1
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Eghbarieh N, Masarwa A. Desymmetrization of Diboron(4) by a Trifluorination B-Masking Strategy: Practical Synthesis of Unsymmetrical Diboron Species. J Org Chem 2024; 89:11753-11760. [PMID: 39086151 DOI: 10.1021/acs.joc.4c00715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2024]
Abstract
Herein, we report a straightforward practical and simple method for efficiently synthesizing a BF3-containing unsymmetrical diboron salt. This method involves the direct desymmetrization of commercially available diboron(4). This desymmetrization is based on a selective B-masking strategy via nucleophilic trifluorination, providing the elusive diborons bearing a trifluoroborate group. The synthetic utility of these salts is demonstrated through various examples of (sequential) B-ligand interconversions, enabling the synthesis of unsymmetrical diboron derivatives. These products, which serve as valuable building blocks, are obtained in gram-scale and high yields.
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Affiliation(s)
- Nadim Eghbarieh
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, and Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Ahmad Masarwa
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, and Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
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2
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Hanania N, Eghbarieh N, Masarwa A. PolyBorylated Alkenes as Energy-Transfer Reactive Groups: Access to Multi-Borylated Cyclobutanes Combined with Hydrogen Atom Transfer Event. Angew Chem Int Ed Engl 2024; 63:e202405898. [PMID: 38603554 DOI: 10.1002/anie.202405898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 04/11/2024] [Accepted: 04/11/2024] [Indexed: 04/13/2024]
Abstract
While polyborylated alkenes are being recognized for their elevated status as highly valuable reagents in modern organic synthesis, allowing efficient access to a diverse array of transformations, including the formation of C-C and C-heteroatom bonds, their potential as energy-transfer reactive groups has remained unexplored. Yet, this potential holds the key to generating elusive polyborylated biradical species, which can be captured by olefins, thereby leading to the construction of new highly-borylated scaffolds. Herein, we report a designed energy-transfer strategy for photosensitized [2+2]-cycloadditions of poly-borylated alkenes with various olefins enabling the regioselective synthesis of diverse poly-borylated cyclobutane motifs, including the 1,1-di-, 1,1,2-tri-, and 1,1,2,2-tetra-borylated cyclobutanes. In fact, these compounds belong to a family that presently lacks efficient synthetic pathways. Interestingly, when α-methylstyrene was used, the reaction involves an interesting 1,5-hydrogen atom transfer (HAT). Mechanistic deuterium-labeling studies have provided insight into the outcome of 1,5-hydrogen atom transfer process. In addition, the polyborylated cyclobutanes are then demonstrated to be useful in selective oxidation processes resulting in the formation of cyclobutanones and γ-lactones.
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Affiliation(s)
- Nicole Hanania
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, and Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Nadim Eghbarieh
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, and Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Ahmad Masarwa
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, and Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
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3
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Makino H, Nishikawa T, Ouchi M. Enzyme-Like Catalysis of Vinyl Copolymer Carrying Boron Directly Connected to Backbone: Catalytic Esterification through Cooperation of Boron with Neighboring Carboxylic Anhydride. Angew Chem Int Ed Engl 2024:e202410523. [PMID: 38880767 DOI: 10.1002/anie.202410523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Accepted: 06/14/2024] [Indexed: 06/18/2024]
Abstract
Alternating-rich copolymer of vinylboronic acid pinacol ester (VBpin) and maleic anhydride (MAH) was found to catalyze direct dehydrative esterification of carboxylic acid and alcohol. The key to the catalytic function is the activation of the MAH unit by the neighboring Lewis acidic boron directly connected to the backbone through the formation of five-membered ring. The effects of the side-chain cooperation were clarified through comparisons with the polymers having similar structures and a conventional titanium catalyst as well as the analyses of reactions with carboxylic acid or alcohol. The catalytic activity was enhanced as the molecular weight was higher, which is owing to the structural feature that boron is directly attached to the backbone. The cooperative catalysis is of interest because of its conceptual similarity with enzyme.
