
- Xuehe Lu
- Department of Chemistry, College of Sciences; Shanghai University; 99 Shangda Lu Shanghai 200444 P. R. China
| | - Luo Ge
- Department of Chemistry, College of Sciences; Shanghai University; 99 Shangda Lu Shanghai 200444 P. R. China
| | - Cang Cheng
- Department of Chemistry, College of Sciences; Shanghai University; 99 Shangda Lu Shanghai 200444 P. R. China
| | - Jie Chen
- Department of Chemistry, College of Sciences; Shanghai University; 99 Shangda Lu Shanghai 200444 P. R. China
| | - Weiguo Cao
- Department of Chemistry, College of Sciences; Shanghai University; 99 Shangda Lu Shanghai 200444 P. R. China
| | - Xiaoyu Wu
- Department of Chemistry, College of Sciences; Shanghai University; 99 Shangda Lu Shanghai 200444 P. R. China
- Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry; Chinese Academy of Sciences; 345 Lingling Lu Shanghai 200032 P. R. China
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20
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Mondal S, Mukherjee S, Das TK, Gonnade R, Biju AT. N-Heterocyclic Carbene-Catalyzed Aldol-Lactonization of Ketoacids via Dynamic Kinetic Resolution. ACS Catal 2017. [DOI: 10.1021/acscatal.7b00681] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Santigopal Mondal
- Academy of Scientific
and Innovative Research (AcSIR), New Delhi 110020, India
| | - Subrata Mukherjee
- Academy of Scientific
and Innovative Research (AcSIR), New Delhi 110020, India
| | - Tamal Kanti Das
- Academy of Scientific
and Innovative Research (AcSIR), New Delhi 110020, India
| | | | - Akkattu T. Biju
- Academy of Scientific
and Innovative Research (AcSIR), New Delhi 110020, India
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21
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Jin JH, Li XY, Luo X, Fossey JS, Deng WP. Asymmetric Synthesis of cis-3,4-Dihydrocoumarins via [4 + 2] Cycloadditions Catalyzed by Amidine Derivatives. J Org Chem 2017; 82:5424-5432. [PMID: 28441490 DOI: 10.1021/acs.joc.7b00367] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A highly efficient chiral amidine derivative-catalyzed tandem Michael addition/lactonization of carboxylic acids and o-quinone methides (o-QMs) has been developed that enables the asymmetric synthesis of cis-3,4-dihydrocoumarins bearing contiguous tertiary stereogenic centers in high yields with excellent stereoselectivities.
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Affiliation(s)
- Jing-Hai Jin
- School of Pharmacy and Shanghai Key Laboratory of New Drug Design, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, China
| | - Xiang-Yu Li
- School of Pharmacy and Shanghai Key Laboratory of New Drug Design, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, China
| | - Xiaoyan Luo
- School of Pharmacy and Shanghai Key Laboratory of New Drug Design, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, China
| | - John S Fossey
- School of Chemistry, University of Birmingham , Edgbaston, Birmingham, West Midlands B15 2TT, United Kingdom
| | - Wei-Ping Deng
- School of Pharmacy and Shanghai Key Laboratory of New Drug Design, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, China
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22
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Affiliation(s)
- Rong Tong
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University, 635 Prices Fork Road, Blacksburg, Virginia 24061, United States
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23
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Song J, Zhang ZJ, Gong LZ. Asymmetric [4+2] Annulation of C1 Ammonium Enolates with Copper-Allenylidenes. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201700105] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- 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
| | - Zi-Jing Zhang
- 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
- Collaborative Innovation Center of Chemical Science and Engineering; Tianjin China
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24
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Song J, Zhang ZJ, Gong LZ. Asymmetric [4+2] Annulation of C1 Ammonium Enolates with Copper-Allenylidenes. Angew Chem Int Ed Engl 2017; 56:5212-5216. [DOI: 10.1002/anie.201700105] [Citation(s) in RCA: 132] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/16/2017] [Indexed: 11/09/2022]
Affiliation(s)
- 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
| | - Zi-Jing Zhang
- 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
- Collaborative Innovation Center of Chemical Science and Engineering; Tianjin China
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25
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Cao J, Dong S, Jiang D, Zhu P, Zhang H, Li R, Li Z, Wang X, Tang W, Du D. β-Functionalization of Indolin-2-one-Derived Aliphatic Acids for the Divergent Synthesis of Spirooxindole γ-Butyrolactones. J Org Chem 2017; 82:4186-4193. [PMID: 28326774 DOI: 10.1021/acs.joc.7b00153] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
β-Functionalization of indolin-2-one-derived aliphatic acids has been applied in formal [3 + 2] annualtions for catalyst-free and divergent synthesis of two series of structurally interesting 3,3'-spirooxindole γ-butyrolactones that may be attractive for potential drug discovery. These findings also pave the way for further diversity-oriented synthesis of spirooxindoles starting from indolin-2-one-derived aliphatic acids or their derivatives.
