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Abstract
Nitroxides, also known as nitroxyl radicals, are long-lived or stable radicals with the general structure R1R2N-O•. The spin distribution over the nitroxide N and O atoms contributes to the thermodynamic stability of these radicals. The presence of bulky N-substituents R1 and R2 prevents nitroxide radical dimerization, ensuring their kinetic stability. Despite their reactivity toward various transient C radicals, some nitroxides can be easily stored under air at room temperature. Furthermore, nitroxides can be oxidized to oxoammonium salts (R1R2N═O+) or reduced to anions (R1R2N-O-), enabling them to act as valuable oxidants or reductants depending on their oxidation state. Therefore, they exhibit interesting reactivity across all three oxidation states. Due to these fascinating properties, nitroxides find extensive applications in diverse fields such as biochemistry, medicinal chemistry, materials science, and organic synthesis. This review focuses on the versatile applications of nitroxides in organic synthesis. For their use in other important fields, we will refer to several review articles. The introductory part provides a brief overview of the history of nitroxide chemistry. Subsequently, the key methods for preparing nitroxides are discussed, followed by an examination of their structural diversity and physical properties. The main portion of this review is dedicated to oxidation reactions, wherein parent nitroxides or their corresponding oxoammonium salts serve as active species. It will be demonstrated that various functional groups (such as alcohols, amines, enolates, and alkanes among others) can be efficiently oxidized. These oxidations can be carried out using nitroxides as catalysts in combination with various stoichiometric terminal oxidants. By reducing nitroxides to their corresponding anions, they become effective reducing reagents with intriguing applications in organic synthesis. Nitroxides possess the ability to selectively react with transient radicals, making them useful for terminating radical cascade reactions by forming alkoxyamines. Depending on their structure, alkoxyamines exhibit weak C-O bonds, allowing for the thermal generation of C radicals through reversible C-O bond cleavage. Such thermally generated C radicals can participate in various radical transformations, as discussed toward the end of this review. Furthermore, the application of this strategy in natural product synthesis will be presented.
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Affiliation(s)
- Dirk Leifert
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
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2
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Iwabuchi Y, Nagasawa S. The Utility of Oxoammonium Species in Organic Synthesis: Beyond Alcohol Oxidation. HETEROCYCLES 2022. [DOI: 10.3987/rev-21-sr(r)2] [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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Cai R, Zhou Q, Hou T, Li B, Liu Y, Li H, Gao Y, Zhu L, Luo J. Facile construction of the all-bridge-position-functionalized 2,4,6,8-tetraazaadamantane skeleton and conversion of its N-functionalities. Org Chem Front 2022. [DOI: 10.1039/d2qo00427e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An unusual protocol of a “one-pot” three-step strategy to build the 2,4,6,8-tetraazaadamantane skeleton was developed. 17 products were obtained in 19–46% yields, and the N-benzyl groups were transferred to nitroso, acetyl, benzoyl and nitro groups.
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Affiliation(s)
- Rongbin Cai
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Qi Zhou
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Tianjiao Hou
- College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Bing Li
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Yunzhi Liu
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Huan Li
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Yuan Gao
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Longyi Zhu
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Jun Luo
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
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4
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Chen F, Tang Y, Li X, Duan Y, Chen C, Zheng Y. Oxoammonium Salt‐Mediated Vicinal Oxyazidation of Alkenes with NaN
3
: Access to
β
‐Aminooxy Azides. Adv Synth Catal 2021. [DOI: 10.1002/adsc.202100783] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Fei Chen
- Henan Provincial Engineering and Technology Research Center for Precise Synthesis of Fluorine-Containing Drugs, College of Chemistry and Chemical Engineering Anyang Normal University Anyang 455000 People's Republic of China
| | - Yu‐Ting Tang
- Henan Provincial Engineering and Technology Research Center for Precise Synthesis of Fluorine-Containing Drugs, College of Chemistry and Chemical Engineering Anyang Normal University Anyang 455000 People's Republic of China
| | - Xin‐Ru Li
- Henan Provincial Engineering and Technology Research Center for Precise Synthesis of Fluorine-Containing Drugs, College of Chemistry and Chemical Engineering Anyang Normal University Anyang 455000 People's Republic of China
| | - Yan‐Yan Duan
- Henan Provincial Engineering and Technology Research Center for Precise Synthesis of Fluorine-Containing Drugs, College of Chemistry and Chemical Engineering Anyang Normal University Anyang 455000 People's Republic of China
| | - Chao‐Xing Chen
- Henan Provincial Engineering and Technology Research Center for Precise Synthesis of Fluorine-Containing Drugs, College of Chemistry and Chemical Engineering Anyang Normal University Anyang 455000 People's Republic of China
| | - Yang Zheng
- Henan Provincial Engineering and Technology Research Center for Precise Synthesis of Fluorine-Containing Drugs, College of Chemistry and Chemical Engineering Anyang Normal University Anyang 455000 People's Republic of China
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Meador RIL, Anderson RE, Chisholm JD. Tandem elimination-oxidation of tertiary benzylic alcohols with an oxoammonium salt. Org Biomol Chem 2021; 19:6233-6236. [PMID: 34231623 DOI: 10.1039/d1ob00965f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tertiary benzylic alcohols react with oxoammonium salts, undergoing a tandem elimination/allylic oxidation to provide an allylic ether product in a single step. This mode of reactivity provides a rapid entry into allylic ethers from certain benzylic tertiary alcohols. The allylic ether may be cleaved under reductive conditions to reveal the allylic alcohol.