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Affiliation(s)
- Hiroshi Makino
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura, Nishikyo-ku, Kyoto, Kyoto, 615-8510, Japan
| | - Tsuyoshi Nishikawa
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura, Nishikyo-ku, Kyoto, Kyoto, 615-8510, Japan
| | - Makoto Ouchi
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura, Nishikyo-ku, Kyoto, Kyoto, 615-8510, Japan
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4
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Shi Y, Xu S, Zhao J, Zhu H, Pan X, Zhao B, Sun Z, Li N, Hou X. Development of injectable in situ hydrogels based on hyaluronic acid via Diels-Alder reaction for their antitumor activities studies. Int J Biol Macromol 2024; 262:129642. [PMID: 38266838 DOI: 10.1016/j.ijbiomac.2024.129642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 01/09/2024] [Accepted: 01/18/2024] [Indexed: 01/26/2024]
Abstract
The objective of this study was to develop an injectable hydrogel based on furfuryl amine-conjugated hyaluronic acid (FA-conj-HA) and evaluate the in vivo anti-4 T1 tumor activity of doxorubicin-loaded hydrogel (DOX@FA-conj-HAgel). The cargo-free hydrogel (FA-conj-HAgel) was fabricated through a Diels-Alder reaction at 37 °C with FA-conj-HA as a gel material and four armed poly(ethylene glycol)2000-maleimide (4-arm-PEG2000-Mal) as a cross-linker. The bio-safety of FA-conj-HAgel were assessed, and the in vivo antitumor activity of DOX@FA-conj-HAgel was also investigated. Many 3D network structures were observed from scanning electron microscope (SEM) photograph, confirming the successful preparation of FA-conj-HAgel. The absence of cytotoxicity from FA-conj-HAgel was proved by the high viability of 4 T1 cells. In vivo bio-safety studies suggested that the obtained FA-conj-HAgel did not induce acute toxicity or other lesions in treated mice, confirming its high bio-safety. The reduced tumor volumes, hematoxylin-eosin staining (H&E), and TdT-mediated dUTP-biotin nick end labeling (TUNEL) analysis indicated the potent in vivo anti-4 T1 tumor effects of DOX@FA-conj-HAgel. In conclusion, the favorable bio-safety and potent antitumor activity of DOX@FA-conj-HAgel highlighted its potential application in oncological therapy.
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Affiliation(s)
- Yongli Shi
- College of pharmacy, Xinxiang Medical University, 453003 Xinxiang, PR China.
| | - Suyue Xu
- College of pharmacy, Xinxiang Medical University, 453003 Xinxiang, PR China
| | - Jingya Zhao
- College of pharmacy, Xinxiang Medical University, 453003 Xinxiang, PR China
| | - Huiqing Zhu
- College of pharmacy, Xinxiang Medical University, 453003 Xinxiang, PR China
| | - Xiaofei Pan
- College of pharmacy, Xinxiang Medical University, 453003 Xinxiang, PR China
| | - Bingqian Zhao
- Basic Medicine College, Xinxiang Medical University, 453003, Xinxiang, PR China
| | - Zeyu Sun
- First Clinical College, Xinxiang Medical University, 453003 Xinxiang, PR China
| | - Na Li
- College of pharmacy, Xinxiang Medical University, 453003 Xinxiang, PR China.
| | - Xueyan Hou
- College of pharmacy, Xinxiang Medical University, 453003 Xinxiang, PR China; Pingyuan Laboratory, Xinxiang, Henan 453007, PR China.
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5
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Ahmed EAMA, Zhang H, Cao WG, Gong TJ. Palladium-Catalyzed Cross-Coupling of gem-Difluorocyclopropanes with gem-Diborylalkanes for the Synthesis of Boryl-Substituted Fluorinated Alkenes. Org Lett 2023; 25:9020-9024. [PMID: 38063840 DOI: 10.1021/acs.orglett.3c03626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
This study presents a novel method for the regioselective coupling of gem-difluorinated cyclopropanes with gem-diborylmethane, utilizing a Pd-catalyst system. This innovative approach enables the synthesis of 2-fluoroalkenyl monoboronate scaffolds with high Z-selectivity. The resulting products undergo further transformations, including oxidation, Suzuki cross-coupling, and trifluoroborylation, all of which are achieved with good yields. This work introduces a valuable synthetic pathway to access important fluorinated compounds for various applications in organic chemistry.
