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Zhao Q, Li B, Zhou X, Wang Z, Zhang FL, Li Y, Zhou X, Fu Y, Wang YF. Boryl Radicals Enabled a Three-Step Sequence to Assemble All-Carbon Quaternary Centers from Activated Trichloromethyl Groups. J Am Chem Soc 2022; 144:15275-15285. [PMID: 35950969 DOI: 10.1021/jacs.2c05798] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The construction of diversely substituted all-carbon quaternary centers has been a longstanding challenge in organic synthesis. Methods that add three alkyl substituents to a simple C(sp3) atom rely heavily on lengthy multiple processes, which usually involve several preactivation steps. Here, we describe a straightforward three-step sequence that uses a range of readily accessible activated trichloromethyl groups as the carbon source, the three C-Cl bonds of which are selectively functionalized to introduce three alkyl chains. In each step, only a single C-Cl bond was cleaved with the choice of an appropriate Lewis base-boryl radical as the promoter. A vast range of diversely substituted all-carbon quaternary centers could be accessed directly from these activated CCl3 trichloromethyl groups or by simple derivatizations. The use of different alkene traps in each of the three steps enabled facile collections of a large library of products. The utility of this strategy was demonstrated by the synthesis of variants of two drug molecules, whose structures could be easily modulated by varying the alkene partner in each step. The results of kinetic and computational studies enabled the design of the three-step reaction and provided insights into the reaction mechanisms.
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Affiliation(s)
- Qiang Zhao
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Bin Li
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Xi Zhou
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Zhao Wang
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Feng-Lian Zhang
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Yuanming Li
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Xiaoguo Zhou
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Yao Fu
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Yi-Feng Wang
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, Hefei 230026, Anhui, China.,State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
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Peng TY, Xu ZY, Zhang FL, Li B, Xu WP, Fu Y, Wang YF. Dehydroxylative Alkylation of α-Hydroxy Carboxylic Acid Derivatives via a Spin-Center Shift. Angew Chem Int Ed Engl 2022; 61:e202201329. [PMID: 35388555 DOI: 10.1002/anie.202201329] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Indexed: 11/05/2022]
Abstract
A strategically distinct dehydroxylative alkylation reaction of α-hydroxy carboxylic acid derivatives with alkenes is developed. The reaction starts with the attack of a 4-dimethylaminopyridine (DMAP)-boryl radical to the carbonyl oxygen atom, followed by a spin-center shift (SCS) to trigger the C-O bond scission. The resulting α-carbonyl radicals couple with a wide range of alkenes to furnish various alkylated products. This strategy allows for the efficient conversion of a wide array of α-hydroxy amides and esters derived from several biomass molecules and natural products to value-added compounds. Experimental and computational studies verified the reaction mechanism.
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Affiliation(s)
- Tian-Yu Peng
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Zhe-Yuan Xu
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Feng-Lian Zhang
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Bin Li
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Wen-Ping Xu
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Yao Fu
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China
| | - Yi-Feng Wang
- CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, China.,State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China
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3
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Volodarsky S, Malahov I, Bawari D, Diab M, Malik N, Tumanskii B, Dobrovetsky R. Geometrically constrained square pyramidal phosphoranide. Chem Sci 2022; 13:5957-5963. [PMID: 35685804 PMCID: PMC9132080 DOI: 10.1039/d2sc01060g] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/27/2022] [Indexed: 02/03/2023] Open
Abstract
Geometrical constriction of main group elements leading to a change in the reactivity of these main group centers has recently become an important tool in main group chemistry. A lot of focus on using this modern method is dedicated to group 15 elements and especially to phosphorus. In this work, we present the synthesis, isolation and preliminary reactivity study of the geometrically constrained, square pyramidal (SP) phosphoranide anion (1-). Unlike, trigonal bipyramidal (TBP) phosphoranides that were shown to react as nucleophiles while their redox chemistry was not reported, 1- reacts both as a nucleophile and reductant. The chemical oxidation of 1- leads to a P-P dimer (1-1) that is formed via the dimerization of unstable SP phosphoranyl radical (1˙), an unprecedented decay pathway for phosphoranyl radicals. Reaction of 1- with benzophenone leads via a single electron transfer (SET) to 1-OK and corresponding tetraphenyl epoxide (4).
