1
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Yu JW, Zhang CY, Chass GA, Zhang JX, Mu WH, Cao K. Pd-NHC catalysed regioselective activation of B(3,6)-H of o-carborane - a synergy between experiment and theory. Dalton Trans 2023; 52:10609-10620. [PMID: 37462420 DOI: 10.1039/d3dt01432k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Regioselective B-H activation of o-carboranes is an effective way for constructing o-carborane derivatives, which have broad applications in medicine, catalysis and the wider chemical industry. However, the mechanistic basis for the observed selectivities remains unresolved. Herein, a series of density functional theory (DFT) calculations were employed to characterise the palladium N-heterocyclic carbene (Pd-NHC) catalysed regioselective B(3,6)-diarylation of o-carboranes. Computational results at the IDSCRF(ether)-LC-ωPBE/BS1 and IDSCRF(ether)-LC-ωPBE/BS2 levels showed that the reaction undergoes a Pd(0) → Pd(II) → Pd(0) oxidation/reduction cycle, with the regioselective B(3)-H activation being the rate-determining step (RDS) for the full reaction profile. The computed RDS free energy barrier of 24.3 kcal mol-1 agrees well with the 82% yield of B(3,6)-diphenyl-o-carborane in ether solution at 298 K after 24 hours of reaction. The Ag2CO3 additive was shown to play a crucial role in lowering the RDS free energy barrier and facilitating the reaction. Natural charge population (NPA) and molecular surface electrostatic potential (ESP) analyses successfully predicted the experimentally observed regioselectivities, with electronic effects being revealed to be the dominant contributors to product selectivity. Steric hindrance was also shown to impact the reaction rate, as revealed by experimental and computational characterisation studies of substituents and ligand effects. Furthermore, computational predictions aligned with the experimental findings that NHC ligands outperform the phosphine ones for this particular reaction. Overall, the observed trends reported in this work are expected to assist in the rational optimisation of the efficiency and regioselectivity of this and related reactions.
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Affiliation(s)
- Jia-Wei Yu
- Faculty of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming, 650092, China.
| | - Cai-Yan Zhang
- State Key Laboratory of Environment-friendly Energy Materials & School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang, 621010, China.
| | - Gregory A Chass
- School of Physical and Chemical Sciences, Queen Mary, University of London, London, E1 4NS, UK
- Department of Chemistry and Biological Chemistry, McMaster University, Hamilton, L8S 4L8, Canada
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Jing-Xuan Zhang
- Faculty of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming, 650092, China.
| | - Wei-Hua Mu
- Faculty of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming, 650092, China.
| | - Ke Cao
- State Key Laboratory of Environment-friendly Energy Materials & School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang, 621010, China.
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2
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Jia H, Qiu Z. Recent Advances in Transition Metal-Catalyzed B—H Bond Activation for Synthesis of o-Carborane Derivatives with B—Heteroatom Bond. CHINESE J ORG CHEM 2023. [DOI: 10.6023/cjoc202211040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2023]
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3
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Gange GB, Humphries AL, Smith MD, Peryshkov DV. Activation of Alkynes by a Redox-Active Carboranyl Diphosphine and Formation of Boron-Containing Phosphacycles. Inorg Chem 2022; 61:18568-18573. [DOI: 10.1021/acs.inorgchem.2c02919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gayathri B. Gange
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, United States
| | - Amanda L. Humphries
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, United States
| | - Mark D. Smith
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, United States
| | - Dmitry V. Peryshkov
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, United States
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4
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Hamdaoui M, Liu F, Cornaton Y, Lu X, Shi X, Zhang H, Liu J, Spingler B, Djukic JP, Duttwyler S. An Iridium-Stabilized Borenium Intermediate. J Am Chem Soc 2022; 144:18359-18374. [PMID: 36173688 DOI: 10.1021/jacs.2c06298] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Exploration of new organometallic systems based on polyhedral boron clusters has the potential to solve challenging chemical problems such as the stabilization of reactive intermediates and transition-state-like species postulated for E-H (E = H, B, C, Si) bond activation reactions. We report on facile and clean B-H activation of a hydroborane by a new iridium boron cluster complex. The product of this reaction is an unprecedented and fully characterized transition metal-stabilized boron cation or borenium. Moreover, this intermediate bears an unusual intramolecular B···H interaction between the hydrogen originating from the activated hydroborane and the cyclometallated metal-bonded boron atom of the boron cluster. This B···H interaction is proposed to be an arrested insertion of hydrogen into the Bcage-metal bond and the initiation step for iridium "cage-walking" around the upper surface of the boron cluster. The "cage-walking" process is supported by the hydrogen-deuterium exchange observed at the boron cluster, and a mechanism is proposed on the basis of theoretical methods with a special focus on the role of noncovalent interactions. All new compounds were isolated and fully characterized by NMR spectroscopy and elemental analysis. Key compounds were studied by single crystal X-ray diffraction and X-ray photoelectron spectroscopy.