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Affiliation(s)
| | - Hongchen Zhang
- College of pharmacy, Wenzhou Medical University, Wenzhou 325035, China
| | - Wen-Gen Cao
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China
| | - Tian-Jun Gong
- Hefei National Research Center for Physical Sciences at the Microscale, iChEM, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy University of Science and Technology of China, Hefei 230026, People's Republic of China
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6
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Vidal F, Smith S, Williams CK. Ring Opening Copolymerization of Boron-Containing Anhydride with Epoxides as a Controlled Platform to Functional Polyesters. J Am Chem Soc 2023. [PMID: 37311063 DOI: 10.1021/jacs.3c03261] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Boron-functionalized polymers are used in opto-electronics, biology, and medicine. Methods to produce boron-functionalized and degradable polyesters remain exceedingly rare but relevant where (bio)dissipation is required, for example, in self-assembled nanostructures, dynamic polymer networks, and bio-imaging. Here, a boronic ester-phthalic anhydride and various epoxides (cyclohexene oxide, vinyl-cyclohexene oxide, propene oxide, allyl glycidyl ether) undergo controlled ring-opening copolymerization (ROCOP), catalyzed by organometallic complexes [Zn(II)Mg(II) or Al(III)K(I)] or a phosphazene organobase. The polymerizations are well controlled allowing for the modulation of the polyester structures (e.g., by epoxide selection, AB, or ABA blocks), molar masses (9.4 < Mn < 40 kg/mol), and uptake of boron functionalities (esters, acids, "ates", boroxines, and fluorescent groups) in the polymer. The boronic ester-functionalized polymers are amorphous, with high glass transition temperatures (81 < Tg < 224 °C) and good thermal stability (285 < Td < 322 °C). The boronic ester-polyesters are deprotected to yield boronic acid- and borate-polyesters; the ionic polymers are water soluble and degradable under alkaline conditions. Using a hydrophilic macro-initiator in alternating epoxide/anhydride ROCOP, and lactone ring opening polymerization, produces amphiphilic AB and ABC copolyesters. Alternatively, the boron-functionalities are subjected to Pd(II)-catalyzed cross-couplings to install fluorescent groups (BODIPY). The utility of this new monomer as a platform to construct specialized polyesters materials is exemplified here in the synthesis of fluorescent spherical nanoparticles that self-assemble in water (Dh = 40 nm). The selective copolymerization, variable structural composition, and adjustable boron loading represent a versatile technology for future explorations of degradable, well-defined, and functional polymers.
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Affiliation(s)
- Fernando Vidal
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Sevven Smith
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Charlotte K Williams
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
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7
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Allen MA, Volosheniuk M, Nicol EA, Schwan AL, Beauchemin AM. Cope-Type Hydroamination of Vinylboronates. Org Lett 2023; 25:3045-3048. [PMID: 37097727 DOI: 10.1021/acs.orglett.3c00857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
Aminoboronic acid derivatives can serve as versatile synthetic intermediates and pharmacophores but remain difficult to synthesize. Herein we report a synthesis of the β-aminoboronic acid motif via anti-Markovnikov hydroamination of vinylboronates. This reaction benefits from the activating effect of the boronate substituent and forms novel BON-containing heterocycles, oxazaborolidine zwitterions. A computational study is included to help determine the effects of alkene boron substitution. Derivatization reactions also support the synthetic utility of the oxazaborolidine adducts.
