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Benz S, Murkin AS. α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions. Beilstein J Org Chem 2021; 17:2570-2584. [PMID: 34760025 PMCID: PMC8551875 DOI: 10.3762/bjoc.17.172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/07/2021] [Indexed: 11/24/2022] Open
Abstract
In the presence of a suitable acid or base, α-hydroxyaldehydes, ketones, and imines can undergo isomerization that features the 1,2-shift of an alkyl or aryl group. In the process, the hydroxy group is converted to a carbonyl and the aldehyde/ketone or imine is converted to an alcohol or amine. Such α-ketol/α-iminol rearrangements are used in a wide variety of synthetic applications including asymmetric synthesis, tandem reactions, and the total synthesis and biosynthesis of natural products. This review explores the use of α-ketol rearrangements in these contexts over the past two decades.
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Affiliation(s)
- Scott Benz
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Andrew S Murkin
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
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2
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Takasu K, Shigenaga K, Shimoda K, Takikawa H, Yamaoka Y. Synthesis of Lactone-Fused Cyclopropanes by Ring Contractive α-Ketol Rearrangement of Ketal-Fused Cyclobutanones. HETEROCYCLES 2021. [DOI: 10.3987/com-20-s(k)6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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3
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Nandi RP, Sudhakar P, Kalluvettukuzhy NK, Thilagar P. Triarylborane-Appended Anils and Boranils: Solid-State Emission, Mechanofluorochromism, and Phosphorescence. Chemistry 2020; 26:16306-16317. [PMID: 32578898 DOI: 10.1002/chem.202001470] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/24/2020] [Indexed: 01/08/2023]
Abstract
Herein, the design, synthesis, optical properties, and mechanofluorochromism characteristics of a series of conjugates having covalently linked triarylborane (TAB) and anil/boranil units (TAB-anil: 1 a-3 a and TAB-boranil: 1-3) are reported. The electronic interactions between TAB and anil/boranil in 1 a-3 a and 1-3 were fine-tuned by changing the boryl moiety's position on the phenyl spacer connecting the BMes2 (Mes=mesityl) and anil/boranil units. A boryl moiety at the meta position (1 a) of the phenyl spacer stabilizes the enolic form (E-OH), whereas a boryl moiety at the para position (2 a and 3 a) stabilizes the keto form (Z-NH) in the solid state. However, in solution 1 a, 2 a, and 3 a exhibit keto-enol tautomerism in both ground and excited states. Compounds 1 a-3 a and 1-3 show red-shifted absorption compared with 4 a and 4, which are devoid of TAB moieties, which indicate effective participation of an empty p orbital on the boron center in 1 a-3 a and 1-3. Compounds 1 and 2 showed fluorescence variations in response to external stimuli such as mechanical grinding. Long phosphorescence lifetimes of 18-46 ms were observed for compounds 1-3. The observed optical properties of 1 a-3 a and 1-3 are rationalized in the context of quantum mechanical calculations.
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Affiliation(s)
- Rajendra Prasad Nandi
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Pagidi Sudhakar
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Neena K Kalluvettukuzhy
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Pakkirisamy Thilagar
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India
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4
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Krasavin M, Chuprun S, Dar’in D, Kantin G, Zhmurov P. α-Diazoacetamides in Sc(OTf)3-Catalyzed Tiffeneau–Demjanov Ring Expansion: Application towards the Synthesis of Rare Bicyclic Pyrazoles. Synlett 2020. [DOI: 10.1055/s-0039-1690047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A novel Sc(OTf)3-catalyzed Tiffeneau–Demjanov ring expansion of six-membered cyclic ketones has been developed. The resulting seven-membered cyclic β-keto carboxamides were found to be versatile precursors to rare bicyclic pyrazoles obtained in modest to good yields via condensation with aryl hydrazines in the presence of Lawesson’s reagent.