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Affiliation(s)
- Jing Cao
- State Key Laboratory of Natural Medicines, Department of Organic Chemistry, China Pharmaceutical University , Nanjing, 210009, P. R. China
| | - Shuding Dong
- State Key Laboratory of Natural Medicines, Department of Organic Chemistry, China Pharmaceutical University , Nanjing, 210009, P. R. China
| | - Delu Jiang
- State Key Laboratory of Natural Medicines, Department of Organic Chemistry, China Pharmaceutical University , Nanjing, 210009, P. R. China
| | - Peiyu Zhu
- State Key Laboratory of Natural Medicines, Department of Organic Chemistry, China Pharmaceutical University , Nanjing, 210009, P. R. China
| | - Han Zhang
- State Key Laboratory of Natural Medicines, Department of Organic Chemistry, China Pharmaceutical University , Nanjing, 210009, P. R. China
| | - Rui Li
- State Key Laboratory of Natural Medicines, Department of Organic Chemistry, China Pharmaceutical University , Nanjing, 210009, P. R. China
| | - Zhanyi Li
- State Key Laboratory of Natural Medicines, Department of Organic Chemistry, China Pharmaceutical University , Nanjing, 210009, P. R. China
| | - Xuanyu Wang
- State Key Laboratory of Natural Medicines, Department of Organic Chemistry, China Pharmaceutical University , Nanjing, 210009, P. R. China
| | - Weifang Tang
- State Key Laboratory of Natural Medicines, Department of Organic Chemistry, China Pharmaceutical University , Nanjing, 210009, P. R. China
| | - Ding Du
- State Key Laboratory of Natural Medicines, Department of Organic Chemistry, China Pharmaceutical University , Nanjing, 210009, P. R. China
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26
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Wu X, Hao L, Zhang Y, Rakesh M, Reddi RN, Yang S, Song BA, Chi YR. Construction of Fused Pyrrolidines and β-Lactones by Carbene-Catalyzed C-N, C-C, and C-O Bond Formations. Angew Chem Int Ed Engl 2017; 56:4201-4205. [PMID: 28295941 DOI: 10.1002/anie.201700045] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 02/12/2017] [Indexed: 01/25/2023]
Abstract
A carbene-catalyzed intermolecular C-N bond formation, which initiates a highly selective cascade reaction for the synthesis of pyrrolidine fused β-lactones, is disclosed. The nitrogen-containing bicyclic β-lactone products are obtained with good yields and excellent stereoselectivities. Synthetic transformations of the reaction products into useful functional molecules, such as amino catalysts, can be efficiently realized under mild reaction conditions. Mechanistically, this study provides insights into modulating the reactivities of heteroatoms, such as nitrogen atoms, in challenging carbene-catalyzed asymmetric carbon-heteroatom bond-forming reactions.