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Affiliation(s)
- Meredith A Allen
- Centre for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Myroslava Volosheniuk
- Centre for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Eric A Nicol
- Department of Chemistry, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Adrian L Schwan
- Department of Chemistry, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - André M Beauchemin
- Centre for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
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8
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Eghbarieh N, Hanania N, Masarwa A. Stereodefined polymetalloid alkenes synthesis via stereoselective boron-masking of polyborylated alkenes. Nat Commun 2023; 14:2022. [PMID: 37041219 PMCID: PMC10090189 DOI: 10.1038/s41467-023-37733-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 03/28/2023] [Indexed: 04/13/2023] Open
Abstract
Polyborylated-alkenes are valuable polymetalloid reagents in modern organic synthesis, providing access to a wide array of transformations, including the construction of multiple C-C and C-heteroatom bonds. However, because they contain similar boryl groups, many times their transformation faces the main challenge in controlling the chemo-, regio- and stereoselectivity. One way to overcome these limitations is by installing different boron groups that can provide an opportunity to tune their reactivity toward better chemo-, regio- and stereoselectivity. Yet, the preparation of polyborylated-alkenes containing different boryl groups has been rare. Herein we report concise, highly site-selective, and stereoselective boron-masking strategies of polyborylated alkenes. This is achieved by designed stereoselective trifluorination and MIDA-ation reactions of readily available starting polyborylated alkenes. Additionally, the trifluoroborylated-alkenes undergo a stereospecific interconversion to Bdan-alkenes. These transition-metal free reactions provide a general and efficient method for the conversion of polyborylated alkenes to access 1,1-di-, 1,2-di-, 1,1,2-tris-(borylated) alkenes containing BF3M, Bdan, and BMIDA, a family of compounds that currently lack efficient synthetic access. Moreover, tetraborylethene undergoes the metal-free MIDA-ation reaction to provide the mono BMIDA tetraboryl alkene selectively. The mixed polyborylalkenes are then demonstrated to be useful in selective C-C and C-heteroatom bond-forming reactions. Given its simplicity and versatility, these stereoselective boron-masking approaches hold great promise for organoboron synthesis and will result in more transformations.
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Affiliation(s)
- Nadim Eghbarieh
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Nicole Hanania
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Ahmad Masarwa
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel.
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9
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Nagaraju A, Saiaede T, Eghbarieh N, Masarwa A. Photoredox-Mediated Deoxygenative Radical Additions of Aromatic Acids to Vinyl Boronic Esters and gem-Diborylalkenes. Chemistry 2023; 29:e202202646. [PMID: 36222076 PMCID: PMC10100356 DOI: 10.1002/chem.202202646] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Indexed: 11/27/2022]
Abstract
A new method to access β-keto-gem-diborylalkanes, by direct deoxygenative radical addition of aromatic carboxylic acids to gem-dibortlalkenes, is described. The reaction proceeds under mild photoredox catalysis and involves the photochemical C-O bond activation of aromatic carboxylic acids in the presence of PPh3 . It generates an acyl radical, which further undergoes an additional reaction with gem-diborylalkenes to form an α-gem-diboryl alkyl radical intermediate, which then reduces to the corresponding anion, which after protonation, affords the β-keto-gem-diborylalkane product. Moreover, the same scenario has been extended to the vinyl boronic esters, for example, gem-(Ar, Bpin)-alkenes, and gem-(Alkyl, Bpin)-alkenes. Importantly, this protocol provides a general platform for the late-stage functionalization of bio-active and drug molecules containing a carboxylic acid group.
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Affiliation(s)
- Anugula Nagaraju
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel
| | - Tamer Saiaede
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel
| | - Nadim Eghbarieh
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel
| | - Ahmad Masarwa
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel
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10
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Stephens SM, Bray JM, Weierbach SM, Adornato GM, Schrider JA, Lambert KM. Facile access to 1,3-bis(boryl) dienes to build molecular complexity through cycloadditions. Tetrahedron Lett 2023. [DOI: 10.1016/j.tetlet.2023.154381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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11
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Hanania N, Nassir M, Eghbarieh N, Masarwa A. A Stereodivergent Approach to the Synthesis of gem-Diborylcyclopropanes. Chemistry 2022; 28:e202202748. [PMID: 36161797 PMCID: PMC10092851 DOI: 10.1002/chem.202202748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Indexed: 12/30/2022]
Abstract
We report a designed stereodivergent strategy for the synthesis of gem-diborylcyclopropanes. The reaction provides a highly modular approach to prepare cyclopropane ring variants bearing gem-(Bpin,Bpin), gem-(Bpin,Bdan), and gem-(Bpin,BF3 K), with outstanding levels of stereocontrol. This was achieved by diastereoselective Pd-catalyzed cyclopropanation reactions of gem-diborylalkenes with α-diazoarylacetates and α-diazoaryl-trifluoromethyl. The key to the success of this general protocol was the diastereoselective trifluorination reaction of gem-diborylcyclopropanes, followed by the stereospecific interconversion of the trifluoroborate salts into the Bdan group.
