1
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Hampton AS, Hodgson DRW, McDougald G, Wang L, Sandford G. Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas. Beilstein J Org Chem 2024; 20:460-469. [PMID: 38440170 PMCID: PMC10910478 DOI: 10.3762/bjoc.20.41] [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: 11/27/2023] [Accepted: 02/15/2024] [Indexed: 03/06/2024] Open
Abstract
Solutions of 1,3-diketones and 1,3-ketoester derivatives react with fluorine to give the corresponding 2,2-difluoro-1,3-dicarbonyl derivatives in the presence of quinuclidine. Quinuclidine reacts with fluorine in situ to generate a fluoride ion that facilitates limiting enolization processes, and an electrophilic N-F fluorinating agent that is reactive towards neutral enol species.
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Affiliation(s)
- Alexander S Hampton
- Durham University, Department of Chemistry, Lower Mountjoy, South Road, Durham, DH1 3LE, UK
| | - David R W Hodgson
- Durham University, Department of Chemistry, Lower Mountjoy, South Road, Durham, DH1 3LE, UK
| | - Graham McDougald
- Syngenta, Huddersfield Manufacturing Centre, PO Box A38, Huddersfield, West Yorkshire, HD2 1FF, UK
| | - Linhua Wang
- Syngenta USA, 410 Swing Road, Greensboro, North Carolina, NC 27409, USA
| | - Graham Sandford
- Durham University, Department of Chemistry, Lower Mountjoy, South Road, Durham, DH1 3LE, UK
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2
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Luo H, Liu FZ, Liu Y, Chu Z, Yan K. Biasing Divergent Polycyclic Aromatic Hydrocarbon Oxidation Pathway by Solvent-Free Mechanochemistry. J Am Chem Soc 2023. [PMID: 37428958 DOI: 10.1021/jacs.3c00614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2023]
Abstract
Precise control in reaction selectivity is the goal in modern organic synthesis, and it has been widely studied throughout the synthetic community. In comparison, control of divergent reactivity of a given reagent under different reaction conditions is relatively less explored aspect of chemical selectivity. We herein report an unusual reaction between polycyclic aromatic hydrocarbons and periodic acid H5IO6 (1), where the product outcome is dictated by the choice of reaction conditions. That is, reactions under solution-based condition give preferentially C-H iodination products, while reactions under solvent-free mechanochemical condition provide C-H oxidation quinone products. Control experiments further indicated that the iodination product is not a reaction intermediate toward the oxidation product and vice versa. Mechanistic studies unveiled an in situ crystalline-to-crystalline phase change in 2 during ball-milling treatment, where we assigned it as a polymeric hydrogen-bond network of 1. We believe that this polymeric crystalline phase shields the more embedded electrophilic I═O group of 1 from C-H iodination and bias a divergent C-H oxidation pathway (with I═O) in the solid state. Collectively, this work demonstrates that mechanochemistry can be employed to completely switch a reaction pathway and unmask hidden reactivity of chemical reagents.
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Affiliation(s)
- Hao Luo
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Fang-Zi Liu
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Yan Liu
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Zhaoyang Chu
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - KaKing Yan
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
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3
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Hernández JG, Ardila-Fierro KJ, Barišić D, Geneste H. Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions. Beilstein J Org Chem 2022; 18:182-189. [PMID: 35233257 PMCID: PMC8848345 DOI: 10.3762/bjoc.18.20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 01/26/2022] [Indexed: 12/18/2022] Open
Abstract
In the search for versatile reagents compatible with mechanochemical techniques, in this work we studied the reactivity of N-fluorobenzenesulfonimide (NFSI) by ball milling. We corroborated that, by mechanochemistry, NFSI can engage in a variety of reactions such as fluorinations, fluorodemethylations, sulfonylations, and amidations. In comparison to the protocols reported in solution, the mechanochemical reactions were accomplished in the absence of solvents, in short reaction times, and in yields comparable to or higher than their solvent-based counterparts.
