Article
Chemistry, Organic
Samantha Brooks, Georgina Charlton, Aurelien Letort, Joelle Prunet, Goetz Bucher
Summary: Density-functional and semiempirical calculations on intermediates in ring-closing metathesis reactions in the synthesis of Taxol derivatives show excellent agreement with previous experimental results. The role of steric overloading in determining the outcome is highlighted, with rigidity of the Taxol skeleton playing a key role. Transition states in the final metathesis reaction stage are sensitive to steric effects. Predictions suggest preference for one diastereomer with a compact cyclic carbonate moiety, while a bulkier benzoate-protecting group results in prohibitive activation barriers. The orientation of the pseudoaxial methyl group on the cyclohexene ring likely determines the cascade formation pathway.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
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
Lingbowei Hu, Viresh H. Rawal
Summary: Reported is the total synthesis of (+)-ambiguine G, the first member of the chlorinated pentacyclic ambiguines to be obtained through chemical synthesis. The synthesis involves a convergent strategy starting from (S)-carvone oxide and proceeding in 10 steps, with a key [4+3] cycloaddition and efficient, diastereoselective construction of a key vinylated chloro ketone. An unprecedented one-pot reduction-elimination-oxidation sequence is also featured, transforming an enone to an advanced hydroxylated-diene intermediate.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
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)
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
Sambasivarao Kotha, Deepshikha Singh, Vijayalakshmi Bandi
Summary: An efficient and short synthetic sequence for highly functionalized urazole derivatives has been reported. N-substituted-1,2,4-triazoline-3,5-dione (TAD) was used as a versatile synthetic reagent. Simple reactions including allylation, ring-closing metathesis, and hydrogenation were successfully employed to construct oxygenated urazole derivatives, which may have implications in medicinal chemistry and organic synthesis.
Article
Chemistry, Physical
Valerio Sabatino, Dario Staub, Thomas R. Ward
Summary: The synthesis of N-substituted indoles via ring-closing metathesis of indole precursors with N-terminal alkenes was reported. Good yields (up to 72%) were achieved in aqueous metathesis using commercial catalysts or artificial metalloenzymes. Furthermore, the presence of a second metathesis substrate increased the yield of N-acetylindole.
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)
Article
Polymer Science
Yujin Cha, JiHyeon Hwang, Luis Ramos, Huina Lin, Tianyu Zhu, Chuanbing Tang
Summary: The synthesis of cyclic cobaltocenium and its application in the synthesis of high-performance copolymers have been reported.
Article
Chemistry, Organic
Fatema Jagot, Songeziwe Ntsimango, Kennedy J. Ngwira, Manuel A. Fernandes, Charles B. de Koning
Summary: This article describes the key steps in the synthesis of derivatives of angucycline, tetrangulol, including the catalyzed SuzukiMiyaura cross-coupling reaction, iron-catalyzed ring-closing carbonyl-olefin metathesis reaction, and late-stage oxidation reaction. The chlorinated compounds were obtained as final products.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Nabin Parui, Tirtha Mandal, Jyotirmayee Dash
Summary: An efficient one-step method was used to synthesize various substituted indenones through Grignard addition to indene-1,3-dione, allowing for regiospecific control. This method offers a convenient route to access natural products such as neo-lignans and isoampelopsin D analogues. Additionally, diallyl indenones were synthesized and used as precursors for the facile synthesis of substituted fluorenone derivatives through a ring-closing metathesis (RCM) and aromatization sequence.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Arielle Mann, Matthew D. Hannigan, Bianca L. Dumlao, Chunhua T. Hu, Marcus Weck
Summary: This contribution describes the synthesis of [2.2](1,5)naphthalenoparacyclophane-1,13-diene and examines the effects of differing arene size on its structure and reactivity. The results show that the reactivity of the naphthalenoparacyclophane is diminished due to steric hindrance. However, the incorporation of an electron donor can enable potential applications in optoelectronics, chiral ligands, and planar chiral materials.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
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)
Article
Biochemistry & Molecular Biology
Anna Brodzka, Dominik Koszelewski, Ryszard Ostaszewski
Summary: The goal of diversity-oriented synthesis is to achieve structural diversity of compounds, but issues with low efficiency and multiple purification steps in kinetic resolution exist. A new concept has been proposed to simultaneously form two skeletally and enantiomerically diverse platform molecules in a one-pot protocol to overcome these limitations.
