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Bedford-Type Palladacycle Catalyzed Miyaura-Borylation of Aryl Halides with Tetrahydroxydiboron in Water

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Bedford-Type Palladacycle Catalyzed Miyaura-Borylation of Aryl Halides with Tetrahydroxydiboron in Water Bedford-type palladacycle catalyzed Miyaura-borylation of aryl halides with tetrahydroxydiboron in water Item Type Article Authors Zernickel, Anna; du, weiyuan; Ghorpade, Seema; Sawant, Dinesh; Makki, Arwa; Sekar, Nagaiyan; Eppinger, Jörg Citation Zernickel A, Du W, Ghorpade S, Sawant DN, Makki AA, et al. (2018) Bedford-type palladacycle catalyzed Miyaura-borylation of aryl halides with tetrahydroxydiboron in water. The Journal of Organic Chemistry. Available: http://dx.doi.org/10.1021/ acs.joc.7b02771. Eprint version Post-print DOI 10.1021/acs.joc.7b02771 Publisher American Chemical Society (ACS) Journal The Journal of Organic Chemistry Rights This document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Organic Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/10.1021/ acs.joc.7b02771. Download date 28/09/2021 03:17:04 Link to Item http://hdl.handle.net/10754/626747 Subscriber access provided by King Abdullah University of Science and Technology Library Article Bedford-type palladacycle catalyzed Miyaura-borylation of aryl halides with tetrahydroxydiboron in water Anna Zernickel, Weiyuan Du, Seema Ghorpade, Dinesh Nanaji Sawant, Arwa A. Makki, Nagaiyan Sekar, and Jörg Eppinger J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.7b02771 • Publication Date (Web): 09 Jan 2018 Downloaded from http://pubs.acs.org on January 14, 2018 Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts. The Journal of Organic Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties. Page 1 of 25 The Journal of Organic Chemistry 1 2 3 Bedford-type palladacycle catalyzed Miyaura-borylation of aryl halides with 4 tetrahydroxydiboron in water 5 6 Anna Zernickel†, Weiyuan Du†, Seema A. Ghorpade†,‡, Dinesh N. Sawant†,§*, † ‡ †* 7 Arwa A. Makki , Nagaiyan Sekar and Jörg Eppinger 8 † King Abdullah University of Science and Technology (KAUST), Division of Physical Sciences & Engineering, 9 KAUST Catalysis Center (KCC), Thuwal 23955-6900, Saudi Arabia. 10 11 ‡Department of Dyestuff Technology, Institute of Chemical Technology (Deemed University), N. Parekh Marg, 12 Matunga, Mumbai-400019, Maharashtra, India 13 14 §Current address (D.N.S): Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 15 29a, 18059 Rostock, Germany 16 17 E-mail: [email protected] (J. E.); [email protected] (D.N. S), [email protected] 18 19 Abstract: 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 A mild aqueous protocol for palladium catalyzed Miyaura borylation of aryl iodides, aryl 38 39 bromides and aryl chlorides with tetrahydroxydiboron (BBA) as a borylating agent is 40 41 developed. The developed methodology requires low catalyst loading of Bedford-type 42 palladacycle catalyst (0.05 mol %) and works best under mild reaction conditions at 40 °C in 43 44 short time of 6 hours in water. In addition, our studies show that for Miyaura borylation using 45 BBA in aqueous condition, maintaining a neutral reaction pH is very important for 46 47 reproducibility and higher yields of corresponding borylated products. Moreover, our protocol 48 49 is applicable for a broad range of aryl halides, corresponding borylated products are obtained 50 in excellent yields up to 93% with 29 examples demonstrating its broad utility and functional 51 52 group tolerance. 53 54 55 Keywords: Miyaura-borylation, Palladacycle, Tetrahydroxydiboron, Arylboronic acids 56 57 58 59 60 ACS Paragon Plus Environment The Journal of Organic Chemistry Page 2 of 25 1 2 3 Introduction 4 Arylboronic acids provide a unique combination of stability, mild Lewis acidity, low 5 6 7 toxicity and distinct reactivity profile, therefore a tremendous interest in synthesis and 8 1 9 applications of arylboronic acids, and their corresponding intermediates exists. Notably 10 11 arylboronic acids and their corresponding esters and trifluoroborates are widely explored as a 12 13 substrate for numerous organic transformations. In last decade arylboronic acids are well 14 15 explored for various cross-coupling reactions, such as Suzuki-Miyaura coupling, the Hosomi- 