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Affiliation(s)
- Xingxing Wu
- Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Lin Hao
- Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Yuexia Zhang
- Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Maiti Rakesh
- Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Rambabu N Reddi
- Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Song Yang
- Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Bao-An Song
- Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Yonggui Robin Chi
- Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.,Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
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27
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Wu X, Hao L, Zhang Y, Rakesh M, Reddi RN, Yang S, Song BA, Chi YR. Construction of Fused Pyrrolidines and β-Lactones by Carbene-Catalyzed C−N, C−C, and C−O Bond Formations. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201700045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Xingxing Wu
- Division of Chemistry & Biological Chemistry; School of Physical & Mathematical Sciences; Nanyang Technological University; Singapore 637371 Singapore
| | - Lin Hao
- Division of Chemistry & Biological Chemistry; School of Physical & Mathematical Sciences; Nanyang Technological University; Singapore 637371 Singapore
| | - Yuexia Zhang
- Division of Chemistry & Biological Chemistry; School of Physical & Mathematical Sciences; Nanyang Technological University; Singapore 637371 Singapore
| | - Maiti Rakesh
- Division of Chemistry & Biological Chemistry; School of Physical & Mathematical Sciences; Nanyang Technological University; Singapore 637371 Singapore
| | - Rambabu N. Reddi
- Division of Chemistry & Biological Chemistry; School of Physical & Mathematical Sciences; Nanyang Technological University; Singapore 637371 Singapore
| | - Song Yang
- Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering; Key Laboratory of Green Pesticide and Agricultural Bioengineering; Ministry of Education; Guizhou University; Huaxi District Guiyang 550025 China
| | - Bao-An Song
- Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering; Key Laboratory of Green Pesticide and Agricultural Bioengineering; Ministry of Education; Guizhou University; Huaxi District Guiyang 550025 China
| | - Yonggui Robin Chi
- Division of Chemistry & Biological Chemistry; School of Physical & Mathematical Sciences; Nanyang Technological University; Singapore 637371 Singapore
- Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering; Key Laboratory of Green Pesticide and Agricultural Bioengineering; Ministry of Education; Guizhou University; Huaxi District Guiyang 550025 China
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28
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Neyyappadath RM, Cordes DB, Slawin AMZ, Smith AD. 6-exo-trig Michael addition-lactonizations for catalytic enantioselective chromenone synthesis. Chem Commun (Camb) 2017; 53:2555-2558. [PMID: 28133660 PMCID: PMC5358503 DOI: 10.1039/c6cc10178j] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 01/18/2017] [Indexed: 11/30/2022]
Abstract
The catalytic enantioselective 6-exo-trig Michael addition-lactonization of enone-acid substrates to form cis-chromenones with high diastereo- and enantiocontrol was developed using the commercially available isothiourea tetramisole. An acidic workup proved necessary to minimize product epimerization and maximize product er, providing cis-chromenones in excellent yield, and with excellent diastereo- and enantioselectivity.
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Affiliation(s)
- Rifahath M Neyyappadath
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, UK.
| | - David B Cordes
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, UK.
| | - Alexandra M Z Slawin
- 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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29
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Levens A, Ametovski A, Lupton DW. Enantioselective (4+2) Annulation of Donor-Acceptor Cyclobutanes by N-Heterocyclic Carbene Catalysis. Angew Chem Int Ed Engl 2016; 55:16136-16140. [PMID: 27891746 DOI: 10.1002/anie.201609330] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 10/31/2016] [Indexed: 12/22/2022]
Abstract
Herein we report the enantioselective (4+2) annulation of donor-acceptor cyclobutanes and unsaturated acyl fluorides using N-heterocyclic carbene catalysis. The reaction allows a 3-step synthesis of cyclohexyl β-lactones (25 examples) in excellent chemical yield (most ≥90 %) and stereochemical integrity (all >20:1 d.r., most ≥97:3 e.r.). Mechanistic studies support ester enolate Claisen rearrangement, while derivatizations provide functionalized cyclohexenes and dihydroquinolinones.
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Affiliation(s)
- Alison Levens
- School of Chemistry, Monash University, Clayton, 3800, Victoria, Australia
| | - Adam Ametovski
- School of Chemistry, Monash University, Clayton, 3800, Victoria, Australia
| | - David W Lupton
- School of Chemistry, Monash University, Clayton, 3800, Victoria, Australia
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30
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Levens A, Ametovski A, Lupton DW. Enantioselective (4+2) Annulation of Donor-Acceptor Cyclobutanes by N-Heterocyclic Carbene Catalysis. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201609330] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Alison Levens
- School of Chemistry; Monash University; Clayton 3800 Victoria Australia
| | - Adam Ametovski
- School of Chemistry; Monash University; Clayton 3800 Victoria Australia
| | - David W. Lupton
- School of Chemistry; Monash University; Clayton 3800 Victoria Australia
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31
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Vellalath S, Romo D. Asymmetric Organocatalysis: The Emerging Utility of α,β-Unsaturated Acylammonium Salts. Angew Chem Int Ed Engl 2016; 55:13934-13943. [PMID: 27650693 PMCID: PMC5523468 DOI: 10.1002/anie.201602217] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/12/2016] [Indexed: 11/06/2022]
Abstract
Although acylammonium salts are well-studied, chiral α,β-unsaturated acylammonium salts have received much less attention. While these intermediates are convenient synthons, which are readily available from several commodity unsaturated acids and acid chlorides, and possess three reactive sites, their application in organic synthesis has been limited because of the lack of appropriate chiral Lewis bases for their generation. In recent years, the utility of chiral, unsaturated acylammonium salts has expanded considerably, thus demonstrating the unique reactivity of this intermediate leading to the development of a diverse array of catalytic, asymmetric transformations including organocascade processes. This Minireview highlights the recent and growing interest in these intermediates which might spark further research into their untapped potential for asymmetric organocascade catalysis. A cursory comparison is made to related unsaturated iminium and acylazolium intermediates.