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Affiliation(s)
- Mustapha Hamdaoui
- Department of Chemistry, Zheijang University, Hangzhou 310027, China
| | - Fan Liu
- Department of Chemistry, Zheijang University, Hangzhou 310027, China
| | - Yann Cornaton
- Laboratoire de Chimie et Systémique Organométalliques, Institut de Chimie de Strasbourg UMR 7177 CNRS, Université de Strasbourg, Strasbourg 67000, France
| | - Xingyu Lu
- Instrumentation Service Center for Molecular Sciences, Westlake University, Hangzhou 310024, China
| | - Xiaohuo Shi
- Instrumentation Service Center for Molecular Sciences, Westlake University, Hangzhou 310024, China
| | - Huan Zhang
- Instrumentation Service Center for Molecular Sciences, Westlake University, Hangzhou 310024, China
| | - Jiyong Liu
- Department of Chemistry, Zheijang University, Hangzhou 310027, China
| | - Bernhard Spingler
- Department of Chemistry, University of Zurich, Zurich 8057, Switzerland
| | - Jean-Pierre Djukic
- Laboratoire de Chimie et Systémique Organométalliques, Institut de Chimie de Strasbourg UMR 7177 CNRS, Université de Strasbourg, Strasbourg 67000, France
| | - Simon Duttwyler
- Department of Chemistry, Zheijang University, Hangzhou 310027, China
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5
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Zhou P, Chen Y, Xie Z. Iron-Catalyzed Selective B–H Activation for 4/5-fold Methylation and Arylation of Carboranes. ACS Catal 2022. [DOI: 10.1021/acscatal.2c02120] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Peng Zhou
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China
| | - Yu Chen
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China
| | - Zuowei Xie
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China
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6
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Jei BB, Yang L, Ackermann L. Selective Labeling of Peptides with o-Carboranes via Manganese(I)-Catalyzed C-H Activation. Chemistry 2022; 28:e202200811. [PMID: 35420234 PMCID: PMC9320968 DOI: 10.1002/chem.202200811] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Indexed: 12/15/2022]
Abstract
A robust method for the selective labeling of peptides via manganese(I) catalysis was devised to achieve the C-2 alkenylation of tryptophan containing peptides with 1-ethynyl-o-carboranes. The manganese-catalyzed C-H activation was accomplished with high catalytic efficiency, and featured low toxicity, high functional group tolerance and excellent E-stereoselectivity. This approach unravels a promising tool for the assembly of o-carborane with structurally complex peptides of relevance to applications in boron neutron capture therapy.
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Affiliation(s)
- Becky Bongsuiru Jei
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tamannstraße 2, 37077, Göttingen, Germany.,Woehler Research Institute for Sustainable Chemistry (WISCh), Georg-August-Universität Göttingen, Tammannstraße 2, 37077, Göttingen, Germany
| | - Long Yang
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tamannstraße 2, 37077, Göttingen, Germany.,Woehler Research Institute for Sustainable Chemistry (WISCh), Georg-August-Universität Göttingen, Tammannstraße 2, 37077, Göttingen, Germany
| | - Lutz Ackermann
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tamannstraße 2, 37077, Göttingen, Germany.,Woehler Research Institute for Sustainable Chemistry (WISCh), Georg-August-Universität Göttingen, Tammannstraße 2, 37077, Göttingen, Germany
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7
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Chen Y, Du F, Tang L, Xu J, Zhao Y, Wu X, Li M, Shen J, Wen Q, Cho CH, Xiao Z. Carboranes as unique pharmacophores in antitumor medicinal chemistry. Mol Ther Oncolytics 2022; 24:400-416. [PMID: 35141397 PMCID: PMC8807988 DOI: 10.1016/j.omto.2022.01.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Carborane is a carbon-boron molecular cluster that can be viewed as a 3D analog of benzene. It features special physical and chemical properties, and thus has the potential to serve as a new type of pharmacophore for drug design and discovery. Based on the relative positions of two cage carbons, icosahedral closo-carboranes can be classified into three isomers, ortho-carborane (o-carborane, 1,2-C2B10H12), meta-carborane (m-carborane, 1,7-C2B10H12), and para-carborane (p-carborane, 1,12-C2B10H12), and all of them can be deboronated to generate their nido- forms. Cage compound carborane and its derivatives have been demonstrated as useful chemical entities in antitumor medicinal chemistry. The applications of carboranes and their derivatives in the field of antitumor research mainly include boron neutron capture therapy (BNCT), as BNCT/photodynamic therapy dual sensitizers, and as anticancer ligands. This review summarizes the research progress on carboranes achieved up to October 2021, with particular emphasis on signaling transduction pathways, chemical structures, and mechanistic considerations of using carboranes.
