1
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Willcox DR, Cocco E, Nichol GS, Carlone A, Thomas SP. Catalytic Access to Diastereometrically Pure Four- and Five-Membered Silyl-Heterocycles Using Transborylation. Angew Chem Int Ed Engl 2024; 63:e202401737. [PMID: 38578174 DOI: 10.1002/anie.202401737] [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: 01/24/2024] [Revised: 03/19/2024] [Accepted: 04/03/2024] [Indexed: 04/06/2024]
Abstract
Silyl-heterocycles offer a unique handle to expand and explore chemical space, reactivity, and functionality. The shortage of catalytic methods for the preparation of diverse and functionalized silyl-heterocycles however limits widespread exploration and exploitation. Herein the borane-catalyzed intramolecular 1,1-carboboration of silyl-alkynes has been developed for the synthesis of 2,3-dihydrosilolyl and silylcyclobut-2-enyl boronic esters. Successful, catalytic carboboration has been achieved on a variety of functionally diverse silyl-alkynes, using a borane catalyst and transborylation-enabled turnover. Mechanistic studies, including 13C-labelling, computational studies, and single-turnover experiments, suggest a reaction pathway proceeding by 1,2-hydroboration, 1,1-carboboration, and transborylation to release the alkenyl boronic ester product and regenerate the borane catalyst.
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Affiliation(s)
- Dominic R Willcox
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ, Edinburgh, United Kingdom
| | - Emanuele Cocco
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ, Edinburgh, United Kingdom
- Department of Physical and Chemical Sciences, Università degli Studi dell'Aquila, via Vetoio, 67100, L'Aquila, Italy
| | - Gary S Nichol
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ, Edinburgh, United Kingdom
| | - Armando Carlone
- Department of Physical and Chemical Sciences, Università degli Studi dell'Aquila, via Vetoio, 67100, L'Aquila, Italy
| | - Stephen P Thomas
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ, Edinburgh, United Kingdom
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2
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Réant BLL, Whitehead GFS, Mehta M. Zintl Clusters as a Platform for Lewis Acid Catalysis. Inorg Chem 2024. [PMID: 38814137 DOI: 10.1021/acs.inorgchem.4c00433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
Clusters of the main group elements phosphorus and arsenic, commonly categorized as Zintl clusters, have been known for over a century. And, only now is the application of these systems as catalysts for organic synthesis being investigated. In this work, boranes are tethered via an aliphatic linker to Zintl-based clusters and their Lewis acidity is examined experimentally, by the Gutmann-Beckett test and competency in the hydroborative reduction of six organic substrates, as well as computationally, by fluoride ion affinity and hydride ion affinity methods. The effects of tuning the aliphatic linker length, substituents at the boron, and changing the cluster from a seven-atom phosphorus system to a seven-atom arsenic system on reactivity are studied.
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Affiliation(s)
- Benjamin L L Réant
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - George F S Whitehead
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Meera Mehta
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
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3
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Ariai J, Gellrich U. The entropic penalty for associative reactions and their physical treatment during routine computations. Phys Chem Chem Phys 2023; 25:14005-14015. [PMID: 37161492 DOI: 10.1039/d3cp00970j] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A systematic study of the entropic penalty for associative reactions is presented. It is shown that computed solution-phase Gibbs free energies typically overestimate entropic contributions. This entropic penalty for associative reactions in solution, i.e., if the number of particles decreases along the reaction coordinate (sum of stoichiometric numbers ), originates from the insufficient treatment of entropic effects by implicit solvent models. We propose an additive correction scheme to Gibbs free energies that is suitable for routine applications by non-expert users. This correction is based on Garza's formalism for the solution-phase entropy [A. J. Garza, J. Chem. Theory Comput., 2019, 15, 3204.] that is physically sound and embedded into an efficient black-box type algorithm. To critically evaluate the entropic penalty and its proposed treatment, we compiled an experimental benchmark set of 31 ΔrG and 22 in 15 different solvents. Using a representative best-practice computational protocol (at wave function theory (WFT) based DLPNO-CCSD(T) and density functional theory (DFT) based revDSD-PBEP86-D4 level with an implicit solvent model), we determined a sizeable entropic penalty ranging from 2-11 kcal mol-1. Using the correction scheme presented herein, the entropic penalty is corrected to the chemical accuracy of ≤1 kcal mol-1 (WFT and DFT). The same applies to at the WFT level. Barriers at the DFT level are overestimated by 2 kcal mol-1 (classic) and underestimated by 2 kcal mol-1 (corrected). This effect is attributed to the finding that barriers computed at the DFT level are systematically 2-3 kcal mol-1 lower than barriers obtained with WFT.