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Affiliation(s)
- Nicole Hanania
- Institute of Chemistry, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Molhm Nassir
- Institute of Chemistry, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Nadim Eghbarieh
- Institute of Chemistry, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Ahmad Masarwa
- Institute of Chemistry, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
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12
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Kanazawa T, Nishikawa T, Ouchi M. Orthogonal C-B Bond Transformation as an Approach for Versatile Synthesis of End-Functionalized Polymers. ACS Macro Lett 2022; 11:706-710. [PMID: 35570803 DOI: 10.1021/acsmacrolett.2c00207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Conventionally inaccessible end-functionalized vinyl polymers were synthesized via orthogonal side-chain replacement for terminal and repeating units of poly(alkenyl boronate)s. A terminal-defined polymer of isopropenyl boronic acid pinacol ester (IPBpin) was synthesized via RAFT polymerization, and subsequent cobalt (Co)-catalyzed end olefination afforded the polymer carrying the C(sp2)-B bond at the terminal and the C(sp3)-B bond in repeating units. Herein, the terminal C(sp2)-B bond was selectively transformable via palladium (Pd)-catalyzed Suzuki-Miyaura cross coupling, and subsequent transformation of the repeating C(sp3)-B unit gave the poly(α-methyl vinyl alcohol) [poly(MVA)] bearing various functional groups at the terminal. The boron-based stepwise polymer reaction thus overcame the synthetic difficulty of the end-functionalized poly(MVA), which is ascribed to the poor polymerization ability of the corresponding acetate monomer, i.e., isopropenyl acetate.
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Affiliation(s)
- Tomoaki Kanazawa
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Tsuyoshi Nishikawa
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Makoto Ouchi
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
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13
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14
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Zeng Y, Zhou Y, Quan Q, Chen M. Facile Access to gem-Trifluoromethyl/Boron-Functionalized Polymers via Free-Radical Copolymerization and Cotelomerization. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00023] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Yang Zeng
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Yang Zhou
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Qinzhi Quan
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Mao Chen
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
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15
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Paul S, Das KK, Aich D, Manna S, Panda S. Recent developments in the asymmetric synthesis and functionalization of symmetrical and unsymmetrical gem-diborylalkanes. Org Chem Front 2022. [DOI: 10.1039/d1qo01300a] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
gem-Diborylalkanes are an important class of organoboron compounds as they function as a key building block in organic synthesis. This review summarizes recent developments of the enantioselective synthesis of gem-diborylalkanes and application in asymmetric synthesis.
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Affiliation(s)
- Swagata Paul
- Department of Chemistry, Indian Institute of Technology, Kharagpur, 721302, India
| | - Kanak Kanti Das
- Department of Chemistry, Indian Institute of Technology, Kharagpur, 721302, India
| | - Debasis Aich
- Department of Chemistry, Indian Institute of Technology, Kharagpur, 721302, India
| | - Samir Manna
- Department of Chemistry, Indian Institute of Technology, Kharagpur, 721302, India
| | - Santanu Panda
- Department of Chemistry, Indian Institute of Technology, Kharagpur, 721302, India
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16
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Lee Y, Han S, Cho SH. Catalytic Chemo- and Enantioselective Transformations of gem-Diborylalkanes and (Diborylmethyl)metallic Species. Acc Chem Res 2021; 54:3917-3929. [PMID: 34612034 DOI: 10.1021/acs.accounts.1c00455] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Chemo- and stereoselective transformations of polyborylalkanes are powerful and efficient methods to access optically active molecules with greater complexity and diversity through programmed synthetic design. Among the various polyborylalkanes, gem-diborylalkanes have attracted much attention in organic chemistry as versatile synthetic handles. The notable advantage of gem-diborylalkanes lies in their ability to generate two key intermediates, α-borylalkyl anions and (gem-diborylalkyl) anions. These two different intermediates can be applied to various enantioselective reactions to rapidly access a diverse set of