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Affiliation(s)
- José G Hernández
- Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička c. 54, 10000 Zagreb, Croatia
- current address Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Calle 70 No 52-21, Medellín, Colombia
| | - Karen J Ardila-Fierro
- Division of Materials Chemistry, Ruđer Bošković Institute, Bijenička c. 54, 10000 Zagreb, Croatia
| | - Dajana Barišić
- Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička c. 54, 10000 Zagreb, Croatia
| | - Hervé Geneste
- AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, D-67008 Ludwigshafen, Germany
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4
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Williams MTJ, Morrill LC, Browne DL. Mechanochemical Organocatalysis: Do High Enantioselectivities Contradict What We Might Expect? CHEMSUSCHEM 2022; 15:e202102157. [PMID: 34767693 PMCID: PMC9300213 DOI: 10.1002/cssc.202102157] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/09/2021] [Indexed: 05/10/2023]
Abstract
Ball mills input energy to samples by pulverising the contents of the jar. Each impact on the sample or wall of the jar results in an instantaneous transmission of energy in the form of a temperature and pressure increase (volume reduction). Conversely, enantioselective organocatalytic reactions proceed through perceived delicate and well-organised transition states. Does there exist a dichotomy in the idea of enantioselective mechanochemical organocatalysis? This Review provides a survey of the literature reporting the combination of organocatalytic reactions with mechanochemical ball milling conditions. Where possible, direct comparisons of stirred in solution, stirred neat and ball milled processes are drawn with a particular focus on control of stereoselectivity.
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Affiliation(s)
- Matthew T. J. Williams
- Cardiff Catalysis InstituteSchool of ChemistryCardiff UniversityPark PlaceCardiffCF10 3ATUK
| | - Louis C. Morrill
- Cardiff Catalysis InstituteSchool of ChemistryCardiff UniversityPark PlaceCardiffCF10 3ATUK
| | - Duncan L. Browne
- Department of Pharmaceutical and Biological ChemistrySchool of PharmacyUniversity College London29–39 Brunswick Square, BloomsburyLondonWC1N 1AXUK
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5
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Chu X, Jiang L, Lu Q, Dong J. Mechano-Biocatalytic Rapid Synthesis of 2-Amino-3-cyano-4H-pyran Derivatives. HETEROCYCLES 2022. [DOI: 10.3987/com-21-14608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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6
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Zaikin PA, Dyan OT, Elanov IR, Borodkin GI. Ionic Liquid-Assisted Grinding: An Electrophilic Fluorination Benchmark. Molecules 2021; 26:5756. [PMID: 34641300 PMCID: PMC8510021 DOI: 10.3390/molecules26195756] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 09/18/2021] [Accepted: 09/20/2021] [Indexed: 11/17/2022] Open
Abstract
We demonstrated the influence of liquid additives on the rate and selectivity of mechanochemical fluorination of aromatic and 1,3-dicarbonyl compounds with F-TEDA-BF4. Substoichiometric catalytic quantities of ionic liquids speed up the reaction. We proposed an improved protocol for ionic liquids-assisted fluorination that allows easy and efficient isolation of fluorinated products by vacuum sublimation. A careful choice of additive results in high yields of fluorinated products and low E-factor for the overall process. Here, we report a benchmarking study of various ionic liquids in comparison with representative molecular solvents. A lower viscosity of ionic liquid additive is typically associated with higher yields and a higher degree of difluorination. Ionic liquids with fluorous anions (triflate and triflimide) are shown to be the most efficient catalysts for ionic liquid-assisted grinding.
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Affiliation(s)
- Pavel A. Zaikin
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, 9 Acad. Lavrentiev Ave., 630090 Novosibirsk, Russia; (I.R.E.); (G.I.B.)
| | - Ok Ton Dyan
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, 9 Acad. Lavrentiev Ave., 630090 Novosibirsk, Russia; (I.R.E.); (G.I.B.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogov St., 630090 Novosibirsk, Russia
| | - Innokenty R. Elanov
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, 9 Acad. Lavrentiev Ave., 630090 Novosibirsk, Russia; (I.R.E.); (G.I.B.)
| | - Gennady I. Borodkin
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, 9 Acad. Lavrentiev Ave., 630090 Novosibirsk, Russia; (I.R.E.); (G.I.B.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogov St., 630090 Novosibirsk, Russia
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7
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Riley W, Jones AC, Singh K, Browne DL, Stuart AM. Accessing novel fluorinated heterocycles with the hypervalent fluoroiodane reagent by solution and mechanochemical synthesis. Chem Commun (Camb) 2021; 57:7406-7409. [PMID: 34231584 DOI: 10.1039/d1cc02587b] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new and efficient strategy for the rapid formation of novel fluorinated tetrahydropyridazines and dihydrooxazines has been developed by fluorocyclisation of β,γ-unsaturated hydrazones and oximes with the fluoroiodane reagent. Mechanochemical synthesis delivered fluorinated tetrahydropyridazines in similar excellent yields to conventional solution synthesis, whereas fluorinated dihydrooxazines were prepared in much better yields by ball-milling.