Article
Chemistry, Multidisciplinary
Alejandro Mendez-Ardoy, Alfonso Bayon-Fernandez, Ziyi Yu, Chris Abell, Juan R. Granja, Javier Montenegro
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2020)
Article
Chemistry, Multidisciplinary
Martin Calvelo, Alejandro Lamas, Arcadio Guerra, Manuel Amorin, Rebeca Garcia-Fandino, Juan R. Granja
CHEMISTRY-A EUROPEAN JOURNAL
(2020)
Article
Chemistry, Multidisciplinary
Alberto Fuertes, Manuel Amorin, Juan R. Granja
SUPRAMOLECULAR CHEMISTRY
(2020)
Article
Chemistry, Multidisciplinary
Eva Gonzalez-Freire, Federica Novelli, Antonio Perez-Estevez, Rafael Seoane, Manuel Amorin, Juan R. Granja
Summary: A new class of amphipathic cyclic peptides is described in this study, which assemble in bacteria membranes to form polymeric supramolecular nanotubes giving them strong antimicrobial properties with a broad therapeutic window. The active form is suggested to be the nanotube resulted from the parallel stacking of the cyclic peptide precursors, which is confirmed by several techniques including CD, FTIR, fluorescence, and STEM.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Biophysics
Barbara Claro, Eva Gonzalez-Freire, Martin Calvelo, Lucinda J. Bessa, Erik Goormaghtigh, Manuel Amorin, Juan R. Granja, Rebeca Garcia-Fandino, Margarida Bastos
COLLOIDS AND SURFACES B-BIOINTERFACES
(2020)
Article
Chemistry, Multidisciplinary
Martin Calvelo, Charlotte Lynch, Juan R. Granja, Mark S. P. Sansom, Rebeca Garcia-Fandino
Summary: The study investigated the behavior of two self-assembling peptide motifs through MD simulations, demonstrating the impact of water molecules in nanopores on channel properties. Different water models exhibit varying dynamic behavior in self-assembled cyclic peptide nanotubes, influencing water diffusion and ion flux through the channels.
Article
Chemistry, Multidisciplinary
Federica Novelli, Marcos Vilela, Antia Pazo, Manuel Amorin, Juan R. Granja
Summary: A new method utilizing light-induced [4+4] photocycloaddition was described to form bent tubular structures using cyclic peptide nanotubes. The designed nanotubes are composed of beta- and alpha-amino acids, with the structural changes induced by interdigitated arrangement and homogeneous distribution of anthracene pendants resulting in geometrical modifications in the nanotubes packing.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Alexandre Blanco-Gonzalez, Martin Calvelo, Pablo F. Garrido, Manuel Amorin, Juan R. Granja, Angel Pineiro, Rebeca Garcia-Fandino
Summary: Self-assembling cyclic peptide nanotubes have been studied as synthetic transmembrane channels, with the alternation of natural and nonnatural amino acids allowing control over surface properties and permeability. A computational study was conducted on a new class of peptide motifs, showing potential for drug carrier system design. Molecular dynamics simulations were used to investigate the behavior of water molecules and various ions in nanoconfined environments within these channels.
FRONTIERS IN CHEMISTRY
(2021)
Article
Biochemistry & Molecular Biology
Barbara Claro, Eva Gonzalez-Freire, Juan R. Granja, Rebeca Garcia-Fandino, Jana Gallova, Daniela Uhrikova, Aleksander Fedorov, Ana Coutinho, Margarida Bastos
Summary: Fluorescence spectroscopy is used to study the partition of second-generation D,L-alpha-cyclic peptides in lipid model membranes. The introduction of a hydrocarbon tail significantly improves the partition of the modified peptides to both membrane systems, with the length of the tail being a key factor for the extension of the partition process. Peptides with a tail promote fast membrane leakage compared to the parent peptide, which induces limited leakage.
BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES
(2022)
Article
Biophysics
Barbara Claro, Antonio Peon, Eva Gonzalez-Freire, Erik Goormaghtigh, Manuel Amorin, Juan R. Granja, Rebeca Garcia-Fandino, Margarida Bastos
Summary: Antimicrobial D,L-alpha-cyclic peptides have shown to form complex macromolecular assemblies in the presence of membranes, depending on the negatively charged content of the membrane and lipid/peptide ratio. Experimental techniques and simulations suggest that CPs can self-assemble at the lipid surface into nanotubes or micellar aggregates, revealing possible mechanisms of action involving membrane segregation or disintegration.
COLLOIDS AND SURFACES B-BIOINTERFACES
(2021)
Article
Chemistry, Organic
Juan M. Priegue, Iria Louzao, Ivan Gallego, Javier Montenegro, Juan R. Granja
Summary: Self-assembling cyclic peptide nanotubes can align different molecules on their surface by using cyclic peptides bearing chemoreversible reactive groups. The hydrazide moieties in the cyclic peptides can be released to align other molecules with aldehyde functions on top of the nanotubes. Specific ligands can also be attached to allow supramolecular alignment of corresponding receptors, driven by complementary protein-ligand interactions.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Materials Science, Biomaterials
Alfonso Bayon-Fernandez, Alejandro Mendez-Ardoy, Carmen Alvarez-Lorenzo, Juan R. Granja, Javier Montenegro
Summary: This article introduces the design principles of a new family of self-assembling cyclic octapeptides that can be used as scaffolds for the development of self-healing hydrogels. By inserting different aromatic aldehyde pendants to modulate the hydrophobic/hydrophilic balance and fine-tune the properties of the resulting gel, self-healable hydrogels with viscoelastic properties can be formed.
JOURNAL OF MATERIALS CHEMISTRY B
(2023)
Article
Chemistry, Multidisciplinary
Alberto Fuertes, Manuel Amorin, Juan R. Granja
CHEMICAL COMMUNICATIONS
(2020)
Article
Biochemistry & Molecular Biology
Michele Panciera, Eva Gonzalez-Freire, Martin Calvelo, Manuel Amorin, Juan R. Granja
Article
Chemistry, Physical
Martin Calvelo, Juan R. Granja, Rebeca Garcia-Fandino
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2019)