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Affiliation(s)
- Jama Ariai
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
| | - Urs Gellrich
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
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4
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Willcox DR, Thomas SP. Group 13 exchange and transborylation in catalysis. Beilstein J Org Chem 2023; 19:325-348. [PMID: 36998308 PMCID: PMC10043741 DOI: 10.3762/bjoc.19.28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/24/2023] [Indexed: 04/01/2023] Open
Abstract
Catalysis is dominated by the use of rare and potentially toxic transition metals. The main group offers a potentially sustainable alternative for catalysis, due to the generally higher abundance and lower toxicity of these elements. Group 13 elements have a rich catalogue of stoichiometric addition reactions to unsaturated bonds but cannot undergo the redox chemistry which underpins transition-metal catalysis. Group 13 exchange reactions transfer one or more groups from one group 13 element to another, through σ-bond metathesis; where boron is both of the group 13 elements, this is termed transborylation. These redox-neutral processes are increasingly being used to render traditionally stoichiometric group 13-mediated processes catalytic and develop new catalytic processes, examples of which are the focus of this review.
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Affiliation(s)
- Dominic R Willcox
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, EH9 3FJ, United Kingdom
| | - Stephen P Thomas
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, EH9 3FJ, United Kingdom
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5
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Phatake RS, Averdunk A, Würtele C, Gellrich U. Piers’ Borane-Catalyzed Dimerization of Arylallenes via Transborylation: A Synthetic and Mechanistic Study. ACS Catal 2022. [DOI: 10.1021/acscatal.2c04605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ravindra S. Phatake
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
| | - Arthur Averdunk
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
| | - Christian Würtele
- Institut für Anorganische und Analytische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
| | - Urs Gellrich
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
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6
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Thomas SP, Bage AD, Nicholson K, Hunt TA, Langer T. Transborylation-Enabled Boron Catalysis. SYNTHESIS-STUTTGART 2022. [DOI: 10.1055/s-0040-1720046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
AbstractThis review highlights transborylation (controlled boron-boron exchange) and its applications as a turnover strategy in boron-catalysed methodologies. Catalytic applications of B–C, B–O, B–N, B–F, B–S, and B–Se transborylations are discussed in the context of transborylation-enabled catalysis, across a wide range of organic transformations including hydroboration, C–C bond formation, C–H borylation, chemoselective reduction, and asymmetric reduction.1 Introduction2 B–C Transborylation3 B–O Transborylation4 B–N Transborylation5 B–F Transborylation6 B–S Transborylation7 Conclusion
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Affiliation(s)
| | - Andrew D. Bage
- EaStCHEM School of Chemistry, The University of Edinburgh
| | | | | | - Thomas Langer
- Pharmaceutical Technology & Development, Chemical Development U.K., AstraZeneca
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7
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Moreno González A, Nicholson K, Llopis N, Nichol GS, Langer T, Baeza A, Thomas SP. Diastereoselective, Catalytic Access to Cross-Aldol Products Directly from Esters and Lactones. Angew Chem Int Ed Engl 2022; 61:e202209584. [PMID: 35916601 PMCID: PMC9804986 DOI: 10.1002/anie.202209584] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Indexed: 01/09/2023]
Abstract
High oxidation-state carbonyl coupling partners including esters and lactones were reacted with enones to give aldol-type products directly using two-fold organoborane catalysis. This new retrosynthetic disconnection to aldol-type products is compatible with enolisable coupling partners, without self-condensation, and couples the high reactivity of secondary dialkylboranes with the stability of pinacolboronic esters. Excellent chemoselectivity, substrate scope (including those containing reducible functionalities and free alcohols) and diastereocontrol were achieved to access both the syn- and anti-aldol-type products. Mechanistic studies confirmed the two-fold catalytic role of the single secondary borane catalyst for boron enolate formation and formation of an aldehyde surrogate from the ester or lactone coupling partner.
