Article
Chemistry, Physical
Vincent Desrosiers, Samantha M. Knight, Frederic-Georges Fontaine
Summary: Alkenyl boronates are commonly used reagents in organic synthesis for the formation of crucial bonds. This study introduces a metal-free isodesmic borylation strategy for the C-H borylation of electron-rich olefins, using 2-mercaptoimidazole compounds as efficient catalysts. The borylated compounds can be further functionalized in one-pot transformations, demonstrating the versatility and tolerance of this method.
Article
Chemistry, Physical
Joshua S. Sapsford, Daniel Csokas, Roland C. Turnell-Ritson, Liam A. Parkin, Andrew D. Crawford, Imre Papai, Andrew E. Ashley
Summary: The newly synthesized compound iPr(3)SnNTf(2) exhibits stronger Lewis acid properties compared to previously studied compounds, enabling faster hydrogen activation and catalytic hydrolysis of ester bonds. The reaction outcome is influenced by the steric and electronic properties of the substrate, with computational studies revealing differences in the reaction mechanisms between different ester substrates.
Review
Chemistry, Organic
Frederic-Georges Fontaine, Vincent Desrosiers
Summary: In recent years, the chemistry of frustrated Lewis pairs (FLP) has enabled various transformations, particularly in C-H bond activation and borylation reactions. A comparison is made between FLP borylation chemistry and early borylation methodologies. The mechanism of C-H borylation using inter- and intramolecular Lewis pairs, along with some applications, is presented.
SYNTHESIS-STUTTGART
(2021)
Article
Chemistry, Physical
Matthew E. Grundy, Lia Sotorrios, Milan Kumar Bisai, Kang Yuan, Stuart A. Macgregor, Michael J. Ingleson
Summary: [(NacNac)Zn(DMT)][B(C6F5)4], 1, was synthesized and demonstrated as an efficient catalyst for the C-H borylation of (hetero)arenes using catecholborane. Computational studies revealed a plausible mechanism involving displacement of DMT by CatBH and subsequent steps including dehydrocoupling and displacement of CatBAr. The research also provided insight into a possible decomposition pathway of the catalyst involving boron to zinc hydride transfer.
Article
Chemistry, Physical
Matthew E. Grundy, Lia Sotorrios, Milan Kumar Bisai, Kang Yuan, Stuart A. Macgregor, Michael J. Ingleson
Summary: This article reports the synthesis of (NacNac)Zn(DMT) complex via two different routes and its use as a catalyst for C-H borylation. Computational studies elucidated the reaction mechanism and revealed the influence of the electronic and steric parameters of the base on the catalyst's performance.
Article
Chemistry, Multidisciplinary
Xinyue Tan, Huadong Wang
Summary: The concept of frustrated Lewis pair (FLP) chemistry has become a rich and fruitful research area, contributing significantly to the revival of main group chemistry. The design of catalytic systems based on the FLP concept has been successfully applied to organic synthesis and polymer chemistry.
CHINESE JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Tongtong Wang, Maotong Xu, Andrew R. Jupp, Zheng-Wang Qu, Stefan Grimme, Douglas W. Stephan
Summary: The frustrated Lewis pair (FLP) derived from 2,6-lutidine and B(C6F5)(3) has been shown to mediate the catalytic hydrogenation of CO2, with control over product nature through careful selection of silylhalide and solvent. This metal-free catalysis offers pathways to selectively form specific compounds under mild conditions, as elucidated by DFT studies on the mechanism and selectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Lucas Wickemeyer, Israel Fernandez, Beate Neumann, Hans-Georg Stammler, Norbert W. Mitzel
Summary: The oxygen-bridged frustrated Lewis pairs (FLPs) underwent selective complexation with azobenzene under UV irradiation. The adduct of the second FLP was stable, while the adduct of the first FLP showed a [3,3]-rearrangement resembling ortho-benzidine. Similar rearrangements were observed with different para-substituted azobenzenes and di(2-naphthyl)diazene, but not with ortho-methylated azo compounds. The characterization of all adducts was done by multinuclear NMR spectroscopy and elemental analyses, and the rearrangement mechanism was explored using quantum-chemical calculations.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Thaddaeus Thorwart, Deborah Hartmann, Lutz Greb
Summary: In this study, a novel Lewis acid was reported and successfully applied in dihydrogen activation, which has been elusive for non-planar Lewis acid. This research result is important for understanding the mechanism of FLP reactions.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Physical
Yao-Bing Huang, Feng Gu, Bin Hu, Ke-Ming Li, Zhong-Ming Xu, Jinyue Luo, Qiang Lu
Summary: In this study, a flexible approach to fabricate borane-nitrogen containing phenolic organic microspheres (BNPs) was reported, serving as a new, moisture-tolerant, and bench-stable heterogeneous FLP catalyst for molecular hydrogen activation for the selective hydrogenation of structurally diverse terminal alkynes to the respective alkenes. Mechanistic studies further revealed a heterolytic hydrogen splitting process, in which the in situ formation of active hydroborane species was involved. Given the wide applicability of FLP, our protocol paves the way for advancing BNPs as a new member of the heterogeneous FLP family for catalysis.