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Affiliation(s)
- Sreekumar Vellalath
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, 76798, USA
| | - Daniel Romo
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, 76798, USA.
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32
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Young CM, Stark DG, West TH, Taylor JE, Smith AD. Exploiting the Imidazolium Effect in Base-free Ammonium Enolate Generation: Synthetic and Mechanistic Studies. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201608046] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Claire M. Young
- EaStCHEM, School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
| | - Daniel G. Stark
- EaStCHEM, School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
| | - Thomas H. West
- EaStCHEM, School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
| | - James E. Taylor
- EaStCHEM, School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
| | - Andrew D. Smith
- EaStCHEM, School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
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33
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Young CM, Stark DG, West TH, Taylor JE, Smith AD. Exploiting the Imidazolium Effect in Base-free Ammonium Enolate Generation: Synthetic and Mechanistic Studies. Angew Chem Int Ed Engl 2016; 55:14394-14399. [DOI: 10.1002/anie.201608046] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 09/22/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Claire M. Young
- EaStCHEM, School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
| | - Daniel G. Stark
- EaStCHEM, School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
| | - Thomas H. West
- EaStCHEM, School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
| | - James E. Taylor
- EaStCHEM, School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
| | - Andrew D. Smith
- EaStCHEM, School of Chemistry; University of St Andrews; North Haugh St Andrews Fife KY16 9ST UK
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34
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Stark DG, Williamson P, Gayner ER, Musolino SF, Kerr RWF, Taylor JE, Slawin AMZ, O'Riordan TJC, Macgregor SA, Smith AD. Isothiourea-catalysed enantioselective pyrrolizine synthesis: synthetic and computational studies. Org Biomol Chem 2016; 14:8957-65. [PMID: 27489030 PMCID: PMC5314687 DOI: 10.1039/c6ob01557c] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 07/21/2016] [Indexed: 11/21/2022]
Abstract
The catalytic enantioselective synthesis of a range of cis-pyrrolizine carboxylate derivatives with outstanding stereocontrol (14 examples, >95 : 5 dr, >98 : 2 er) through an isothiourea-catalyzed intramolecular Michael addition-lactonisation and ring-opening approach from the corresponding enone acid is reported. An optimised and straightforward three-step synthetic route to the enone acid starting materials from readily available pyrrole-2-carboxaldehydes is delineated, with benzotetramisole (5 mol%) proving the optimal catalyst for the enantioselective process. Ring-opening of the pyrrolizine dihydropyranone products with either MeOH or a range of amines leads to the desired products in excellent yield and enantioselectivity. Computation has been used to probe the factors leading to high stereocontrol, with the formation of the observed cis-steroisomer predicted to be kinetically and thermodynamically favoured.
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Affiliation(s)
- Daniel G. Stark
- EaStCHEM , School of Chemistry , University of St Andrews , North Haugh , St Andrews , Fife KY16 9ST , UK .
| | - Patrick Williamson
- EaStCHEM , School of Chemistry , University of St Andrews , North Haugh , St Andrews , Fife KY16 9ST , UK .
| | - Emma R. Gayner
- Institute of Chemical Sciences , Heriot-Watt University , Edinburgh , EH14 4AS , UK .
| | - Stefania F. Musolino
- EaStCHEM , School of Chemistry , University of St Andrews , North Haugh , St Andrews , Fife KY16 9ST , UK .
| | - Ryan W. F. Kerr
- EaStCHEM , School of Chemistry , University of St Andrews , North Haugh , St Andrews , Fife KY16 9ST , UK .
| | - James E. Taylor
- 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 .
| | | | - Stuart A. Macgregor
- Institute of Chemical Sciences , Heriot-Watt University , Edinburgh , EH14 4AS , UK .
| | - Andrew D. Smith
- EaStCHEM , School of Chemistry , University of St Andrews , North Haugh , St Andrews , Fife KY16 9ST , UK .