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Affiliation(s)
- Yu Chen
- Laboratory of Molecular Pharmacology, Department of Pharmacology, School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Fukuan Du
- Laboratory of Molecular Pharmacology, Department of Pharmacology, School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Liyao Tang
- Laboratory of Molecular Pharmacology, Department of Pharmacology, School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Jinrun Xu
- Laboratory of Molecular Pharmacology, Department of Pharmacology, School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Yueshui Zhao
- Laboratory of Molecular Pharmacology, Department of Pharmacology, School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Xu Wu
- Laboratory of Molecular Pharmacology, Department of Pharmacology, School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Mingxing Li
- Laboratory of Molecular Pharmacology, Department of Pharmacology, School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Jing Shen
- Laboratory of Molecular Pharmacology, Department of Pharmacology, School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Qinglian Wen
- Department of Oncology, Affiliated Hospital of Southwest Medical University, Luzhou 646000, China
- Luzhou Key Laboratory of Cell Therapy & Cell Drugs, Southwest Medical University, Luzhou 646000, China
| | - Chi Hin Cho
- Laboratory of Molecular Pharmacology, Department of Pharmacology, School of Pharmacy, Southwest Medical University, Luzhou 646000, China
- Luzhou Key Laboratory of Cell Therapy & Cell Drugs, Southwest Medical University, Luzhou 646000, China
- Faculty of Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong 999077, China
| | - Zhangang Xiao
- Department of Oncology, Affiliated Hospital of Southwest Medical University, Luzhou 646000, China
- Luzhou Key Laboratory of Cell Therapy & Cell Drugs, Southwest Medical University, Luzhou 646000, China
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8
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Zhang J, Xie Z. Advances in transition metal catalyzed selective B H functionalization of o-carboranes. ADVANCES IN CATALYSIS 2022. [DOI: 10.1016/bs.acat.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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9
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Ge Y, Qiu Z, Xie Z. Pd-Catalyzed One-Pot Synthesis of Difunctionalized o-Carboranes via Construction of B—C and B—Heteroatom Bonds ※. ACTA CHIMICA SINICA 2022. [DOI: 10.6023/a21120597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Liu J, Fu D, Chen Z, Li T, Qu LB, Li SJ, Zhang W, Lan Y. Regioselectivity of Pd-catalyzed o-carborane arylation: a theoretical view. Org Chem Front 2022. [DOI: 10.1039/d2qo00046f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
B(3)-Arylation is unfavorable because the steric repulsion between the substituent group on C(2) and the metal moiety would lead to significant distortion of o-carborane and would result in a higher activation energy for reductive elimination.
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Affiliation(s)
- Jiying Liu
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Dongmin Fu
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Zitong Chen
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Tiantian Li
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Ling-Bo Qu
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Shi-Jun Li
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Wenjing Zhang
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Yu Lan
- Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
- School of Chemistry and Chemical Engineering, and Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 400030, China
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11
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Ni H, Lu Z, Xie Z. Light-enabled alkenylation of iodocarboranes with unactivated alkenes. Dalton Trans 2021; 51:104-110. [PMID: 34870668 DOI: 10.1039/d1dt03726a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of alkenylated-o-carboranes via photoalkenylation of iodocarboranes with unactivated alkenes has been achieved. This strategy features a transition metal-free protocol, a light-promoted reaction under mild reaction conditions, broad substrate scope and good functional group tolerance. Control experiments suggest that the reaction may involve the cage C-centered radical species.