enantioenriched organoboron compounds, which can be further manipulated to generate various chiral molecule libraries via stereospecific C(sp3)-B bond transformations.In this Account, we summarize our recent contributions to the development of catalytic chemo- and stereoselective reactions using gem-diborylalkanes as versatile nucleophiles, which can be categorized as follows: (1) copper-catalyzed enantioselective coupling of gem-diborylalkanes with electrophiles and (2) the design and synthesis of (diborylmethyl)metallic species and their applications to enantioselective reactions. Since Shibata and Endo reported the Pd-catalyzed chemoselective Suzuki-Miyaura cross-coupling of gem-diborylalkanes with organohalides in 2014, Morken and Hall subsequently developed the first enantioselective analogous reactions using TADDOL-derived chiral phosphoramidite as the supporting ligand of a palladium catalyst. This discovery sparked interest in the catalytic enantioselective coupling of gem-diborylalkanes with electrophiles. Our initial studies focused on generating chiral (α-borylmethyl)copper species by enantiotopic-group-selective transmetalation of gem-diborylalkanes with chiral copper complexes and their reactions with various aldimines and ketimines to afford syn-β-aminoboronate esters with excellent enantio- and diastereoselectivity. Moreover, we developed the enantioselective allylation of gem-diborylalkanes that proceeded by reaction of in situ-generated chiral (α-borylalkyl)copper and allyl bromides. Mechanistic investigations revealed that the enantiotopic-group-selective transmetalation between gem-diborylalkanes and the chiral copper complex occurred through the open transition state rather than the closed transition state, thereby effectively generating chiral (α-borylmethyl)copper species. We also utilized (diborylmethyl)metallic species such as (diborylmethyl)silanes and (diborylmethyl)zinc halides in catalytic enantioselective reactions. We succeeded in developing the enantiotopic-group-selective cross-coupling of (diborylmethyl)silanes with aryl iodides to afford enantioenriched benzylic 1,1-silylboronate esters, which could be used for further consecutive stereospecific transformations to afford various enantioenriched molecules. In addition, we synthesized (diborylmethyl)zinc halides for the first time by the transmetalation of isolated (diborylmethyl)lithium and zinc(II) halides and their utilization to the synthesis of enantioenriched gem-diborylalkanes bearing a chiral center at the β-position via an iridium-catalyzed enantioselective allylic substitution process. In addition to our research efforts, we also include key contributions by other research groups. We hope that this Account will draw the attention of the synthetic community to gem-diboryl compounds and provide guiding principles for the future development of catalytic enantioselective reactions using gem-diboryl compounds.
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Affiliation(s)
- Yeosan Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Seungcheol Han
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Seung Hwan Cho
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
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Affiliation(s)
- Brian P. Jacobs
- Department of Chemistry, University of Tennessee—Knoxville, Knoxville, Tennessee 37996, United States
| | - Johnathan N. Brantley
- Department of Chemistry, University of Tennessee—Knoxville, Knoxville, Tennessee 37996, United States
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Labadie N, Ramos Marchena JM, Medrán NS, Pellegrinet SC. Allenylboronic Acid Pinacol Ester: A Selective Partner for [4 + 2] Cycloadditions. Org Lett 2021; 23:5081-5085. [PMID: 34151574 DOI: 10.1021/acs.orglett.1c01609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have studied the reaction of allenylboronic acid pinacol ester with cyclopentadiene with experimental and computational methods. The reaction occurred efficiently with complete Diels-Alder periselectivity and regioselectivity at the proximal double bond. The concerted mechanism for the observed transformation was computed to be favored over competitive addition to the distal double bond, [3,3]-sigmatropic rearrangements, and stepwise radical mechanism. This unprecedented Diels-Alder reaction enables the construction of synthetically versatile boron-substituted cycloadducts.
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Affiliation(s)
- Natalia Labadie
- Instituto de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario 2000, Argentina
| | - Juan M Ramos Marchena
- Instituto de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario 2000, Argentina
| | - Noelia S Medrán
- Instituto de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario 2000, Argentina
| | - Silvina C Pellegrinet
- Instituto de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario 2000, Argentina
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