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Affiliation(s)
- Adrián Moreno González
- EaStCHEM School of ChemistryUniversity of EdinburghDavid Brewster RoadEdinburghEH9 3FJUK
| | - Kieran Nicholson
- EaStCHEM School of ChemistryUniversity of EdinburghDavid Brewster RoadEdinburghEH9 3FJUK
| | - Natalia Llopis
- EaStCHEM School of ChemistryUniversity of EdinburghDavid Brewster RoadEdinburghEH9 3FJUK
| | - Gary S. Nichol
- EaStCHEM School of ChemistryUniversity of EdinburghDavid Brewster RoadEdinburghEH9 3FJUK
| | - Thomas Langer
- AstraZeneca Pharmaceutical Technology & DevelopmentChemical Development UKSilk RoadMacclesfieldSK10 2NAUK
| | - Alejandro Baeza
- Instituto de Síntesis Orgánica and Dpto. de Química OrgánicaUniversidad de AlicanteApdo. 9903080AlicanteSpain
| | - Stephen P. Thomas
- EaStCHEM School of ChemistryUniversity of EdinburghDavid Brewster RoadEdinburghEH9 3FJUK
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8
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Pradhan S, Sankar RV, Gunanathan C. A Boron-Nitrogen Double Transborylation Strategy for Borane-Catalyzed Hydroboration of Nitriles. J Org Chem 2022; 87:12386-12396. [PMID: 36045008 DOI: 10.1021/acs.joc.2c01655] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Organoborane-catalyzed hydroboration of nitriles provides N,N-diborylamines, which act as efficient synthons for the synthesis of primary amines and secondary amides. Known nitrile hydroboration methods are dominated by metal catalysis. Simple and metal-free hydroboration of nitriles using diborane [H-B-9-BBN]2 as a catalyst and pinacolborane as a turnover reagent is reported. The reaction of monomeric H-B-9-BBN with nitriles leads to the hydrido-bridged diborylimine intermediate; a subsequent sequential double hydroboration-transborylation pathway involving B-N/B-H σ bond metathesis is proposed.
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Affiliation(s)
- Subham Pradhan
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar 752050, India
| | - Raman Vijaya Sankar
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar 752050, India
| | - Chidambaram Gunanathan
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar 752050, India
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9
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Nicholson K, Peng Y, Llopis N, Willcox DR, Nichol GS, Langer T, Baeza A, Thomas SP. Boron-Catalyzed, Diastereo- and Enantioselective Allylation of Ketones with Allenes. ACS Catal 2022; 12:10887-10893. [PMID: 36082052 PMCID: PMC9442582 DOI: 10.1021/acscatal.2c03158] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/11/2022] [Indexed: 01/04/2023]
Affiliation(s)
- Kieran Nicholson
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Yuxuan Peng
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Natalia Llopis
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Dominic R. Willcox
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Gary S. Nichol
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Thomas Langer
- Pharmaceutical Technology & Development, Chemical Development U.K., AstraZeneca, Silk Road, Macclesfield SK10 2NA, United Kingdom
| | - Alejandro Baeza
- Instituto de Síntesis Orgánica and Dpto. de Química Orgánica, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain
| | - Stephen P. Thomas
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
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10
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Thomas S, González AM, Nicholson K, Llopis N, Nichol GS, Langer T, Baeza A. Diastereoselective, Catalytic Access to Cross‐aldol Products Directly from Esters and Lactones. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202209584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Stephen Thomas
- University of Edinburgh School of Chemistry Joseph Black Building,King's Buildings, West Mains Road EH9 3FJ Edinburgh UNITED KINGDOM
| | | | - Kieran Nicholson
- The University of Edinburgh School of Chemistry School of Chemistry UNITED KINGDOM
| | - Natalia Llopis
- The University of Edinburgh School of Chemistry School of Chemistry UNITED KINGDOM
| | - Gary S. Nichol
- The University of Edinburgh School of Chemistry School of Chemistry UNITED KINGDOM
| | - Thomas Langer
- AstraZeneca UK Ltd Macclesfield Chemical Development UK UNITED KINGDOM
| | - Alejandro Baeza
- Universidad de Alicante: Universitat d'Alacant Dpto. de Química Orgánica SPAIN