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Affiliation(s)
- Hangcheng Ni
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin N. T., Hong Kong, China.
| | - Zhenpin Lu
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin N. T., Hong Kong, China.
| | - Zuowei Xie
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin N. T., Hong Kong, China.
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12
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Cheng B, Chen Y, Zhou P, Xie Z. Rhodium-catalyzed sequential B(3)-, B(4)-, and B(5)-trifunctionalization of o-carboranes with three different substituents. Chem Commun (Camb) 2021; 58:629-632. [PMID: 34913450 DOI: 10.1039/d1cc05936j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A rhodium-catalyzed one-pot trifunctionalization of o-carboranes with three different substituents via a carboxy group directed sequential B(5)-alkenylation, B(4)-alkyne annulation and B(3)-acyloxylation has been developed for the first time, leading to the synthesis of a new class of B(3,4,5)-trisubstituted o-carborane derivatives. Treatment of 1-COOH-2-CH3-o-C2B10H10 with ArCCAr in the presence of a [Cp*RhCl2]2 catalyst and a Cu(OPiv)2 oxidant gave 1,4-[COOC(Ar)C(Ar)]-2-Me-3-OPiv-5-[C(Ar)CH(Ar)-o-C2B10H7 in good to high yields. This protocol represents a new strategy for the catalytic selective polyfunctionalization of carboranes with different substituents.
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Affiliation(s)
- Biao Cheng
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
| | - Yu Chen
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
| | - Peng Zhou
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
| | - Zuowei Xie
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
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13
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Cao HJ, Wei X, Sun F, Zhang X, Lu C, Yan H. Metal-catalyzed B-H acylmethylation of pyridylcarboranes: access to carborane-fused indoliziniums and quinoliziniums. Chem Sci 2021; 12:15563-15571. [PMID: 35003585 PMCID: PMC8654026 DOI: 10.1039/d1sc05296a] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 11/19/2021] [Indexed: 12/11/2022] Open
Abstract
Metal-catalyzed mono-acylmethylation of pyridylcarboranes has been realized using α-carbonyl sulfoxonium ylides as a coupling partner. The reaction features high efficiency, excellent site-selectivity and good functional group tolerance. In the presence of pyridyl and enolizable acylmethyl groups, a post-coordination mode has been proposed and validated by in situ high resolution mass spectroscopy (HRMS) to rationalize the unique mono-substitution. Post-functionalization at the newly incorporated alkyl site provides additional utility of this method, including the construction of carborane-fused indoliziniums and quinoliziniums. We believe that these mono-alkylated carboranes, together with their post-functionalized derivatives, may find applications in luminescent materials and drug discovery in the near future.
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Affiliation(s)
- Hou-Ji Cao
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University Nanjing Jiangsu 210023 P. R. China
| | - Xing Wei
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University Nanjing Jiangsu 210023 P. R. China
| | - Fangxiang Sun
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University Nanjing Jiangsu 210023 P. R. China
| | - Xiaolei Zhang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University Nanjing Jiangsu 210023 P. R. China
| | - Changsheng Lu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University Nanjing Jiangsu 210023 P. R. China
| | - Hong Yan
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University Nanjing Jiangsu 210023 P. R. China
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14
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Eleazer BJ, Jayaweera HDAC, Gange GB, Smith MD, Martin CR, Park KC, Popov AA, Peryshkov DV. Bimetallic Ru-Pd and Trimetallic Ru-Pd-Cu Assemblies on the Carborane Cluster Surface. Inorg Chem 2021; 60:16911-16916. [PMID: 34710327 DOI: 10.1021/acs.inorgchem.1c02799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis of well-defined heterometallic complexes remains a frontier challenge in inorganic chemistry. We report an approach that relies on the sequential insertion of electrophilic metal fragments into electron-rich Ru-B bonds of the η2-BB-carboryne complex (POBBOP)Ru(CO)2 [POBBOP = 1,7-OP(iPr)2-m-2,6-dehydrocarborane]. Utilizing this synthetic strategy, bimetallic (POBBOP)(Ru)(CO)2[Pd(PtBu3)] and trimetallic (POBBOP)(Ru)(CO)2[Pd(PtBu3)](CuBr) complexes were selectively prepared. Structural and theoretical analysis of the features of chemical bonding within Ru-B-B-Cu and Ru-B-B-Pd fragments is presented.