CHEMISTRY OF MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Subrata Hazra, Somenath Mahato, Kanak Kanti Das, Santanu Panda
Summary: This article summarizes the current research status and methods of transition-metal-free synthesis of heteroaryl boronic acids and esters. The transition-metal-free synthesis methods are environmentally friendly, economically advantageous, and have replaced transition-metal-based synthesis methods.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Rachana Meena, Shashank Shekhar, Shabina B. Ansari, Ashwani Tiwari, Jhajan Lal, Damodara N. Reddy
Summary: The discovery of milder and robust strategies for introducing organoboronates in peptides is currently not well developed. This study demonstrates an efficient method for site-selective sp(2)-C7-H borylation of tryptophan using BBr3 directed by a pivaloyl group, under metal-free conditions. The versatility of this approach allows for gram-scale synthesis and modification of C7-borylated N-Phth-Trp(N-Piv)(C7-BPin)-OMe into various C7-substituted derivatives. Furthermore, this strategy enables peptide elongation and late-stage borylation of peptides, natural product Brevianamide F, and drug Oglufanide.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Yin Zhang, Songbo Chen, Abdullah M. Al-Enizi, Ayman Nafady, Zhiyong Tang, Shengqian Ma
Summary: In this study, a strategy for integrating molecular chiral frustrated Lewis pair (CFLP) with porous metal-organic framework (MOF) was proposed and the catalyst CFLP@MOF was successfully constructed, which enables heterogeneous asymmetric hydrogenation. The developed CFLP@MOF catalyst exhibits high activity/enantio-selectivity and excellent recyclability/regenerability, providing a new avenue for the design and preparation of advanced catalysts for asymmetric catalysis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Xiongfei Zheng, Ili Zulkifly, Andreas Heilmann, Caitilin McManus, Simon Aldridge
Summary: Two BNB-type frustrated Lewis pairs with different B-bound fluoroaryl groups are capable of capturing gaseous CO reversibly at/above room temperature, with migration of an aryl substituent to the electrophilic carbon of the CO guest. This reversibility allows for release of captured carbon monoxide in the temperature range 40-70 degrees C, enabling potential CO sensing based on color changes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Chamila Manankandayalage, Daniel K. Unruh, Clemens Krempner
Summary: The intramolecular inverse frustrated Lewis pairs (FLPs) with weakly Lewis acidic boryl and strongly basic guanidino moieties were synthesized and characterized, demonstrating their capability to activate small molecules. These novel FLPs show promising potential in diverse chemical transformations.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Organic
Arumugam Jayaraman, Henry Powell-Davies, Frederic-Georges Fontaine
Article
Nanoscience & Nanotechnology
Yimu Hu, Luis C. Misal Castro, Elisabeth Drouin, Justyna Florek, Hanspeter Kaehlig, Dominic Lariviere, Freddy Kleitz, Frederic-Georges Fontaine
ACS APPLIED MATERIALS & INTERFACES
(2019)
Article
Chemistry, Multidisciplinary
Etienne Rochette, Vincent Desrosiers, Yashar Soltani, Frederic-Georges Fontaine
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2019)
Article
Chemistry, Multidisciplinary
Yudha P. Budiman, Arumugam Jayaraman, Alexandra Friedrich, Florian Kerner, Udo Radius, Todd B. Marder
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2020)
Article
Chemistry, Multidisciplinary
Wei Lu, Arumugam Jayaraman, Felipe Fantuzzi, Rian D. Dewhurst, Marcel Haerterich, Maximilian Dietz, Stephan Hagspiel, Ivo Krummenacher, Kai Hammond, Jingjing Cui, Holger Braunschweig
Summary: A one-pot synthesis of a CAAC-stabilized, unsymmetrical, cyclic diborene was achieved through consecutive two-electron reduction steps, resulting in a diborene with a smaller HOMO-LUMO gap. Complexation with [AuCl(PCy3)] led to two diborene-Au-I pi complexes, while reactions with different reagents led to cleavage of various bonds, and thermal rearrangement gave rise to an electron-rich cyclic alkylideneborane that easily coordinated to Ag-I.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Stephanie Kachel, Arumugam Jayaraman, Alexander Okorn, Ivo Krummenacher, Regina Drescher, Carina Brunecker, Sonja Fuchs, Merlin Hess, Tom E. Stennett, Holger Braunschweig
Summary: In this study, we demonstrate that the azide-alkyne cycloaddition between a diaminoalkyne and aryl azides can lead to the formation of 3H-indoles under mild, uncatalysed conditions. Computations reveal that N-2 extrusion from isolable triazoles is readily achieved, generating imino carbenes that undergo intramolecular aryl C-H bond activation and subsequent conversion to 3H-indoles.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Sonja Fuchs, Arumugam Jayaraman, Ivo Krummenacher, Laura Haley, Marta Bastovanovic, Maximilian Fest, Krzysztof Radacki, Holger Helten, Holger Braunschweig
Summary: We found that the outcome of the tin-boron exchange reaction depends on the steric bulk of the aryl substituent of the borane reagent, resulting in the formation of either boroles or large diboracycles. NMR spectroscopic studies showed that the two products can reversibly interconvert in solution, and density functional theory calculations revealed boroles to be intermediates in the formation of the diboracyclic products.