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Affiliation(s)
- William Riley
- School of Chemistry, University of Leicester, Leicester, LE1 7RH, UK.
| | - Andrew C Jones
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK
| | - Kuldip Singh
- School of Chemistry, University of Leicester, Leicester, LE1 7RH, UK.
| | | | - Alison M Stuart
- School of Chemistry, University of Leicester, Leicester, LE1 7RH, UK.
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8
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Williams MJ, Morrill LC, Browne DL. Expedient Organocatalytic Aza-Morita-Baylis-Hillman Reaction through Ball-Milling. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2020; 8:17876-17881. [PMID: 33614300 PMCID: PMC7885690 DOI: 10.1021/acssuschemeng.0c07320] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 10/19/2020] [Indexed: 05/08/2023]
Abstract
A ball-milling enabled tertiary amine catalyzed aza-Morita-Baylis-Hillman reaction is reported. The reaction process does not require solvent, has significantly shorter reaction times than previous methods and is reported on a range of imines and acrylate Michael acceptors across than 26 examples. A 12-fold scaled-up example is also reported as well as experimental comparisons to solution-based experiments and neat-stirred reactions.
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Affiliation(s)
- Matthew
T. J. Williams
- Cardiff
Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
| | - Louis C. Morrill
- Cardiff
Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
- E-mail:
| | - Duncan L. Browne
- School
of Pharmacy, University College London, 29-39 Brunswick Square, Bloomsbury, London WC1N 1AX, United Kingdom
- E-mail:
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9
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Greve E, Lindeman SV, Scartelli C, Lin L, Flaumenhaft R, Dockendorff C. Route exploration and synthesis of the reported pyridone-based PDI inhibitor STK076545. Org Biomol Chem 2020; 18:6665-6681. [PMID: 32812971 DOI: 10.1039/d0ob01205j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The enzyme protein disulfide isomerase (PDI) is essential for the correct folding of proteins and the activation of certain cell surface receptors, and is a promising target for the treatment of cancer and thrombotic conditions. A previous high-throughput screen identified the commercial compound STK076545 as a promising PDI inhibitor. To confirm its activity and support further biological studies, a resynthesis was pursued of the reported β-keto-amide with an N-alkylated pyridone at the α-position. Numerous conventional approaches were complicated by undesired fragmentations or rearrangements. However, a successful 5-step synthetic route was achieved using an aldol reaction with an α-pyridone allyl ester as a key step. An X-ray crystal structure of the final compound confirmed that the reported structure of STK076545 was achieved, however its lack of PDI activity and inconsistent spectral data suggest that the commercial structure was misassigned.
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Affiliation(s)
- Eric Greve
- Department of Chemistry, Marquette University, P.O. Box 1881, Milwaukee, WI 53201-1881, USA.
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10
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Yin J, Stark RT, Fallis IA, Browne DL. A Mechanochemical Zinc-Mediated Barbier-Type Allylation Reaction under Ball-Milling Conditions. J Org Chem 2020; 85:2347-2354. [DOI: 10.1021/acs.joc.9b02876] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- JieXiang Yin
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K
| | - Roderick T. Stark
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K
| | - Ian A. Fallis
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K
| | - Duncan L. Browne
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K
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11
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Jeong H, Lee J. 3D‐Superstructured Networks Comprising Fe‐MIL‐88A Metal‐Organic Frameworks Under Mechanochemical Conditions. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900979] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Haneul Jeong
- Haneul Jeong Blue Wind Tech Co. Ltd. 34–5 Malgeunnae‐gil Uiwang‐si Gyeonggi‐do 16072 Korea
| | - Junhyung Lee
- Junhyung Lee ECA 161 Simin‐daero, Dongan‐gu Anyang‐si Gyeonggi‐do 14048 Korea
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12
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Rozatian N, Beeby A, Ashworth IW, Sandford G, Hodgson DRW. Enolization rates control mono- versus di-fluorination of 1,3-dicarbonyl derivatives. Chem Sci 2019; 10:10318-10330. [PMID: 32110319 PMCID: PMC6979503 DOI: 10.1039/c9sc04185k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 09/16/2019] [Indexed: 12/27/2022] Open
Abstract
All rate constants for fluorination and enolization are determined.
Fluorine-containing 1,3-dicarbonyl derivatives are essential building blocks for drug discovery and manufacture. To understand the factors that determine selectivity between mono- and di-fluorination of 1,3-dicarbonyl systems, we have performed kinetic studies of keto–enol tautomerism and fluorination processes. Photoketonization of 1,3-diaryl-1,3-dicarbonyl derivatives and their 2-fluoro analogues is coupled with relaxation kinetics to determine enolization rates. Reaction additives such as water accelerate enolization processes, especially of 2-fluoro-1,3-dicarbonyl systems. Kinetic studies of enol fluorination with Selectfluor™ and NFSI reveal the quantitative effects of 2-fluorination upon enol nucleophilicity towards reagents of markedly different electrophilicity. Our findings have important implications for the synthesis of α,α-difluoroketonic compounds, providing valuable quantitative information to aid in the design of fluorination and difluorination reactions.