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Affiliation(s)
- Bennett J Eleazer
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, United States
| | - H D A Chathumal Jayaweera
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, United States
| | - Gayathri B Gange
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, United States
| | - Mark D Smith
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, United States
| | - Corey R Martin
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, United States
| | - Kyoung Chul Park
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, United States
| | - Alexey A Popov
- Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Dmitry V Peryshkov
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, United States
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15
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Abstract
Carboranes are a class of polyhedral carbon-boron molecular clusters featuring three-dimensional aromaticity, which are often considered as 3D analogues of benzene. Their unique structural and electronic properties make them invaluable building blocks for applications ranging from functional materials to versatile ligands to pharmaceuticals. Thus, selective functionalization of carboranes has received tremendous research interest. In earlier days, the vast majority of the works in this area were focused on cage carbon functionalization via facile deprotonation of cage CH, followed by reaction with electrophiles. On the contrary, cage B-H activation is very challenging since the 10 B-H bonds on o-carborane are very similar, and how to achieve the desired transformation at specific boron vertex is a long-standing issue.As carbon is considered more electronegative than boron, this property results in different vertex charges on the o-carborane cage, which follow the order B(3,6)-H ≪ B(4,5,7,11)-H < B(8,10)-H < B(9,12)-H. We thought that this difference may trigger the favorite interaction of a proper transition metal complex with a specific B-H bond of carborane, which could be utilized to solve the selectivity issue. Accordingly, our strategy is described as follows: (1) electron-rich transition metal catalysts are good for the activation of the most electron-deficient B(3,6)-H bonds (connected to both cage C-H vertices); (2) electron-deficient transition metal catalysts are good for the activation of the relatively electron-rich B(8,9,10,12)-H bonds (with no bonding to either cage C-H vertices); and (3) directing-group-assisted transition metal catalysis is appropriate for the activation of the B(4,5,7,11)-H bonds (connected to only one cage C-H vertex), whose vertex charges lie in the middle of the range for the 10 B-H bonds. This strategy has been successfully applied by our laboratory and other groups in the development of a series of synthetic routes for catalytic selective activation of B-H bonds of the carborane cage, resulting in the synthesis of a large number of cage-boron-functionalized carborane derivatives in a regioselective and catalytic fashion. Subsequently, significant progress in this emerging area has been made.In 2013 we reported the selective tetrafluorination of o-carboranes at the B(8,9,10,12)-H bonds using an electron-deficient Pd(II) salt, [Pd(MeCN)4][BF4], as the catalyst. In 2014 we disclosed the first example of carboxy-directed alkenylation of o-carboranes at the B(4) vertex promoted by an Ir(III) catalyst. Subsequently, in 2017 we presented an electron-rich Ir(I)-catalyzed diborylation of o-carboranes at the B(3,6)-H bonds. We also uncovered the first example of Pd-catalyzed asymmetric synthesis of chiral-at-cage o-carboranes in 2018. These proof-of-principle studies have greatly stimulated research activities in selective B-H activation of carboranes and boron clusters enabled by transition metal catalysts. We have so far developed a toolbox of synthetic methods for selective catalytic cage B-olefination, -arylation, -alkenylation, -alkynylation, -oxygenation, -sulfenylation, -borylation, -halogenation, and -amination. We have recently expanded our research to base metal catalysis. As the field progresses, we expect that other methods for regioselective cage B-H activation will be invented, and the results detailed in this Account will promote these efforts.
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Affiliation(s)
- Zaozao Qiu
- Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Zuowei Xie
- Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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Ge Y, Qiu Z, Xie Z. Pd-catalyzed selective tetrafunctionalization of diiodo- o-carboranes. Chem Commun (Camb) 2021; 57:8071-8074. [PMID: 34296721 DOI: 10.1039/d1cc03449a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A palladium-catalyzed highly selective tetrafunctionalization of 3,6-I2-o-carborane and 4,7-I2-o-carborane has been developed, leading to the preparation of 3,6-dialkenyl-4,11-R2-o-carboranes and 4,7-dialkenyl-5,11-R2-o-carboranes (R = alkyl, allyl and aryl) in moderate to excellent yields. This represents a new strategy for selective synthesis of polyfunctionalized o-carborane derivatives via a one-pot process.
