Article
Multidisciplinary Sciences
Shiran Aharon, Dan Meyerstein, Eyal Tzur, Dror Shamir, Yael Albo, Ariela Burg
Summary: This study developed a single-stage process for the entrapment of ruthenium-based catalysts using the sol-gel process, with results showing that the nature of the precursor affects pore size and catalyst activity, and matrices prepared with tetraethoxysilane at an alkaline pH exhibit a better reaction rate. This research is the first to present a one-step process simpler and faster than methods reported in the literature for catalyst entrapment by the sol-gel process under standard conditions.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Applied
Ravindra S. Phatake, Noy B. Nechmad, Ofer Reany, N. Gabriel Lemcoff
Summary: A selective ring-closing metathesis (RCM) reaction using latent sulfur chelated ruthenium iodide benzylidenes as catalysts, activated by thermal and photochemical stimuli, has been reported. This method enables the formation of large macrocycles with high yields, especially for dienes with one terminal alkene and one internal double bond. For substrates containing two internal double bonds, a sacrificial methylene donor can be used to obtain the desired products.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Physical
Charles Killeen, Jie Liu, Harmen S. S. Zijlstra, Florian Maass, James Piers, Reid Adams, Allen Oliver, J. Scott McIndoe
Summary: Ring-closing metathesis (RCM) is a versatile method for forming cyclic structural elements. Real-time analysis using electrospray ionization mass spectrometry (ESI-MS) was applied to study the RCM reaction, revealing the presence of by-products and the decomposition of the catalyst. Isomerization reactions play a significant role in affecting the yield of the desired product, especially in slow RCM reactions.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Organic
Vachiraporn Ajavakom, Potchanee Pandokrak, Sofia S. Salim, Gamal A. I. Moustafa, Richard K. Bellingham, Joseph T. Hill-Cousins, Anawat Ajavakom, Richard C. D. Brown
Summary: A ring-closing metathesis (RCM) reaction of monobrominated dienes using Grubbs II catalyst was reported, giving moderate to good yields (40-80%) of seven-membered bromoolefins. Attempts to form five-, six-, or eight-membered bromoolefins through RCM were unsuccessful, except for one example that resulted in the formation of a bromomethyl-substituted cyclohexene as a byproduct. The selected bromoolefin RCM products showed utility in Suzuki-Miyaura reactions. Vinylic halide exchange (Br -> Cl) was observed as a side reaction under RCM conditions.
Review
Chemistry, Organic
Santhosh Kumar Podiyanachari, Hassan S. Bazzi, Mohammed Al-Hashimi
Summary: Synthesis of cycloolefin-based polymers via metathesis-accompanied cyclopolymerization and tandem ring-opening/ring-closing metathesis (RO/RCM) polymerization leads to highly functional cycloolefin ring-based polymers.
CURRENT ORGANIC CHEMISTRY
(2021)
Article
Polymer Science
Mohammad Yasir, Andreas F. M. Kilbinger
Summary: Norbornene and cyclohexene show different polymerization behaviors using Grubbs' catalysts due to their varying ring strain energy levels; a sequence-selective cascade polymerization of a monomer containing both rings resulted in polymers with moderate molecular weight dispersities and good control over molecular weight.
Article
Chemistry, Multidisciplinary
Shyamasankar Mandal, Jeet Banerjee, Sougata Maity, Shital K. Chattopadhyay
Summary: A new synthetic protocol has been developed to access 7-substituted benzo[b]azepine and benzo[b]oxepine derivatives in good overall yield from appropriate aniline or phenol using three atom-economic processes sequentially. Additionally, a one-pot RCM-CM protocol has been implemented for the synthesis of benzazepine and benzoxepine derivatives.
HELVETICA CHIMICA ACTA
(2021)
Article
Chemistry, Organic
Marina Diaz-Ruiz, Aina Urbina, Nuria Llor, Joan Bosch, Mercedes Amat, Feliu Maseras
Summary: This study reports the synthesis of a marine macrolide and investigates the mechanism of a specific reaction step. The chemoselectivity is found to be controlled by thermodynamics, which is supported by theoretical calculations and experimental studies.
Article
Chemistry, Multidisciplinary
Nils Ansmann, Thaddaus Thorwart, Lutz Greb
Summary: The Lewis superacid bis(perchlorocatecholato)silane catalyzes C-O bond metathesis of alkyl ethers with high efficiency, enabling chemoselective ring contractions of macrocyclic crown ethers and unprecedented ring-closing metathesis of polyethylene glycols for polymer-selective degradation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Review
Chemistry, Multidisciplinary
Atitegeb Abera Tsedalu
Summary: Olefin metathesis is a metal-mediated C-C bond exchange reaction that is widely used in the synthesis of organic compounds, polymers, drugs, plastics, and other synthetic materials. It involves breaking the double bond of an olefin precursor to redistribute the fragments and obtain new products.
JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Saswata Gupta, Siyuan Su, Yu Zhang, Peng Liu, Donald J. Wink, Daesung Lee
Summary: Metallaaromatics are a unique class of aromatic compounds incorporating one or more transition metal elements, showing distinctive structural and theoretical interests, and serving as a novel platform for new catalyst development.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Felix Ziegler, Thomas Roider, Markus Pyschik, Christian P. Haas, Dongren Wang, Ulrich Tallarek, Michael R. Buchmeiser
Summary: The study demonstrates the efficient use of a 2(nd)-generation Hoveyda-Grubbs-type catalyst immobilized inside mesoporous silica for selective macro(mono)cyclization (MMC) of an alpha,omega-diene under spatially confined and continuous-flow conditions. By analyzing reaction mixtures through NMR and MALDI-TOF-MS, the study identifies the effects of confinement on olefin metathesis pathways and determines conditions for achieving high MMC selectivity. The research also highlights the preference for ring-closing metathesis of monomers and backbiting from dimers and trimers under confinement, leading to a high MMC selectivity of 60%.
Article
Chemistry, Multidisciplinary
Dmitry S. Belov, Gabriela Tejeda, Charlene Tsay, Konstantin V. Bukhryakov
Summary: Vanadium-based catalysts have been demonstrated to catalyze ring-closing olefin metathesis reactions by well-defined V chloride alkylidene phosphine complexes, exhibiting good functional group tolerance. The properties of the imido group and phosphine were found to play a crucial role in the stability of active intermediates.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Review
Chemistry, Multidisciplinary
Shrikant G. Pharande
Summary: Isocyanide-based multicomponent reactions (IMCR) and ruthenium-catalyzed ring-closing olefin metathesis (RCM) are powerful tools in organic synthesis, and their combination offers an efficient approach for the synthesis of complex cyclic olefins.
Article
Chemistry, Organic
Andrea Ojeda-Porras, Remi Aouzal, Claire Wilson, Joelle Prunet
Summary: Two synthetic routes for the ABC tricycle of Taxol are presented, both involving a relay ring-closing metathesis reaction to form the central B ring. In the first approach, the extender arm is positioned on the A ring, while the C ring bears the relay tether in the second route. Despite the efficient synthesis of metathesis precursors with diverse extender arms, the crucial metathesis reactions failed to yield the target compounds in all cases.