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Affiliation(s)
- Neshat Rozatian
- Chemistry Department , Durham University , South Road , Durham , DH1 3LE , UK .
| | - Andrew Beeby
- Chemistry Department , Durham University , South Road , Durham , DH1 3LE , UK .
| | - Ian W Ashworth
- AstraZeneca , Pharmaceutical Technology & Development , Macclesfield , SK10 2NA , UK
| | - Graham Sandford
- Chemistry Department , Durham University , South Road , Durham , DH1 3LE , UK .
| | - David R W Hodgson
- Chemistry Department , Durham University , South Road , Durham , DH1 3LE , UK .
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13
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Đud M, Briš A, Jušinski I, Gracin D, Margetić D. Mechanochemical Friedel-Crafts acylations. Beilstein J Org Chem 2019; 15:1313-1320. [PMID: 31293680 PMCID: PMC6604704 DOI: 10.3762/bjoc.15.130] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/24/2019] [Indexed: 11/26/2022] Open
Abstract
Friedel–Crafts (FC) acylation reactions were exploited in the preparation of ketone-functionalized aromatics. Environmentally more friendly, solvent-free mechanochemical reaction conditions of this industrially important reaction were developed. Reaction parameters such as FC catalyst, time, ratio of reagents and milling support were studied to establish the optimal reaction conditions. The scope of the reaction was explored by employment of different aromatic hydrocarbons in conjunction with anhydrides and acylation reagents. It was shown that certain FC-reactive aromatics could be effectively functionalized by FC acylations carried out under ball-milling conditions without the presence of a solvent. The reaction mechanism was studied by in situ Raman and ex situ IR spectroscopy.
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Affiliation(s)
- Mateja Đud
- Ruđer Bošković Institute, Bijenička cesta 54, HR-10002 Zagreb, Croatia
| | - Anamarija Briš
- Ruđer Bošković Institute, Bijenička cesta 54, HR-10002 Zagreb, Croatia
| | - Iva Jušinski
- Ruđer Bošković Institute, Bijenička cesta 54, HR-10002 Zagreb, Croatia
| | - Davor Gracin
- Ruđer Bošković Institute, Bijenička cesta 54, HR-10002 Zagreb, Croatia
| | - Davor Margetić
- Ruđer Bošković Institute, Bijenička cesta 54, HR-10002 Zagreb, Croatia
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14
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Zhou Y, You Y, Wang ZH, Zhang XM, Xu XY, Yuan WC. Organocatalyzed Enantioselective Decarboxylative Mannich Reaction of β-Ketoacids with Pyrazolinone Ketimines for the Construction of Chiral β-Amino Ketone-Pyrazolinone Derivatives. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900346] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Yang Zhou
- National Engineering Research Center of Chiral Drugs; Chengdu Institute of Organic Chemistry; Chinese Academy of Sciences; 610041 Chengdu China
- Chengdu Institute of Organic Chemistry; University of Chinese Academy of Sciences; 100049 Beijing China
| | - Yong You
- Institute for Advanced Study; Chengdu Institute of Organic Chemistry; Chengdu University; 610106 Chengdu China
| | - Zhen-Hua Wang
- Institute for Advanced Study; Chengdu Institute of Organic Chemistry; Chengdu University; 610106 Chengdu China
| | - Xiao-Mei Zhang
- National Engineering Research Center of Chiral Drugs; Chengdu Institute of Organic Chemistry; Chinese Academy of Sciences; 610041 Chengdu China
| | - Xiao-Ying Xu
- National Engineering Research Center of Chiral Drugs; Chengdu Institute of Organic Chemistry; Chinese Academy of Sciences; 610041 Chengdu China
| | - Wei-Cheng Yuan
- National Engineering Research Center of Chiral Drugs; Chengdu Institute of Organic Chemistry; Chinese Academy of Sciences; 610041 Chengdu China
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15
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Cao Q, Nicholson WI, Jones AC, Browne DL. Robust Buchwald-Hartwig amination enabled by ball-milling. Org Biomol Chem 2019; 17:1722-1726. [PMID: 30226258 DOI: 10.1039/c8ob01781f] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
An operationally simple mechanochemical method for the Pd catalysed Buchwald-Hartwig amination of arylhalides with secondary amines has been developed using a Pd PEPPSI catalyst system. The system is demonstrated on 30 substrates and applied in the context of a target synthesis. Furthermore, the performance of the reaction under aerobic conditions has been probed under traditional solution and mechanochemical conditions, the observations are discussed herein.
