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Iqbal SA, Uzelac M, Nawaz I, Wang Z, Jones TH, Yuan K, Millet CRP, Nichol GS, Chotana GA, Ingleson MJ. Amides as modifiable directing groups in electrophilic borylation. Chem Sci 2023; 14:3865-3872. [PMID: 37035693 PMCID: PMC10074396 DOI: 10.1039/d2sc06483a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 03/14/2023] [Indexed: 03/17/2023] Open
Abstract
Amide directed C-H borylation using ≥two equiv. of BBr3 forms borenium cations containing a R2N(R')C[double bond, length as m-dash]O→B(Ar)Br unit which has significant Lewis acidity at the carbonyl carbon. This enables reduction of the amide unit to an amine using hydrosilanes. This approach can be applied sequentially in a one-pot electrophilic borylation-reduction process, which for phenyl-acetylamides generates ortho borylated compounds that can be directly oxidised to the 2-(2-aminoethyl)-phenol. Other substrates amenable to the C-H borylation-reduction sequence include mono and diamino-arenes and carbazoles. This represents a simple method to make borylated molecules that would be convoluted to access otherwise (e.g. N-octyl-1-BPin-carbazole). Substituent variation is tolerated at boron as well as in the amide unit, with diarylborenium cations also amenable to reduction. This enables a double C-H borylation-reduction-hydrolysis sequence to access B,N-polycyclic aromatic hydrocarbons (PAHs), including an example where both the boron and nitrogen centres contain functionalisable handles (N-H and B-OH). This method is therefore a useful addition to the metal-free borylation toolbox for accessing useful intermediates (ArylBPin) and novel B,N-PAHs.
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Affiliation(s)
- Saqib A Iqbal
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Marina Uzelac
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Ismat Nawaz
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
- Department of Chemistry and Chemical Engineering, Lahore University of Management Sciences Lahore 54792 Pakistan
| | - Zhongxing Wang
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - T Harri Jones
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Kang Yuan
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Clement R P Millet
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Gary S Nichol
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Ghayoor Abbas Chotana
- Department of Chemistry and Chemical Engineering, Lahore University of Management Sciences Lahore 54792 Pakistan
| | - Michael J Ingleson
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
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Iqbal SA, Millet CRP, Pahl J, Yuan K, Ingleson MJ. Two Directing Groups Used for Metal Catalysed Meta-C-H Functionalisation Only Effect Ortho Electrophilic C-H Borylation. European J Org Chem 2022; 2022:e202200901. [PMID: 36636663 PMCID: PMC9828458 DOI: 10.1002/ejoc.202200901] [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: 07/26/2022] [Revised: 10/20/2022] [Indexed: 01/16/2023]
Abstract
Two templates used in meta-directed C-H functionalisation under metal catalysis do not direct meta-C-H borylation under electrophilic borylation conditions. Using BCl3 only Lewis adduct formation with Lewis basic sites in the template is observed. While combining BBr3 and the template containing an amide linker only led to amide directed ortho C-H borylation, with no pyridyl directed meta borylation. The amide directed borylation is selective for the ortho borylation of the aniline derived unit in the template, with no ortho borylation of the phenylacetyl ring - which would also form a six membered boracycle - observed. In the absence of other aromatics amide directed ortho borylation on to phenylacetyl rings can be achieved. The absence of meta-borylation using two templates indicates a higher barrier to pyridyl directed meta borylation relative to amide directed ortho borylation and suggests that bespoke templates for enabling meta-directed electrophilic borylation may be required.
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Affiliation(s)
- Saqib A Iqbal
- EaStCHEM School of Chemistry University of Edinburgh Edinburgh EH9 3FJ UK
| | - Clement R P Millet
- EaStCHEM School of Chemistry University of Edinburgh Edinburgh EH9 3FJ UK
| | - Jürgen Pahl
- EaStCHEM School of Chemistry University of Edinburgh Edinburgh EH9 3FJ UK
| | - Kang Yuan
- EaStCHEM School of Chemistry University of Edinburgh Edinburgh EH9 3FJ UK
| | - Michael J Ingleson
- EaStCHEM School of Chemistry University of Edinburgh Edinburgh EH9 3FJ UK
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Recent Progress on Synthesis of N, N'-Chelate Organoboron Derivatives. Molecules 2021; 26:molecules26051401. [PMID: 33807680 PMCID: PMC7961668 DOI: 10.3390/molecules26051401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 02/07/2023] Open
Abstract
N,N′-chelate organoboron compounds have been successfully applied in bioimaging, organic light-emitting diodes (OLEDs), functional polymer, photocatalyst, electroluminescent (EL) devices, and other science and technology areas. However, the concise and efficient synthetic methods become more and more significant for material science, biomedical research, or other practical science. Here, we summarized the organoboron-N,N′-chelate derivatives and showed the different routes of their syntheses. Traditional methods to synthesize N,N′-chelate organoboron compounds were mainly using bidentate ligand containing nitrogen reacting with trivalent boron reagents. In this review, we described a series of bidentate ligands, such as bipyridine, 2-(pyridin-2-yl)-1H-indole, 2-(5-methyl-1H-pyrrol-2-yl)quinoline, N-(quinolin-8-yl)acetamide, 1,10-phenanthroline, and diketopyrrolopyrrole (DPP).