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35
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Mandal S, Mandal S, Ghosh SK, Ghosh A, Saha R, Banerjee S, Saha B. Review of the aldol reaction. SYNTHETIC COMMUN 2016. [DOI: 10.1080/00397911.2016.1206938] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Swagata Mandal
- Homogeneous Catalysis Laboratory, Department of Chemistry, University of Burdwan, Golapbag, Burdwan, India
| | - Sangita Mandal
- Homogeneous Catalysis Laboratory, Department of Chemistry, University of Burdwan, Golapbag, Burdwan, India
| | - Sumanta K. Ghosh
- Homogeneous Catalysis Laboratory, Department of Chemistry, University of Burdwan, Golapbag, Burdwan, India
| | - Aniruddha Ghosh
- Homogeneous Catalysis Laboratory, Department of Chemistry, University of Burdwan, Golapbag, Burdwan, India
| | - Rumpa Saha
- Department of Chemistry, TDB College Raniganj, Raniganj, India
| | | | - Bidyut Saha
- Homogeneous Catalysis Laboratory, Department of Chemistry, University of Burdwan, Golapbag, Burdwan, India
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36
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Stark DG, Young CM, O'Riordan TJC, Slawin AMZ, Smith AD. Enantioselective isothiourea-catalysed trans-dihydropyridinone synthesis using saccharin-derived ketimines: scope and limitations. Org Biomol Chem 2016; 14:8068-73. [PMID: 27492887 DOI: 10.1039/c6ob01473a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The catalytic enantioselective synthesis of a range of trans-dihydropyridinones from aryl-, heteroaryl- and alkenylacetic acids and saccharin-derived ketimines with good to excellent stereocontrol (15 examples, up to >95 : 5 dr, up to >99 : 1 er) is reported. After extensive optimisation, HyperBTM proved the optimal isothiourea catalyst for this transformation at -78 °C, giving trans-dihydropyridones with generally excellent levels of diastereo- and enantioselectivity.
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Affiliation(s)
- Daniel G Stark
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK.
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37
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Chisholm R, Parkin JD, Smith AD, Hähner G. Isothiourea-Mediated Organocatalytic Michael Addition-Lactonization on a Surface: Modification of SAMs on Silicon Oxide Substrates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:3130-3138. [PMID: 27015037 DOI: 10.1021/acs.langmuir.5b04686] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Tailoring the functionality of self-assembled monolayers (SAMs) can be achieved either by depositing prefunctionalized molecules with the appropriate terminal groups or by chemical modification of an existing SAM in situ. The latter approach is particularly advantageous to allow for diversity of surface functionalization from a single SAM and if the incorporation of bulky groups is desired. In the present study an organocatalytic isothiourea-mediated Michael addition-lactonization process analogous to a previously reported study in solution is presented. An achiral isothiourea, 3,4-dihydro-2H-pyrimido[2,1-b]benzothiazole (DHPB), promotes the intermolecular Michael addition-lactonization of a trifluoromethylenone terminated SAM and a variety of arylacetic acids affording C(6)-trifluoromethyldihydropyranones tethered to the surface. X-ray photoelectron spectroscopy, atomic force microscopy, contact angle, and ellipsometry analysis were conducted to confirm the presence of the substituted dihydropyranone. A model study of this approach was also performed in solution to probe the reaction diastereoselectivity as it cannot be measured directly on the surface.
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Affiliation(s)
- Ross Chisholm
- EaStCHEM School of Chemistry, University of St. Andrews , North Haugh, St. Andrews KY16 9ST, U.K
| | - John D Parkin
- 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
| | - Georg Hähner
- EaStCHEM School of Chemistry, University of St. Andrews , North Haugh, St. Andrews KY16 9ST, U.K
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38
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Affiliation(s)
- Liang Hong
- School
of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006 China
| | - Wangsheng Sun
- Key
Laboratory of Preclinical Study for New Drugs of Gansu Province, Lanzhou University, Lanzhou, 730000 China
| | - Dongxu Yang
- Key
Laboratory of Preclinical Study for New Drugs of Gansu Province, Lanzhou University, Lanzhou, 730000 China
| | - Guofeng Li
- Key
Laboratory of Preclinical Study for New Drugs of Gansu Province, Lanzhou University, Lanzhou, 730000 China
| | - Rui Wang
- School
of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006 China
- Key
Laboratory of Preclinical Study for New Drugs of Gansu Province, Lanzhou University, Lanzhou, 730000 China
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39
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Fugard AJ, Thompson BK, Slawin AMZ, Taylor JE, Smith AD. Organocatalytic Synthesis of Fused Bicyclic 2,3-Dihydro-1,3,4-oxadiazoles through an Intramolecular Cascade Cyclization. Org Lett 2015; 17:5824-7. [PMID: 26598296 DOI: 10.1021/acs.orglett.5b02997] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hydrazone-carboxylic acids undergo intramolecular cyclization in the presence of pivaloyl chloride, iPr(2)NEt, and catalytic DABCO to form a range of substituted fused tricyclic 2,3-dihydro-1,3,4-oxadiazoles in high yields.