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Affiliation(s)
- Rowan I L Meador
- Department of Chemistry, Syracuse University, 1-014 Center for Science and Technology, Syracuse, NY 13244, USA.
| | - Robert E Anderson
- Department of Chemistry, Syracuse University, 1-014 Center for Science and Technology, Syracuse, NY 13244, USA.
| | - John D Chisholm
- Department of Chemistry, Syracuse University, 1-014 Center for Science and Technology, Syracuse, NY 13244, USA.
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6
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Ruiz J, Oger P, Soulère L, Popowycz F. Straightforward Synthesis of Chiral Terpenoid Building Blocks by Ru-Catalyzed Enantioselective Hydrogenation. J Org Chem 2021; 86:9396-9406. [PMID: 34180667 DOI: 10.1021/acs.joc.1c00677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Starting from commercially available (R)- and (S)-β-citronellol, two strategies were designed to synthesize all four stereoisomers of 2,6-dimethyloctane monoterpene chirons in four or five steps in 32-47% overall yield. The desired fragments were obtained by a key Ru-catalyzed asymmetric olefin hydrogenation step under moderate temperature (50 °C), pressure (4 bar), and low catalyst loadings (0.5 mol %) under optimized conditions. Screening of commercially available catalysts highlighted the key role of DM-SEGPHOS as an economically advantageous alternative to commonly used H8-BINAP for equal performances. These results open new possibilities for versatile and scalable syntheses of these useful building blocks.
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Affiliation(s)
- Johal Ruiz
- Université de Lyon, INSA Lyon, Université Lyon 1, CNRS, CPE Lyon, UMR 5246, ICBMS, 1 rue Victor Grignard, 69621 Villeurbanne Cedex, France
| | - Philippe Oger
- Université de Lyon, INSA Lyon, CNRS, UMR 5240, 69621 Villeurbanne, France
| | - Laurent Soulère
- Université de Lyon, INSA Lyon, Université Lyon 1, CNRS, CPE Lyon, UMR 5246, ICBMS, 1 rue Victor Grignard, 69621 Villeurbanne Cedex, France
| | - Florence Popowycz
- Université de Lyon, INSA Lyon, Université Lyon 1, CNRS, CPE Lyon, UMR 5246, ICBMS, 1 rue Victor Grignard, 69621 Villeurbanne Cedex, France
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Saiter J, Guérin T, Donnard M, Panossian A, Hanquet G, Leroux FR. Direct Trifluoromethoxylation without OCF
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‐Carrier through In Situ Generation of Fluorophosgene. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100429] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jérémy Saiter
- Université de Strasbourg, Université de Haute-Alsace CNRS, UMR 7042-LIMA, ECPM 67000 Strasbourg France
| | - Thomas Guérin
- Université de Strasbourg, Université de Haute-Alsace CNRS, UMR 7042-LIMA, ECPM 67000 Strasbourg France
| | - Morgan Donnard
- Université de Strasbourg, Université de Haute-Alsace CNRS, UMR 7042-LIMA, ECPM 67000 Strasbourg France
| | - Armen Panossian
- Université de Strasbourg, Université de Haute-Alsace CNRS, UMR 7042-LIMA, ECPM 67000 Strasbourg France
| | - Gilles Hanquet
- Université de Strasbourg, Université de Haute-Alsace CNRS, UMR 7042-LIMA, ECPM 67000 Strasbourg France
| | - Frédéric R. Leroux
- Université de Strasbourg, Université de Haute-Alsace CNRS, UMR 7042-LIMA, ECPM 67000 Strasbourg France
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Beddoe RH, Andrews KG, Magné V, Cuthbertson JD, Saska J, Shannon-Little AL, Shanahan SE, Sneddon HF, Denton RM. Redox-neutral organocatalytic Mitsunobu reactions. Science 2019; 365:910-914. [DOI: 10.1126/science.aax3353] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 07/09/2019] [Indexed: 11/02/2022]
Abstract
Nucleophilic substitution reactions of alcohols are among the most fundamental and strategically important transformations in organic chemistry. For over half a century, these reactions have been achieved by using stoichiometric, and often hazardous, reagents to activate the otherwise unreactive alcohols. Here, we demonstrate that a specially designed phosphine oxide promotes nucleophilic substitution reactions of primary and secondary alcohols in a redox-neutral catalysis manifold that produces water as the sole by-product. The scope of the catalytic coupling process encompasses a range of acidic pronucleophiles that allow stereospecific construction of carbon-oxygen and carbon-nitrogen bonds.
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Liu S, Zeng X, Xu B. Ligandless Copper-Catalyzed Carboborylation of Heteroatom-Substituted Alkynes. Adv Synth Catal 2018. [DOI: 10.1002/adsc.201800656] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Shiwen Liu
- Key Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology; Donghua University; 2999 North Renmin Rd Shanghai 201620 People's Republic of China
| | - Xiaojun Zeng
- Key Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology; Donghua University; 2999 North Renmin Rd Shanghai 201620 People's Republic of China
| | - Bo Xu
- Key Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology; Donghua University; 2999 North Renmin Rd Shanghai 201620 People's Republic of China
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Kuga T, Sasano Y, Iwabuchi Y. IBX as a catalyst for dehydration of hydroperoxides: green entry to α,β-unsaturated ketones via oxygenative allylic transposition. Chem Commun (Camb) 2018; 54:798-801. [DOI: 10.1039/c7cc08957k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
A catalytic transformation of allylic hydroperoxides into α,β-unsaturated carbonyl compounds using IBX as a dehydration catalyst is described.
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Affiliation(s)
- Tetsuya Kuga
- Graduate School of Pharmaceutical Sciences
- Tohoku University
- Aoba-ku
- Japan
| | - Yusuke Sasano
- Graduate School of Pharmaceutical Sciences
- Tohoku University
- Aoba-ku
- Japan
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