16 17 Sakurai allylation2 and the oxidative Chan-Lam coupling.3 Moreover, other applications 18 19 includes 1,4-additions4 and 1,2-additions5 of boronic acids to Michael acceptors and 20 21 6 22 aldehydes, e.g. the Petasis borono-Mannich reaction . Particularly in bioorganic and 23 24 medicinal chemistry, arylboronic acids serve as valuable tool for a broad range of applications 25 26 including sensors molecules,7 enzyme inhibitors or in vivo alteration of cellular functions.8 27 28 Recently many catalytic protocols for amide or peptide synthesis have been reported using 29 30 various arylboronic acid derivatives as catalysts.9 Therefore due to their wide applications in 31 32 synthetic chemistry, as well as in biology, there are numerous methods reported for the 33 34 35 synthesis of arylboronic acids (Scheme 1). 36 37 38 39 40 41 42 43 44 45 46 47 48 49 Scheme 1. Metal based borylation protocols 50 51 52 Traditionally arylboronic acids were prepared by a metal-halogen exchange approach using 53 10 11 54 stoichiometric amount of organolithium or Grignard-reagents , but offers only limited 55 56 tolerance to functional groups and also generates stoichiometric amount of toxic waste 57 58 59 60 ACS Paragon Plus Environment Page 3 of 25 The Journal of Organic Chemistry 1 2 12 3 (Scheme 1, A). To address these issues several research groups, including those of Smith, 4 13 14 15 5 Hartwig, Miyaura and Marder have recently reported efficient catalytic borylation 6 7 protocols by C-H activation of aromatic compounds using iridium or rhodium catalysts, but 8 9 regioselectivity is determined by steric and electronic factors, which represents a major 10 11 drawback (Scheme 1, B). Currently, transition-metal-catalyzed Miyaura borylation of aryl 12 13 16 14 halides therefore provide the most versatile access to arylboronic acids, as it combines high 15 16 functional group tolerance and selectivity. Yet, most of these reported catalytic borylation 17 18 methods typically require the use of expensive pinacolato-boron precursors. In addition, 19 20 reaction of pinacolato-boron with aryl halide gives arylboronic ester as a product instead of 21 22 arylboronic acid, necessitating an additional deprotection step which ultimately generates 23 24 additional stoichiometric amount of waste (Scheme 1, C). In this regard Molander et al. 25 26 27 reported a palladiumcatalyzed borylation protocol, which employed economical and greener 28 29 bis-boronic acid (BBA) also known as tetrahydroxydiboron as a boron source in ethanol as a 30 31 solvent. The resulting diethyl boronic esters converted in situ into the more stable 32 33 trifluoroborates or even directly applied in cross-coupling reactions (Scheme 1, D).17 This 34 35 represents a major step towards more atom economic and sustainable synthesis of organo- 36 37 boronic acids. Thereafter many other transition metals based catalytic protocols were 38 39 reported for borylation of aryl halides.18 Recently nice progress has been made in 40 41 18b,19 18b,20 42 photoinduced borylation , as well as organo-catalytic borylation protocols. However 43 44 overall most of the reported borylation protocols requires use of toxic and environmental 45 46 hazardous organic solvents, high catalyst loading, higher temperature (reflux or >80 oC) and 47 48 longer reaction time, which limits its wide applications. Nevertheless, it would be more 49 50 economically and industrially appealing to develop a water based, greener borylation protocol 51 52 for direct synthesis of aryl boronic acids using tetrahydroxydiboron (BBA) with lowest 53 54 21 55 possible catalyst loading, in shorter time, under mild reaction conditions. Particularly 56 57 compared to toxic organic solvents, water is safe to handle, greener, economically and 58 59 60 ACS Paragon Plus Environment The Journal of Organic Chemistry Page 4 of 25 1 2 3 environmentally friendly solvent. Therefore, in the last decade there is growing interest for 4 5 water based cross-coupling reactions and many water based catalytic protocols have been 6 7 reported particularly with major contributions by Beller,22 Plenio,23 Shaughnessy,24 8 9 Leadbeater25 and Lipshutz.26 However the water based protocol under mild reaction 10 11 conditions for a Miyaura-borylation is rarely explored.
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