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Yoshino J, Hirono Y, Akahane R, Higuchi H, Hayashi N. Effects of π-conjugation on the solid-state photoresponsive coloring behavior of bipyridine-boronium complexes. Photochem Photobiol Sci 2020; 19:1517-1521. [PMID: 33047774 DOI: 10.1039/d0pp00296h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Solid-state photoinduced coloring of boronium complexes consisting of 9-borabicyclononane and 2,2'-bipyridine with π-conjugated substituents at the 4,4'- or 5,5'-positions was investigated. The substitution position affected the highest occupied molecular orbital distribution and determined the coloring capability. The 4,4'-substituted complexes exhibited coloration upon irradiation, whereas most of the 5,5'-substituted complexes did not.
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Affiliation(s)
- Junro Yoshino
- Faculty of Science, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan. and Department of Chemistry, Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Yoshito Hirono
- Department of Chemistry, Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Ryota Akahane
- Department of Chemistry, Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Hiroyuki Higuchi
- Department of Chemistry, Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Naoto Hayashi
- Faculty of Science, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan. and Department of Chemistry, Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
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Cui C, Heilmann-Brohl J, Sánchez Perucha A, Thomson MD, Roskos HG, Wagner M, Jäkle F. Redox-Active Ferrocenylboronium Polyelectrolytes with Main Chain Charge-Transfer Structure. Macromolecules 2010. [DOI: 10.1021/ma100440g] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chengzhong Cui
- Department of Chemistry, Rutgers University-Newark, 73 Warren Street, Newark, New Jersey 07102
| | - Julia Heilmann-Brohl
- Institut für Anorganische und Analytische Chemie, Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, D-60438 Frankfurt am Main, Germany
| | - Alejandro Sánchez Perucha
- Institut für Anorganische und Analytische Chemie, Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, D-60438 Frankfurt am Main, Germany
| | - Mark D. Thomson
- Physikalisches Institut, Robert-Mayer-Strasse 2-4, Johann Wolfgang Goethe-Universität Frankfurt, D-60054 Frankfurt am Main, Germany
| | - Hartmut G. Roskos
- Physikalisches Institut, Robert-Mayer-Strasse 2-4, Johann Wolfgang Goethe-Universität Frankfurt, D-60054 Frankfurt am Main, Germany
| | - Matthias Wagner
- Institut für Anorganische und Analytische Chemie, Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, D-60438 Frankfurt am Main, Germany
| | - Frieder Jäkle
- Department of Chemistry, Rutgers University-Newark, 73 Warren Street, Newark, New Jersey 07102
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Newkome GR, Shreiner CD. Poly(amidoamine), polypropylenimine, and related dendrimers and dendrons possessing different 1→2 branching motifs: An overview of the divergent procedures. POLYMER 2008. [DOI: 10.1016/j.polymer.2007.10.021] [Citation(s) in RCA: 313] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Weber L, Domke I, Schmidt C, Braun T, Stammler HG, Neumann B. Syntheses, structures, luminescence and electrochemistry of benzene- and biphenyl-centered bis- and tris-1,3,2-diazaboroles and -1,3,2-diazaborolidines. Dalton Trans 2006:2127-32. [PMID: 16625257 DOI: 10.1039/b514920g] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction of 1,4-bis(dibromoboryl)benzene (1a) with 2 equiv. of the diazabutadiene tBuN=CH-CH=NtBu and subsequent reduction of the obtained bis(1,3,2-diazaborolium)salt 2a with sodium amalgam afforded the 1,4-bis(1,3,2-diazaborolyl)benzene 3a. Similarly, 1,3-bis(dibromoboryl)benzene (1b), 1,3,5-tris(dibromoboryl)benzene (1c) and 4,4'-bis(dibromoboryl)biphenyl (1d) were converted into compounds 3b, 3c and 3d which contain two or three diazaborolyl substituents at the arene core. Treatment of precursors 1a,b,d with two equiv. or with three equiv. of N,N'-di-tert-butylethane-1,2-diamine in the presence of an excess of NEt3 gave rise to the diazaborolidine derivatives 4a-4d. Reaction of 1,3-bis(diiodoboryl)benzene with two equivalents of N,N'-dimethylethane-1,2-diamine in the presence of NEt3 furnished the corresponding 1,3-bis(diazaborolidinyl)benzene 4e. The novel compounds were characterized by elemental analyses and spectroscopy (1H, 13C, 11B NMR, MS). The molecular structures of 3c, 4a and 4e were eludicated by X-ray-diffraction analyses. In addition to this, the oxidative cyclovoltammograms and blue emission spectra of these novel compounds were discussed. Here, the electronic communication between boron heterocycles on the different spacer-units and the luminescence of the oligo-diazaborolylarenes were of interest.
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Affiliation(s)
- Lothar Weber
- Fakultät für Chemie der Universität Bielefeld, Universitätsstrasse 25, D-33615, Bielefeld, Germany
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