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.
Article
Chemistry, Multidisciplinary
Nasrin Jahan, Arijit Das, Inul Ansary
Summary: In this study, a simple method for cross-aldol condensation reaction was developed to synthesize two types of compounds, and a series of dibenzo-fused macrocycles were obtained through ring-closing metathesis reaction. The cis/trans configurations of the products were confirmed by H-1-NMR spectral data.
Article
Chemistry, Multidisciplinary
Ammundi Jayavel Chirranjeevi Padmashrija, Sathananthan Kannadasan, Ponnusamy Shanmugam
Summary: A convenient and efficient synthesis of 3-spiro cycloalkene fused 7-aza-2-indalones has been achieved via ring-closing metathesis (RCM) using Grubbs-II catalyst from 3,3'-di- or N,3,3'-tri-allyl/homoallyl/pentenyl 7-aza-2-indalones. The reaction scope was demonstrated by synthesizing spiro products of various ring sizes (n=5, 7, and 18) with different alkenylation agents as substrates. In addition to typical RCM products, a cross metathesis (CM) product and a macrocyclic, 18-membered bis-spirodiene were also observed.
Article
Chemistry, Organic
Kevin George, Sathananthan Kannadasan
Summary: A sequential synthetic process was developed for the synthesis of quinoline/oxindole appended phenylvinyl-2,5-dihydrofuran derivatives. The process involved multiple steps, starting with nucleophilic addition and O-allylation, followed by ring-closing enyne metathesis. The structures and stereochemistry of the synthesized compounds were confirmed by spectroscopic analysis and XRD studies.
Article
Chemistry, Multidisciplinary
Steven T. Diver, Elise Glickert, Laurence N. Rohde, Therese Wild
Summary: In this study, a variety of 1-aryl-1,3-dienes were converted from E to Z isomers through photocatalysis using Ru(bpy)(3)[PF6](2) and blue LED light. The enrichment of Z-isomers was achieved by selective triplet energy transfer from the photocatalyst. By combining catalytic ene-yne metathesis (EYM) and photocatalysis, a stereoconvergent synthesis of Z-1,3-dienes was achieved.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Organic
Tanya Pieterse, Charlene Marais, Barend C. B. Bezuidenhoudt
Summary: Isoflav-3-enes with natural substitution patterns were synthesized through a one-pot Wittig methylenation - etherification - Wittig methylenation reaction, followed by ring-closing metathesis catalyzed by the Grubbs second generation catalyst. This method achieved the synthesis of a series of novel 1-[(2-phenylallyl)oxy]-2-vinylbenzenes in good yields (61 - 89%). Olefin metathesis thus provides a common strategy for the synthesis of all three flavonoid subclasses, i.e. the flavonoids, neoflavonoids and isoflavonoids.
Article
Chemistry, Organic
Tanya Pieterse, Charlene Marais, Barend C. B. Bezuidenhoudt
Summary: The Tebbe methylenation and Grubbs second generation catalyst ring-closing metathesis were investigated as crucial steps in the synthesis of flav-2-enes with natural substitution patterns. The study discusses the influence of aromatic substituents on the electron densities of allyl and vinyl moieties and their effects on methylenation and ring-closing metathesis.
Article
Chemistry, Physical
Kevin Basemann, Bradley M. Schmidt, Aaron D. Sadow
Summary: The study of reaction conditions for ruthenium-catalyzed ene-yne metathesis has shown that substituents and functional groups on the terminal alkyne reactant play a significant role in affecting the outcomes. Utilizing different methods and optimized conditions can lead to high turnovers and yields. Various research approaches and reaction conditions can improve the efficiency and conversion rates of the reactions.
Article
Chemistry, Multidisciplinary
Andrii Myshko, Galyna Mrug, Kostyantyn Kondratyuk, Bohdan Demydchuk, Svitlana Bondarenko, Mykhaylo Frasinyuk
Summary: Efficient methods for synthesizing pyrazole-based aurones were developed. The reactions of benzofuran-3(2H)-ones with 1H-pyrazole-3(5)/4-carboxaldehydes or 4-[(dimethylamino)methylene]-2,4-dihydro-3H-pyrazol-3-ones produced 2-pyrazolylmethylene-1-benzofuran-3(2H)-ones or 2-[(3(5)-hydroxy-1H-pyrazol-4-yl)methylene]-1-benzofuran-3(2H)-ones, respectively. The reaction of 2-[(dimethylamino)methylene]-1-benzofuran-3(2H)-ones with 1-methyl-5-aminopyrazoles yielded 2-[(5-amino-1-methyl-1H-pyrazol-4-yl)methylene]-1-benzofuran-3(2H)-ones and 1-methyl-1H-[1]benzofuro[3,2-b]pyrazolo[4,3-e]pyridines as minor products.
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.
Article
Chemistry, Organic
Frank Schmidt, Aparna Viswanathan Ammanath, Friedrich Goetz, Martin E. Maier
Summary: A new synthesis route was established for the macrolactone antibiotic berkeleylactone A. The synthesis involved ring-closing alkyne metathesis (RCAM) of an ester substrate with 1-propynyl termini. The carboxylic part of the substrate was assembled using alkyne chemistry, while the alcohol part of the ester was synthesized through propylene oxide opening and triple bond migration reactions. After successful RCAM, the triple bond was selectively hydrogenated and the 4,5-diol was oxidized to obtain the desired derivative. The thioether formation and reduction of the 8,9-double bond were also achieved. However, the antimicrobial activity of the analog was found to be slightly reduced.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Myron Triantafyllakis, Sam Alexander, Sophie Woolford, Claire Wilson, J. Stephen Clark
Summary: The fully functionalized A-F fragment of the Pacific ciguatoxin CTX3C has been synthesized using specific reaction sequences and synthesis routes, achieving the construction of a multi-ring system and the introduction of functional groups.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Review
Chemistry, Multidisciplinary
Tahira Bano, Ameer Fawad Zahoor, Nasir Rasool, Muhammad Irfan, Asim Mansha
Summary: Ruthenium catalysis can synthesize various natural and biologically active compounds, and ruthenium-based catalysts are well-known for their broad applications and high efficiency.
JOURNAL OF THE IRANIAN CHEMICAL SOCIETY
(2022)
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.