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11
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Feng Q, Li S, Li Z, Yan Q, Lin X, Song L, Zhang X, Wu YD, Sun J. Ru-Catalyzed Hydroboration of Ynones Leads to a Nontraditional Mode of Reactivity. J Am Chem Soc 2022; 144:14846-14855. [PMID: 35900878 DOI: 10.1021/jacs.2c06024] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although hydroboration of simple ketones and alkynes have been well-established, little is known about the unique hydroboration reactivity for ynones, a family of important building blocks. Herein we report a new reaction mode of ynones leading to structurally novel and synthetically useful but previously inaccessible products, vinyl α-hydroxylboronates, under mild ruthenium-catalyzed hydroboration conditions. This reaction features high efficiency, a broad scope, and complete chemo-, regio-, and stereoselectivity, in spite of many possible competitive pathways. Both control experiments and detailed DFT studies suggested a two-step mechanism, involving initial rate-determining conjugate addition of hydroborane to form the key boryl allenolate intermediate followed by a fast second hydroboration of the enolate motif of the allenolate. Notably, direct 1,4-addition of hydroborane to carbonyl-conjugated alkynes also represents a new mode of reactivity. Despite the overwhelming complexity of this process, which involves selectivity control in almost every step, a thorough and detailed computation on a large set of possible transition states explained the unusual reactivity and intrinsic origin of selectivity.
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Affiliation(s)
- Qiang Feng
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong SAR 999077, China
| | - Shijia Li
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong SAR 999077, China.,Shenzhen Bay Laboratory, Shenzhen 518055, China
| | - Zhiyang Li
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong SAR 999077, China
| | - Qiaolin Yan
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong SAR 999077, China
| | - Xiangfeng Lin
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong SAR 999077, China
| | - Lijuan Song
- School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Xinhao Zhang
- Shenzhen Bay Laboratory, Shenzhen 518055, China.,Lab of Computational Chemistry and Drug Design, State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Yun-Dong Wu
- Shenzhen Bay Laboratory, Shenzhen 518055, China.,Lab of Computational Chemistry and Drug Design, State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Jianwei Sun
- Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong SAR 999077, China.,Shenzhen Research Institute, HKUST, No. 9 Yuexing 1st Road, Shenzhen 518057, China
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12
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Hümpfner E, Buzsáki D, Kelemen Z. DFT mechanistic investigation of the 1,2‐reduction of α,β‐unsaturated ynones. ChemistrySelect 2022. [DOI: 10.1002/slct.202201768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Evelyn Hümpfner
- Department of Inorganic and Analytical Chemistry Budapest University of Technology and Economics Műegyetem rakpart 3 H-1111 Budapest Hungary
| | - Dániel Buzsáki
- Department of Inorganic and Analytical Chemistry Budapest University of Technology and Economics Műegyetem rakpart 3 H-1111 Budapest Hungary
- MTA-BME Computation Driven Chemistry Research Group Műegyetem rakpart 3 H-1111 Budapest Hungary
| | - Zsolt Kelemen
- Department of Inorganic and Analytical Chemistry Budapest University of Technology and Economics Műegyetem rakpart 3 H-1111 Budapest Hungary
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13
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Qin XL, Xu LJ, Han FS. Recent Advances in Organocatalyzed Asymmetric Reduction of Prochiral Ketones: An Update. SYNTHESIS-STUTTGART 2022. [DOI: 10.1055/a-1697-7758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