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Affiliation(s)
- Solomon Volodarsky
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University Department Tel Aviv 69978 Israel
| | - Irina Malahov
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University Department Tel Aviv 69978 Israel
| | - Deependra Bawari
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University Department Tel Aviv 69978 Israel
| | - Mohand Diab
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University Department Tel Aviv 69978 Israel
| | - Naveen Malik
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science Rehovot 7610001 Israel
| | - Boris Tumanskii
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University Department Tel Aviv 69978 Israel
| | - Roman Dobrovetsky
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University Department Tel Aviv 69978 Israel
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4
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Peng TY, Xu ZY, Zhang FL, Li B, Xu WP, Fu Y, Wang YF. Dehydroxylative Alkylation of α‐Hydroxy Carboxylic Acids Derivatives via Spin‐center Shift. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202201329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Tian-Yu Peng
- University of Science and Technology of China Department of Chemistry CHINA
| | - Zhe-Yuan Xu
- University of Science and Technology of China Department of Chemistry CHINA
| | - Feng-Lian Zhang
- University of Science and Technology of China Department of Chemistry CHINA
| | - Bin Li
- University of Science and Technology of China Department of Chemistry CHINA
| | - Wen-Ping Xu
- University of Science and Technology of China Department of Chemistry CHINA
| | - Yao Fu
- University of Science and Technology of China Department of Chemistry CHINA
| | - Yi-Feng Wang
- University of Science and Technology of China Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry 96 Jinzhai Road 230026 Hefei CHINA
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Chen C, Daniliuc CG, Klabunde S, Hansen MR, Kehr G, Erker G. Generation of Boryl-nitroxide Radicals from a Boraalkene via the Nitroso Ene Reaction. Chem Sci 2022; 13:10891-10896. [PMID: 36320693 PMCID: PMC9491209 DOI: 10.1039/d2sc02485c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 08/09/2022] [Indexed: 11/21/2022] Open
Abstract
Examples of isolated boron substituted nitroxide radicals are rare. The reaction of the reactive cyclic boraalkene 3 with nitrosobenzene yields a mixture of the [2 + 2] cycloaddition product 4a, the B-nitroxide radicals 5a and 6a and the azoxybenzene co-product 7avia a bora nitroso ene reaction pathway, the boron analogue of the nitroso ene reaction. The products were separated by flash chromatography, and the B-nitroxide radicals were characterized by X-ray diffraction and EPR spectroscopy. Radical 5a was shown to be a hydrogen atom abstractor. Both the B-nitroxide radicals are more easily oxidized compared to e.g. TEMPO, as shown by cyclic voltammetry. The NHC-stabilized boraalkene reacts with nitrosobenzene to give a [2+2] cycloaddition product plus a pair of persistent borylnitroxide radicals. These are thought to be formed by means of a bora nitroso ene reaction followed by H-atom transfer.![]()
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Affiliation(s)
- Chaohuang Chen
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Sina Klabunde
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster Corrensstraße 28/3040 48149 Münster Germany
| | - Michael Ryan Hansen
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster Corrensstraße 28/3040 48149 Münster Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
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6
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Abstract
Boron-centred radicals (boryl radicals) are potential and attractive species in main group chemistry and synthetic chemistry. Recently, the development of boron compounds ligated by N-heterocyclic carbenes (NHCs) has sparked off advavnces in boryl radical chemistry because NHCs can highly stabilise boryl radicals by electronic and steric factors. This review highlights recent synthesis and reactions of such NHC-boryl radicals. From the standpoint of main group chemistry, examples of isolation or detection of unique NHC-boryl radicals are presented. From the standpoint of synthetic chemistry, on the other hand, the development of reactions of user-friendly NHC-boryl radicals, which has contributed to radical chemistry, organoboron chemistry and polymer science, is comprehensively described.
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Affiliation(s)
- Tsuyoshi Taniguchi
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
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