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Affiliation(s)
- Yixiu Ge
- Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Rd, Shanghai 200032, China.
| | - Zaozao Qiu
- Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Rd, Shanghai 200032, China. and CAS Key Laboratory of Energy Regulation Materials, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Rd, Shanghai 200032, China
| | - Zuowei Xie
- Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Rd, Shanghai 200032, China. and Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China
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17
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Chen Y, Lyu H, Quan Y, Xie Z. Fe-Catalyzed Intramolecular B-H/C-H Dehydrogenative Coupling: Synthesis of Carborane-Fused Nitrogen Heterocycles. Org Lett 2021; 23:4163-4167. [PMID: 33983035 DOI: 10.1021/acs.orglett.1c01104] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We disclose herein the first example of iron-catalyzed regioselective intramolecular C-H/B-H dehydrogenative coupling, affording unprecedented C,B-substituted carborane-fused phenanthroline derivatives. The 8-aminoquinoline type auxiliaries not only serve as the bidentate directing groups but also ingeniously become the core part of the final products. The mechanistic hypothesis includes B-H activation, directing group rotation promoted by trans effect, C-H activation, and reductive elimination.
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Affiliation(s)
- Yu Chen
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China
| | - Hairong Lyu
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China
| | - Yangjian Quan
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China
| | - Zuowei Xie
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China
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18
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Cui PF, Liu XR, Guo ST, Lin YJ, Jin GX. Steric-Effects-Directed B-H Bond Activation of para-Carboranes. J Am Chem Soc 2021; 143:5099-5105. [PMID: 33761746 DOI: 10.1021/jacs.1c00779] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The controllable B-H bond activation of carboranes has long been a compelling challenge. However, as the symmetry of para-carborane places the same charge on all of its ten boron atoms, controlling the regiochemistry of B-H bond activation in these molecules has remained out of reach ever since their discovery. Herein, we describe how to use steric effects to achieve a regioselective process for B-H activation of para-carborane. In this strategy, B(2,8)-H or B(2,7)-H activation patterns were achieved by taking advantage of the π-π interactions between pyridine ligands. Interestingly, by employing host-guest interactions in metallacage compounds, B(2,8)-H bond activation could be avoided and exclusive B(2,9)-H bond activation can be achieved. Steric hindrance was also found to be beneficial for regioselective B(2,8)-H bond activation in metallacage species. In this work, we demonstrate that steric effects can be a promising driving force for controllable activation of the B-H bonds of carboranes and open new opportunities in this field.
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Affiliation(s)
- Peng-Fei Cui
- State Key Laboratory of Molecular Engineering of Polymers, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai, 200433, P. R. China
| | - Xin-Ran Liu
- State Key Laboratory of Molecular Engineering of Polymers, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai, 200433, P. R. China
| | - Shu-Ting Guo
- State Key Laboratory of Molecular Engineering of Polymers, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai, 200433, P. R. China
| | - Yue-Jian Lin
- State Key Laboratory of Molecular Engineering of Polymers, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai, 200433, P. R. China
| | - Guo-Xin Jin
- State Key Laboratory of Molecular Engineering of Polymers, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai, 200433, P. R. China
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19
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Liu XR, Cui PF, Guo ST, Yuan RZ, Jin GX. Stepwise B–H bond activation of a meta-carborane. Inorg Chem Front 2021. [DOI: 10.1039/d1qi00732g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Stepwise multiple B–H bond activation is a major challenge in synthetic chemistry.
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Affiliation(s)
- Xin-Ran Liu
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials; State Key Laboratory of Molecular Engineering of Polymers, Department of Chemistry, Fudan University, Shanghai 200438, P. R. China
| | - Peng-Fei Cui
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials; State Key Laboratory of Molecular Engineering of Polymers, Department of Chemistry, Fudan University, Shanghai 200438, P. R. China
| | - Shu-Ting Guo
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials; State Key Laboratory of Molecular Engineering of Polymers, Department of Chemistry, Fudan University, Shanghai 200438, P. R. China
| | - Run-Ze Yuan
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials; State Key Laboratory of Molecular Engineering of Polymers, Department of Chemistry, Fudan University, Shanghai 200438, P. R. China
| | - Guo-Xin Jin
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials; State Key Laboratory of Molecular Engineering of Polymers, Department of Chemistry, Fudan University, Shanghai 200438, P. R. China
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, P. R. China
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