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Affiliation(s)
- Alison J Fugard
- EaStCHEM, School of Chemistry, University of St. Andrews , North Haugh, St. Andrews, KY16 9ST, U.K
| | - Bethany K Thompson
- EaStCHEM, School of Chemistry, University of St. Andrews , North Haugh, St. Andrews, KY16 9ST, U.K
| | - Alexandra M Z Slawin
- EaStCHEM, School of Chemistry, University of St. Andrews , North Haugh, St. Andrews, KY16 9ST, U.K
| | - James E Taylor
- 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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40
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Stark DG, Morrill LC, Cordes DB, Slawin AMZ, O'Riordan TJC, Smith AD. Enantioselective Synthesis of 3,5,6-Substituted Dihydropyranones and Dihydropyridinones using Isothiourea-Mediated Catalysis. Chem Asian J 2015; 11:395-400. [PMID: 26471245 PMCID: PMC4755233 DOI: 10.1002/asia.201500907] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Indexed: 02/02/2023]
Abstract
The scope of dihydropyranone and dihydropyridinone products accessible by isothiourea-catalyzed processes has been expanded and explored through the use of 2-N-tosyliminoacrylates and 2-aroylacrylates in a Michael addition-lactonization/lactamization cascade reaction. Notably, to ensure reproducibility it is essential to use homoanhydrides as ammonium enolate precursors with 2-aroyl acrylates, while carboxylic acids can be used with 2-N-tosyliminoacrylates, delivering a range of 3,5,6-substituted dihydropyranones and dihydropyridinones with high enantioselectivity (typically >90 % ee). The derivatization of the heterocyclic core of a 3,5,6-substituted dihydropyranone through hydrogenation is also reported.
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Affiliation(s)
- Daniel G Stark
- School of Chemistry, University of St Andrews, North Haugh, St Andrews Fife, KY16 9ST, UK
| | - Louis C Morrill
- School of Chemistry, University of St Andrews, North Haugh, St Andrews Fife, KY16 9ST, UK
| | - David B Cordes
- School of Chemistry, University of St Andrews, North Haugh, St Andrews Fife, KY16 9ST, UK
| | - Alexandra M Z Slawin
- School of Chemistry, University of St Andrews, North Haugh, St Andrews Fife, KY16 9ST, UK
| | - Timothy J C O'Riordan
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire, RG42 6EY, UK
| | - Andrew D Smith
- School of Chemistry, University of St Andrews, North Haugh, St Andrews Fife, KY16 9ST, UK.
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41
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Jin Z, Jiang K, Fu Z, Torres J, Zheng P, Yang S, Song BA, Chi YR. Nucleophilic β-Carbon Activation of Propionic Acid as a 3-Carbon Synthon by Carbene Organocatalysis. Chemistry 2015; 21:9360-3. [PMID: 26013883 DOI: 10.1002/chem.201501481] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Indexed: 12/17/2022]
Abstract
Direct β-carbon activation of propionic acid (C2H5CO2H) by carbene organocatalysis has been developed. This activation affords the smallest azolium homoenolate intermediate (without any substituent) as a 3-carbon nucleophile for enantioselective reactions. Propionic acid is an excellent raw material because it is cheap, stable, and safe. This approach provides a much better solution to azolium homoenolate synthesis than the previously established use of acrolein (enal without any substituent), which is expensive, unstable, and toxic.