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Affiliation(s)
- Qun Cao
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3EQ, UK.
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16
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Mohammadiannejad K, Ranjbar-Karimi R, Haghighat F. Synthesis of new mixed-bistriarylmethanes and novel 3,4-dihydropyrimidin-2(1H)one derivatives. NEW J CHEM 2019. [DOI: 10.1039/c8nj05845h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Formylated-triarylmethanes were realized as ideal precursors for the design and synthesis of mixed-bistriarylmethanes and 3,4-dihydropyrimidin-2(1H)one-triarylmethane hybrid derivatives.
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Affiliation(s)
- Kazem Mohammadiannejad
- NMR Laboratory
- Faculty of Science
- Vali-e-Asr University of Rafsanjan
- Rafsanjan 77176
- Islamic Republic of Iran
| | - Reza Ranjbar-Karimi
- Department of Chemistry
- Vali-e-Asr University of Rafsanjan
- Rafsanjan 77176
- Islamic Republic of Iran
| | - Farzaneh Haghighat
- Department of Chemistry
- Vali-e-Asr University of Rafsanjan
- Rafsanjan 77176
- Islamic Republic of Iran
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17
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Howard JL, Brand MC, Browne DL. Switching Chemoselectivity: Using Mechanochemistry to Alter Reaction Kinetics. Angew Chem Int Ed Engl 2018; 57:16104-16108. [PMID: 30335216 PMCID: PMC6282732 DOI: 10.1002/anie.201810141] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Indexed: 11/06/2022]
Abstract
A reaction manifold has been discovered in which the chemoselectivity can be altered by switching between neat milling and liquid assisted grinding (LAG) with polar additives. After investigation of the reaction mechanism, it has been established that this switching in reaction pathway is due to the neat mechanochemical conditions exhibiting different kinetics for a key step in the transformation. This proof of concept study demonstrates that mechanochemistry can be used to trap the kinetic product of a reaction. It is envisaged that, if this concept can be successfully applied to other transformations, novel synthetic processes could be discovered and known reaction pathways perturbed or diverted.
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Affiliation(s)
- Joseph L Howard
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3EQ, UK
| | - Michael C Brand
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3EQ, UK
| | - Duncan L Browne
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3EQ, UK
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18
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Howard JL, Brand MC, Browne DL. Switching Chemoselectivity: Using Mechanochemistry to Alter Reaction Kinetics. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201810141] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Joseph L. Howard
- School of ChemistryCardiff University Main Building, Park Place Cardiff CF10 3EQ UK
| | - Michael C. Brand
- School of ChemistryCardiff University Main Building, Park Place Cardiff CF10 3EQ UK
| | - Duncan L. Browne
- School of ChemistryCardiff University Main Building, Park Place Cardiff CF10 3EQ UK
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19
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Howard JL, Cao Q, Browne DL. Mechanochemistry as an emerging tool for molecular synthesis: what can it offer? Chem Sci 2018; 9:3080-3094. [PMID: 29780455 PMCID: PMC5933221 DOI: 10.1039/c7sc05371a] [Citation(s) in RCA: 440] [Impact Index Per Article: 62.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 02/26/2018] [Indexed: 12/11/2022] Open
Abstract
Mechanochemistry is becoming more widespread as a technique for molecular synthesis with new mechanochemical reactions being discovered at increasing frequency. Whilst mechanochemical methods are solvent free and can therefore lead to improved sustainability metrics, it is more likely that the significant differences between reaction outcomes, reaction selectivities and reduced reaction times will make it a technique of interest to synthetic chemists. Herein, we provide an overview of mechanochemistry reaction examples, with 'direct' comparators to solvent based reactions, which collectively seemingly show that solid state grinding can lead to reduced reaction times, different reaction outcomes in product selectivity and in some instances different reaction products, including products not accessible in solution.
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Affiliation(s)
- Joseph L Howard
- School of Chemistry , Cardiff University , Main Building, Park Place , Cardiff , CF10 3AT , UK .
| | - Qun Cao
- School of Chemistry , Cardiff University , Main Building, Park Place , Cardiff , CF10 3AT , UK .
| | - Duncan L Browne
- School of Chemistry , Cardiff University , Main Building, Park Place , Cardiff , CF10 3AT , UK .
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