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Moore LC, Lo A, Fell JS, Duong MR, Moreno JA, Rich BE, Bravo M, Fettinger JC, Souza LW, Olmstead MM, Houk KN, Shaw JT. Acyclic Stereocontrol in the Additions of Nucleophilic Alkenes to α‐Chiral
N
‐Sulfonyl Imines. Chemistry 2019; 25:12214-12220. [DOI: 10.1002/chem.201902790] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Indexed: 12/15/2022]
Affiliation(s)
- Lucas C. Moore
- Department of Chemistry and Biochemistry University of California One Shields Ave. Davis CA 95616 USA
| | - Anna Lo
- Department of Chemistry and Biochemistry University of California One Shields Ave. Davis CA 95616 USA
| | - Jason S. Fell
- Department of Chemistry University of California, Los Angeles 607 Charles E. Young Drive East Los Angeles CA 90095-1569 USA
| | - Matthew R. Duong
- Department of Chemistry and Biochemistry University of California One Shields Ave. Davis CA 95616 USA
| | - Jose A. Moreno
- Department of Chemistry and Biochemistry University of California One Shields Ave. Davis CA 95616 USA
| | - Barry E. Rich
- Department of Chemistry and Biochemistry University of California One Shields Ave. Davis CA 95616 USA
| | - Martin Bravo
- Department of Chemistry and Biochemistry University of California One Shields Ave. Davis CA 95616 USA
| | - James C. Fettinger
- Department of Chemistry and Biochemistry University of California One Shields Ave. Davis CA 95616 USA
| | - Lucas W. Souza
- Department of Chemistry and Biochemistry University of California One Shields Ave. Davis CA 95616 USA
| | - Marilyn M. Olmstead
- Department of Chemistry and Biochemistry University of California One Shields Ave. Davis CA 95616 USA
| | - Kendall N. Houk
- Department of Chemistry University of California, Los Angeles 607 Charles E. Young Drive East Los Angeles CA 90095-1569 USA
| | - Jared T. Shaw
- Department of Chemistry and Biochemistry University of California One Shields Ave. Davis CA 95616 USA
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Lugovik KI, Eltyshev AK, Suntsova PO, Smoluk LT, Belousova AV, Ulitko MV, Minin AS, Slepukhin PA, Benassi E, Belskaya NP. Fluorescent boron complexes based on new N,O-chelates as promising candidates for flow cytometry. Org Biomol Chem 2019; 16:5150-5162. [PMID: 29963677 DOI: 10.1039/c8ob00868j] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This study presents the synthesis and optical properties of a new class of bright green-yellow fluorescent dyes with potential applications in bioimaging. A facile synthetic route via the chelation of aryl(hetaryl)aminoacryloylthiophene scaffolds with a BF2 fragment is presented. The photophysical properties of the dyes are attributed to the nature and position of electron-donating and electron-withdrawing substituents. Upon coordination to a BF2 fragment, characteristic emission was observed, with λem ranging from 503 to 543 nm and quantum yields of 0.14-0.42. Compared with parent aryl(hetaryl)aminoacryloylthiophenes, a significant red shift in absorption (up to 480 nm in solution) and emission (up to 543 nm in solution and 610 nm in the solid state) and high chemical stability and photostability were observed. The electron-accepting character of the substituents on the terminal aromatic ring or replacing this fragment with pyridine or pyrazine moieties resulted in increased quantum yields. To gain insight into the electronic structures and optical properties, quantum mechanical calculations were performed. The results of (TD-)DFT calculations supported the structural and spectroscopic data and showed the features of electronic distribution in the frontier molecular orbitals and active electrophilic and nucleophilic sites in the compounds investigated. Synthesized BF2 complexes are promising dyes for cell imaging and flow cytometry owing to their ready penetration and accumulation in cells.
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Affiliation(s)
- Kseniya I Lugovik
- Ural Federal University, 19 Mira Str., Yekaterinburg, 620002, Russian Federation.
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Yu Y, Sha Q, Cui H, Chandler KS, Doyle MP. Displacement of Dinitrogen by Oxygen: A Methodology for the Catalytic Conversion of Diazocarbonyl Compounds to Ketocarbonyl Compounds by 2,6-Dichloropyridine-N-oxide. Org Lett 2018; 20:776-779. [DOI: 10.1021/acs.orglett.7b03912] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yang Yu
- Department
of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Qiang Sha
- Department
of Chemistry, College of Sciences, Nanjing Agricultural University, Nanjing, China 210095
| | - Hui Cui
- Department
of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Kory S. Chandler
- Department
of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Michael P. Doyle
- Department
of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
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8
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Wei Y, Xuan Q, Zhou Y, Song Q. Reductive N-alkylation of primary and secondary amines using carboxylic acids and borazane under mild conditions. Org Chem Front 2018. [DOI: 10.1039/c8qo00942b] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An expedient strategy of reductive N-alkylation of amines with readily available carboxylic acids as alkylating reagents has been developed.