AbstractChiral alcohols are important synthetic intermediates and building blocks for the synthesis of drugs, agrochemicals, and natural products. Asymmetric reduction of prochiral ketones has been the most investigated method for accessing chiral alcohols. In this regard, organocatalyzed asymmetric reduction, as a complementary method to transition-metal- and enzyme-catalyzed reactions, has attracted tremendous interest in the past decades due to the reactions with such catalysts being metal-free and easy to operate, and principally, the ease of recovery and the ability to reuse the catalysts. Following up on a comprehensive overview on organocatalyzed asymmetric reductions of prochiral ketones in early 2018, this short review is intended to summarize the recent progress in this area from the beginning of 2018 until the end of August 2021.1 Introduction2 Boron-Based Chiral Organocatalysts2.1 Boron-Containing Chiral Schiff Base Catalysts2.2 Chiral Alpine-Borane Catalysts2.3 Boron-Containing Chiral Frustrated Lewis Pair Catalysts2.4 Chiral Borate Ester–Amine Complex Catalysts3 Phosphorus-Based Chiral Organocatalysts3.1 Chiral Phosphoric Acid Organocatalysts3.2 Chiral Phosphinamide and Phosphoramide Organocatalysts4 Chiral Ionic Liquid Organocatalysts5 Chiral-Oxazoline-Based Organocatalysts6 Conclusion and Outlook
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Affiliation(s)
- Xu-Long Qin
- CAS Key Laboratory of High-Performance Synthetic Rubber and its Composite Materials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences
| | - Li-Jun Xu
- CAS Key Laboratory of High-Performance Synthetic Rubber and its Composite Materials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences
- University of Science and Technology of China
| | - Fu-She Han
- CAS Key Laboratory of High-Performance Synthetic Rubber and its Composite Materials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences
- University of Science and Technology of China
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14
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Légaré Lavergne J, To HM, Fontaine FG. Boric acid as a precatalyst for BH 3-catalyzed hydroboration. RSC Adv 2021; 11:31941-31949. [PMID: 35495511 PMCID: PMC9041564 DOI: 10.1039/d1ra05945a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 09/11/2021] [Indexed: 01/23/2023] Open
Abstract
We report that boric acid, BO3H3, is a good precatalyst for the BH3-catalyzed hydroboration of esters using pinacolborane as a borylation agent. Using microwave irradiation as an energy source, we demonstrated that a dozen esters were converted into the corresponding boronate ethers in good yields. It was also possible to use boric acid as a precatalyst to reduce carbonates and alkynes. Considering the hazardous and pyrophoric nature of BH3 solutions, boric acid proves to be a safe and green precatalyst for the metal-free reduction of unsaturated species. Cheap and air-stable boric acid is shown to be a good precatalyst for BH3 hydroboration of esters and carbonates.![]()
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Affiliation(s)
- Julien Légaré Lavergne
- Département de Chimie, Université Laval 1045 Avenue de la Médecine Québec G1V 0A6 Québec Canada
| | - Hoang-Minh To
- Département de Chimie, Université Laval 1045 Avenue de la Médecine Québec G1V 0A6 Québec Canada
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15
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Benn K, Nicholson K, Langer T, Thomas SP. A boron-nitrogen transborylation enabled, borane-catalysed reductive cyanation of enones. Chem Commun (Camb) 2021; 57:9406-9409. [PMID: 34528968 DOI: 10.1039/d1cc03649a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cyanation offers a simple method for the introduction of a nitrile group into organic molecules and an orthogonal route for the installation of a wide array of functional groups using simple transformations. Cyanation methods are dominated by transition metal catalysis and the use of hydrogen cyanide gas. Here, the electrophilic cyanation of enones was achieved using a main-group catalyst and a non-toxic, electrophilic cyanide source. This protocol was applied across a broad substrate scope including those containing reducible functional groups. Mechanistic studies indicated an amino-borane intermediate which underwent B-N transborylation (B-N/B-H exchange) to achieve catalytic turnover.
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Affiliation(s)
- Kieran Benn
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, UK.
| | - Kieran Nicholson
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, UK.
| | - Thomas Langer
- Pharmaceutical Technology & Development, Chemicals Development U.K., AstraZeneca, Macclesfield SK10 2NA, UK
| | - Stephen P Thomas
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, UK.