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Affiliation(s)
- Zhichao Jin
- Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)
| | - Ke Jiang
- School of Biological Sciences, Nanyang Technological University, Singapore 637371 (Singapore)
| | - Zhenqian Fu
- Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)
| | - Jaume Torres
- School of Biological Sciences, Nanyang Technological University, Singapore 637371 (Singapore)
| | - Pengcheng Zheng
- Laboratory Breeding Base of Green Pesticide and Agricultural, Bioengineering, Key Laboratory of Green Pesticide and Agricultural, Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025 (P. R. China)
| | - Song Yang
- Laboratory Breeding Base of Green Pesticide and Agricultural, Bioengineering, Key Laboratory of Green Pesticide and Agricultural, Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025 (P. R. China)
| | - Bao-An Song
- Laboratory Breeding Base of Green Pesticide and Agricultural, Bioengineering, Key Laboratory of Green Pesticide and Agricultural, Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025 (P. R. China).
| | - Yonggui Robin Chi
- Laboratory Breeding Base of Green Pesticide and Agricultural, Bioengineering, Key Laboratory of Green Pesticide and Agricultural, Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025 (P. R. China).
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42
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Morrill LC, Smith AD. Organocatalytic Lewis base functionalisation of carboxylic acids, esters and anhydrides via C1-ammonium or azolium enolates. Chem Soc Rev 2015; 43:6214-26. [PMID: 24867308 DOI: 10.1039/c4cs00042k] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This tutorial review highlights the organocatalytic Lewis base functionalisation of carboxylic acids, esters and anhydrides via C1-ammonium/azolium enolates. The generation and synthetic utility of these powerful intermediates is highlighted through their application in various methodologies including aldol-lactonisations, Michael-lactonisations/lactamisations and [2,3]-rearrangements.
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Affiliation(s)
- Louis C Morrill
- EastCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, UKKY16 9ST.
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43
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Xie Y, Yu C, Li T, Tu S, Yao C. An NHC-catalyzed in situ activation strategy to β-functionalize saturated carboxylic acid: an enantioselective formal [3+2] annulation for spirocyclic oxindolo-γ-butyrolactones. Chemistry 2015; 21:5355-9. [PMID: 25689040 DOI: 10.1002/chem.201500345] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Indexed: 01/07/2023]
Abstract
An in situ NHC-catalyzed activation strategy to β-functionalize saturated carboxylic acid was developed. This asymmetric formal [3+2] annulation could deliver spirocyclic oxindolo-γ-butyrolactones from saturated carboxylic acid and isatin in good yields with high to excellent enantioselectivities. The easy availability of the starting materials, direct installation of functional units at unreactive carbon atom and the convergent assembly make this protocol attractive in the field of organic synthesis.
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Affiliation(s)
- Yuanwei Xie
- School of Chemistry and Chemical Engineering, Jiangsu Key Lab of Green Synthetic Chemistry for Functional Materials, Jiangsu Normal University, Xuzhou, Jiangsu 221116 (P.R. China)
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44
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Hesping L, Biswas A, Daniliuc CG, Mück-Lichtenfeld C, Studer A. Stereoselective Lewis base catalyzed formal 1,3-dipolar cycloaddition of azomethine imines with mixed anhydrides. Chem Sci 2015; 6:1252-1257. [PMID: 29541440 PMCID: PMC5811128 DOI: 10.1039/c4sc02612h] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 11/14/2014] [Indexed: 11/21/2022] Open
Abstract
Stereoselective synthesis of pyrazolidinones via dipolar cycloaddition of azomethine imines with active esters under Lewis base catalysis is presented. The active esters are readily generated in situ from the corresponding acids. Products, which are obtained with excellent diastereocontrol and high enantioselectivity, contain along with the pyrazolidinone core also the tetrahydroisoquinoline structural motif. Theoretical studies give insight into the mechanism of the formal cycloaddition reaction.
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Affiliation(s)
- Lena Hesping
- Organisch-Chemisches Institut , Westfälische Wilhelms-Universität Münster Corrensstrasse 40 , 48149 Münster , Germany . ; http://www.uni-muenster.de/Chemie.oc/studer/ ; ; Tel: +49-251-83-33291
| | - Anup Biswas
- Organisch-Chemisches Institut , Westfälische Wilhelms-Universität Münster Corrensstrasse 40 , 48149 Münster , Germany . ; http://www.uni-muenster.de/Chemie.oc/studer/ ; ; Tel: +49-251-83-33291
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut , Westfälische Wilhelms-Universität Münster Corrensstrasse 40 , 48149 Münster , Germany . ; http://www.uni-muenster.de/Chemie.oc/studer/ ; ; Tel: +49-251-83-33291
| | - Christian Mück-Lichtenfeld
- Organisch-Chemisches Institut , Westfälische Wilhelms-Universität Münster Corrensstrasse 40 , 48149 Münster , Germany . ; http://www.uni-muenster.de/Chemie.oc/studer/ ; ; Tel: +49-251-83-33291
| | - Armido Studer
- Organisch-Chemisches Institut , Westfälische Wilhelms-Universität Münster Corrensstrasse 40 , 48149 Münster , Germany . ; http://www.uni-muenster.de/Chemie.oc/studer/ ; ; Tel: +49-251-83-33291
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45
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Yeh PP, Daniels DSB, Fallan C, Gould E, Simal C, Taylor JE, Slawin AMZ, Smith AD. Exploring the scope of the isothiourea-mediated synthesis of dihydropyridinones. Org Biomol Chem 2015; 13:2177-91. [DOI: 10.1039/c4ob02408g] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The exploration and expansion of the scope of the isothiourea-mediated synthesis of dihydropyridinones is presented.