Article
Chemistry, Multidisciplinary
Ramapada Dolai, Rahul Kumar, Benedict J. Elvers, Pradeep Kumar Pal, Benson Joseph, Rina Sikari, Mithilesh Kumar Nayak, Avijit Maiti, Tejender Singh, Nicolas Chrysochos, Arumugam Jayaraman, Ivo Krummenacher, Jagannath Mondal, U. Deva Priyakumar, Holger Braunschweig, Cem B. Yildiz, Carola Schulzke, Anukul Jana
Summary: A new type of carbodicarbene (CDC) with two different classes of carbenes has been reported, which shows promising potential as organic electron donors and n-dopants. These compounds exhibit notable redox properties and can form carbon-carbon sigma bonds through reactions with [NO][SbF6].
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Debabrata Dhara, Arumugam Jayaraman, Marcel Haerterich, Merle Arrowsmith, Malte Juergensen, Maximilian Michel, Holger Braunschweig
Summary: The reduction of sterically encumbered terphenyl-substituted aluminium diiodide produced a masked dialumene stabilized by [2+2] cycloaddition with an aromatic group. In situ generation of a carbene-stabilized arylalumylene, trapped by an alkyne, led to the formation of an aluminacyclopropene or a C-H activated product, depending on the alkyne's steric bulk. The masked dialumene also underwent intramolecular cycloreversion and dissociation into alumylene fragments, which reacted with various organic azides to yield monomeric or dimeric iminoalanes, depending on the azide substituent's sterics. The thermodynamics of monomeric and dimeric iminoalane formation were investigated by theoretical calculations.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Alexander Okorn, Arumugam Jayaraman, Lukas Englert, Merle Arrowsmith, Theresa Swoboda, Jeanette Weigelt, Carina Brunecker, Merlin Hess, Anna Lamprecht, Carsten Lenczyk, Maximilian Rang, Holger Braunschweig
Summary: The absence of a second ortho-substituent on the boron-bound aryl rings causes the decomposition of the diborane(4) precursors during the reaction process. By reducing the precursors, the desired products can be obtained. The low-lying pi* molecular orbitals located on the PAH substituents lead to a relatively small HOMO-LUMO gap. The hydrogenation reactions of the PAH-substituted diborenes proceed via a different pathway compared to the dimesityldiborene.
Article
Chemistry, Multidisciplinary
Debabrata Dhara, Arumugam Jayaraman, Marcel Haerterich, Rian D. Dewhurst, Holger Braunschweig
Summary: In this study, a stable base-free arylalumylene with a sterically encumbered terphenyl substituent has been reported. However, attempts to form a base-stabilised arylalumylene with a relatively small terphenyl substituent and an N-heterocyclic carbene base resulted in a masked dialumene stabilized by one peripheral aromatic group. Interestingly, further examination revealed that both this masked dialumene and its transient form decouple into the desired base-stabilised arylalumylene under different conditions. Computational insights on the dissociation of the dialumene and the mechanism of arene deconstruction by alumylene were also obtained.
Article
Chemistry, Multidisciplinary
Tom E. Stennett, Arumugam Jayaraman, Tobias Brueckner, Lea Schneider, Holger Braunschweig
Article
Chemistry, Inorganic & Nuclear
Nicolas Bouchard, Frederic-Georges Fontaine
DALTON TRANSACTIONS
(2019)
Article
Chemistry, Physical
Yimu Hu, Simon Giret, Rafael Meinusch, Jongho Han, Frederic-Georges Fontaine, Freddy Kleitz, Dominic Lariviere
JOURNAL OF MATERIALS CHEMISTRY A
(2019)