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Affiliation(s)
- Yahui Wei
- Institute of Next Generation Matter Transformation
- College of Chemical Engineering at Huaqiao University
- Xiamen
- P. R. China
| | - Qingqing Xuan
- Institute of Next Generation Matter Transformation
- College of Chemical Engineering at Huaqiao University
- Xiamen
- P. R. China
| | - Yao Zhou
- Institute of Next Generation Matter Transformation
- College of Chemical Engineering at Huaqiao University
- Xiamen
- P. R. China
| | - Qiuling Song
- Institute of Next Generation Matter Transformation
- College of Chemical Engineering at Huaqiao University
- Xiamen
- P. R. China
- College of Pharmaceutical Sciences
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Kuznetsov DM, Kutateladze AG. Step-Economical Photoassisted Diversity-Oriented Synthesis: Sustaining Cascade Photoreactions in Oxalyl Anilides to Access Complex Polyheterocyclic Molecular Architectures. J Am Chem Soc 2017; 139:16584-16590. [PMID: 29053265 DOI: 10.1021/jacs.7b07598] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Atom- and step-economy in photoassisted diversity-oriented synthesis (DOS) is achieved with a versatile oxalyl linker offering rapid access to complex alkaloid mimics in very few experimentally simple steps: (i) it allows for fast tethering of the photoactive core to the unsaturated pendants, especially important in the case of (hetero)aromatic amines-essentially a one-pot reaction with no isolation of intermediates; (ii) the α-dicarbonyl tether acts as a chromophore enhancer, extending the conjugation chain and facilitating the "harvest" of the lower energy photons for the primary and secondary photoreactions; (iii) it enhances the quantum yield of intersystem crossing (ISC), i.e., it is capable of sensitizing secondary photochemical processes in the cascade; and (iv) the tether forms an additional heterocyclic moiety, imidazolidine-4,5-dione, a known pharmacophore. The overall photoassisted cascade is an efficient complexity-building process as quantified by computed step-normalized complexity indices, leading to extended polyheterocyclic molecular architectures comparable in complexity to natural products such as paclitaxel while requiring only 2-4 simple synthetic steps from readily available chemical feedstock.
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Affiliation(s)
- Dmitry M Kuznetsov
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208, United States
| | - Andrei G Kutateladze
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208, United States
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Liu Y, Zhang Z, Wan Y, Zhang G, Li Z, Bi J, Ma N, Liu T, Liu Q. Oxidation of β-Ketoamides: The Synthesis of Vicinal Tricarbonyl Amides. J Org Chem 2017; 82:3901-3907. [PMID: 28230362 DOI: 10.1021/acs.joc.6b03062] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A facile and direct oxidative reaction for the synthesis of vicinal tricarbonyl amides in moderate to excellent yields (53-88%) was developed starting from readily available β-ketoamides in the presence of phenyliodine(III) bis(trifluoroacetate). The resulting products possess significant synthetic potential, making this approach a valuable addition to the group of traditional methods already available for the preparation of these molecules.
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Affiliation(s)
- Yueyang Liu
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henna Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University , Xinxiang, Henan 453007, P. R. China
| | - Zhiguo Zhang
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henna Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University , Xinxiang, Henan 453007, P. R. China
| | - Yameng Wan
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henna Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University , Xinxiang, Henan 453007, P. R. China
| | - Guisheng Zhang
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henna Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University , Xinxiang, Henan 453007, P. R. China
| | - Zhonglian Li
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henna Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University , Xinxiang, Henan 453007, P. R. China
| | - Jingjing Bi
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henna Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University , Xinxiang, Henan 453007, P. R. China
| | - Nana Ma
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henna Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University , Xinxiang, Henan 453007, P. R. China
| | - Tongxin Liu
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henna Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University , Xinxiang, Henan 453007, P. R. China
| | - Qingfeng Liu
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henna Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University , Xinxiang, Henan 453007, P. R. China
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Xu C, Xu J. An expeditious method to synthesize difluoroboron complexes of β-keto amides from β-keto nitriles and BF3·OEt2. Org Biomol Chem 2017; 15:6375-6383. [DOI: 10.1039/c7ob01356f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
An expeditious and convenient method has been developed to synthesize difluoroboron complexes of β-keto amides from β-keto nitriles and BF3·OEt2.
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Affiliation(s)
- Chuangchuang Xu
- State Key Laboratory of Chemical Resource Engineering
- Department of Organic Chemistry
- Faculty of Science
- Beijing University of Chemical Technology
- Beijing 100029
| | - Jiaxi Xu
- State Key Laboratory of Chemical Resource Engineering
- Department of Organic Chemistry
- Faculty of Science
- Beijing University of Chemical Technology
- Beijing 100029
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