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Affiliation(s)
- Pei-Pei Yeh
- EaStCHEM
- School of Chemistry
- University of St Andrews
- North Haugh
- UK
| | | | - Charlene Fallan
- EaStCHEM
- School of Chemistry
- University of St Andrews
- North Haugh
- UK
| | - Eoin Gould
- EaStCHEM
- School of Chemistry
- University of St Andrews
- North Haugh
- UK
| | - Carmen Simal
- EaStCHEM
- School of Chemistry
- University of St Andrews
- North Haugh
- UK
| | - James E. Taylor
- EaStCHEM
- School of Chemistry
- University of St Andrews
- North Haugh
- UK
| | | | - Andrew D. Smith
- EaStCHEM
- School of Chemistry
- University of St Andrews
- North Haugh
- UK
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46
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Cheng JT, Chen XY, Ye S. N-heterocyclic carbene-catalyzed cyclocondensation of 2-aryl carboxylic acids and enones: highly enantioselective synthesis of δ-lactones. Org Biomol Chem 2015; 13:1313-6. [DOI: 10.1039/c4ob02330g] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The NHC-catalyzed [4 + 2] cyclocondensation of 2-aryl carboxylic acids with enones was developed, giving δ-lactones in good yields with high enantioselectivities.
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Affiliation(s)
- Jin-Tang Cheng
- Beijing National Laboratory for Molecular Sciences
- Key Laboratory of Molecular Recognition and Function
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
| | - Xiang-Yu Chen
- Beijing National Laboratory for Molecular Sciences
- Key Laboratory of Molecular Recognition and Function
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
| | - Song Ye
- Beijing National Laboratory for Molecular Sciences
- Key Laboratory of Molecular Recognition and Function
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
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47
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Stark DG, O’Riordan TJC, Smith AD. Synthesis of Di-, Tri-, and Tetrasubstituted Pyridines from (Phenylthio)carboxylic Acids and 2-[Aryl(tosylimino)methyl]acrylates. Org Lett 2014; 16:6496-9. [DOI: 10.1021/ol503360q] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Daniel G. Stark
- EaStCHEM,
School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9ST, United Kingdom
| | - Timothy J. C. O’Riordan
- Syngenta, Jealott’s
Hill International Research Centre, Bracknell, RG42, 6EY, 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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48
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Harvey NL, Krysiak J, Chamni S, Cho SW, Sieber SA, Romo D. Synthesis of (±)-Spongiolactone Enabling Discovery of a More Potent Derivative. Chemistry 2014; 21:1425-8. [DOI: 10.1002/chem.201405980] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Indexed: 11/12/2022]
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49
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Morrill LC, Stark DG, Taylor JE, Smith SR, Squires JA, D'Hollander ACA, Simal C, Shapland P, O'Riordan TJC, Smith AD. Organocatalytic Michael addition–lactonisation of carboxylic acids using α,β-unsaturated trichloromethyl ketones as α,β-unsaturated ester equivalents. Org Biomol Chem 2014; 12:9016-27. [DOI: 10.1039/c4ob01788a] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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50
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Chen XY, Gao ZH, Song CY, Zhang CL, Wang ZX, Ye S. N-Heterocyclic Carbene Catalyzed Cyclocondensation of α,β-Unsaturated Carboxylic Acids: Enantioselective Synthesis of Pyrrolidinone and Dihydropyridinone Derivatives. Angew Chem Int Ed Engl 2014; 53:11611-5. [DOI: 10.1002/anie.201407469] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Indexed: 12/14/2022]
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