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16
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Willcox DR, De Rosa DM, Howley J, Levy A, Steven A, Nichol GS, Morrison CA, Cowley MJ, Thomas SP. Aluminium‐Catalyzed C(sp)−H Borylation of Alkynes. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Dominic R. Willcox
- EaStCHEM School of Chemistry University of Edinburgh Joseph Black Building, David Brewster Road Edinburgh EH9 3FJ UK
| | - Daniel M. De Rosa
- EaStCHEM School of Chemistry University of Edinburgh Joseph Black Building, David Brewster Road Edinburgh EH9 3FJ UK
| | - Jack Howley
- EaStCHEM School of Chemistry University of Edinburgh Joseph Black Building, David Brewster Road Edinburgh EH9 3FJ UK
| | - Abigail Levy
- EaStCHEM School of Chemistry University of Edinburgh Joseph Black Building, David Brewster Road Edinburgh EH9 3FJ UK
| | - Alan Steven
- AstraZeneca Pharmaceutical Technology and Development Macclesfield Campus Cheshire SK10 2NA UK
| | - Gary S. Nichol
- EaStCHEM School of Chemistry University of Edinburgh Joseph Black Building, David Brewster Road Edinburgh EH9 3FJ UK
| | - Carole A. Morrison
- EaStCHEM School of Chemistry University of Edinburgh Joseph Black Building, David Brewster Road Edinburgh EH9 3FJ UK
| | - Michael J. Cowley
- EaStCHEM School of Chemistry University of Edinburgh Joseph Black Building, David Brewster Road Edinburgh EH9 3FJ UK
| | - Stephen P. Thomas
- EaStCHEM School of Chemistry University of Edinburgh Joseph Black Building, David Brewster Road Edinburgh EH9 3FJ UK
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Willcox DR, De Rosa DM, Howley J, Levy A, Steven A, Nichol GS, Morrison CA, Cowley MJ, Thomas SP. Aluminium-Catalyzed C(sp)-H Borylation of Alkynes. Angew Chem Int Ed Engl 2021; 60:20672-20677. [PMID: 34107161 PMCID: PMC8518654 DOI: 10.1002/anie.202106216] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Indexed: 12/31/2022]
Abstract
Historically used in stoichiometric hydroalumination chemistry, recent advances have transformed aluminium hydrides into versatile catalysts for the hydroboration of unsaturated multiple bonds. This catalytic ability is founded on the defining reactivity of aluminium hydrides with alkynes and alkenes: 1,2‐hydroalumination of the unsaturated π‐system. This manuscript reports the aluminium hydride catalyzed dehydroborylation of terminal alkynes. A tethered intramolecular amine ligand controls reactivity at the aluminium hydride centre, switching off hydroalumination and instead enabling selective reactions at the alkyne C−H σ‐bond. Chemoselective C−H borylation was observed across a series of aryl‐ and alkyl‐substituted alkynes (21 examples). On the basis of kinetic and density functional theory studies, a mechanism in which C−H borylation proceeds by σ‐bond metathesis between pinacolborane (HBpin) and alkynyl aluminium intermediates is proposed.
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Affiliation(s)
- Dominic R Willcox
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Daniel M De Rosa
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Jack Howley
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Abigail Levy
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Alan Steven
- AstraZeneca Pharmaceutical Technology and Development, Macclesfield Campus, Cheshire, SK10 2NA, UK
| | - Gary S Nichol
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Carole A Morrison
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Michael J Cowley
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Stephen P Thomas
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
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Nicholson K, Langer T, Thomas SP. Borane-Catalyzed, Chemoselective Reduction and Hydrofunctionalization of Enones Enabled by B-O Transborylation. Org Lett 2021; 23:2498-2504. [PMID: 33724859 DOI: 10.1021/acs.orglett.1c00446] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The use of stoichiometric organoborane reductants in organic synthesis is well established. Here these reagents have been rendered catalytic through an isodesmic B-O/B-H transborylation applied in the borane-catalyzed, chemoselective alkene reduction and formal hydrofunctionalization of enones. The reaction was found to proceed by a 1,4-hydroboration of the enone and B-O/B-H transborylation with HBpin, enabling catalyst turnover. Single-turnover and isotopic labeling experiments supported the proposed mechanism of catalysis with 1,4-hydroboration and B-O/B-H transborylation as key steps.
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Affiliation(s)
- Kieran Nicholson
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Thomas Langer
- Pharmaceutical Technology & Development, Chemicals Development U.K., AstraZeneca, Silk Road, Macclesfield SK10 2NA, United Kingdom
| | - Stephen P Thomas
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
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Willcox DR, Nichol GS, Thomas SP. Borane-Catalyzed C(sp3)–F Bond Arylation and Esterification Enabled by Transborylation. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00282] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Dominic R. Willcox
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh, EH9 3FJ, U.K
| | - Gary S. Nichol
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh, EH9 3FJ, U.K
| | - Stephen P. Thomas
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh, EH9 3FJ, U.K
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