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906 results on '"Martin, Ruben"'

157. Dual Catalytic Platform for Enabling sp3 α C−H Arylation and Alkylation of Benzamides

Author

Rand, Alexander W., Yin, Hongfei, Xu, Liang, Giacoboni, Jessica, Martin-Montero, Raul, Romano, Ciro, Montgomery, John, and Martin, Ruben

Abstract

A dual catalytic sp3 α C–H arylation and alkylation of benzamides with organic halides is described. This protocol exhibits an exquisite site selectivity, chemoselectivity, and enantioselectivity pattern, offering a complementary reactivity mode to existing sp3 arylation or alkylations via transition metal catalysis or photoredox events.

Published
2020

158. Ni-Catalyzed Carboxylation of C(sp²)–S Bonds with CO₂: Evidence for the Multifaceted Role of Zn

Author

00372566, Yanagi, Tomoyuki, Somerville, J. Rosie, Nogi, Keisuke, Martin, Ruben, Yorimitsu, Hideki, 00372566, Yanagi, Tomoyuki, Somerville, J. Rosie, Nogi, Keisuke, Martin, Ruben, and Yorimitsu, Hideki

Abstract

Nickel-catalyzed reductive carboxylation reactions of aryl electrophiles typically require the use of metallic reducing agents. At present, the prevailing perception is that these serve as both a source of electrons and as a source of Lewis acids that may aid CO₂ insertion into the Ni–C bond. Herein, we provide evidence for the in situ formation of organometallic species from the metallic reductant, a step that has either been ruled out or has been unexplored in catalytic carboxylation reactions with metal powder reductants. Specifically, we demonstrate that Zn(0) acts as a reductant and that Zn(II) generates arylzinc species that might play a role in the C(sp²)–S carboxylation of arylsulfonium salts. Overall, the reductive Ni-catalyzed C(sp²)–S carboxylation reaction proceeds under mild conditions in a non-amide solvent, displays a wide substrate scope, and can be applied to the formal para C–H carboxylation of arenes.

Published
2020

159. Secreted Phospholipase A2-IIA Modulates Transdifferentiation of Cardiac Fibroblast through EGFR Transactivation: An Inflammation–Fibrosis Link

Author

Martin, Ruben, Gutierrez, Beatriz, Cordova, Claudia, San Roman, Alberto, Alvarez, Yolanda, Hernandez, Marita, Cachofeiro Ramos, Victoria, Nieto, Maria L, Martin, Ruben, Gutierrez, Beatriz, Cordova, Claudia, San Roman, Alberto, Alvarez, Yolanda, Hernandez, Marita, Cachofeiro Ramos, Victoria, and Nieto, Maria L

Abstract

Secreted phospholipase A2-IIA (sPLA2-IIA) is a pro-inflammatory protein associated with cardiovascular disorders, whose functions and underlying mechanisms in cardiac remodelling are still under investigation. We herein study the role of sPLA2-IIA in cardiac fibroblast (CFs)-to-myofibroblast differentiation and fibrosis, two major features involved in cardiac remodelling, and also explore potential mechanisms involved. In a mice model of dilated cardiomyopathy (DCM) after autoimmune myocarditis, serum and cardiac sPLA2-IIA protein expression were found to be increased, together with elevated cardiac levels of the cross-linking enzyme lysyl oxidase (LOX) and reactive oxygen species (ROS) accumulation. Exogenous sPLA2-IIA treatment induced proliferation and differentiation of adult rat CFs. Molecular studies demonstrated that sPLA2-IIA promoted Src phosphorylation, shedding of the membrane-anchored heparin-binding EGF-like growth factor (HB-EGF) ectodomain and EGFR phosphorylation, which triggered phosphorylation of ERK, P70S6K and rS6. This was also accompanied by an up-regulated expression of the bone morphogenic protein (BMP)-1, LOX and collagen I. ROS accumulation were also found to be increased in sPLA2-IIA-treated CFs. The presence of inhibitors of the Src/ADAMs-dependent HB-EGF shedding/EGFR pathway abolished the CF phenotype induced by sPLA2-IIA. In conclusion, sPLA2-IIA may promote myofibroblast differentiation through its ability to modulate EGFR transactivation and signalling as key mechanisms that underlie its biological and pro-fibrotic effects., Ministerio de Economía y Competitividad (MINECO)/FEDER, Instituto de Salud Carlos III (ISCIII), Depto. de Fisiología, Fac. de Medicina, TRUE, pub

Published
2020

160. Dual Catalytic Strategy for Forging sp(2)-sp(3) and sp(3)-sp(3) Architectures via beta-Scission of Aliphatic Alcohol Derivatives

Author

Universitat Rovira i Virgili, Cong, Fei; Lv, Xin-Yang; Day, Craig S.; Martin, Ruben, Universitat Rovira i Virgili, and Cong, Fei; Lv, Xin-Yang; Day, Craig S.; Martin, Ruben

Abstract

A dual platform for forging sp(2)-sp(3) and sp(3)-sp(3) carbon bonds via catalytic beta-scission of aliphatic alcohol derivatives with both aryl and alkyl halides is disclosed. This protocol is distinguished by its wide substrate scope and broad applicability, even in the context of late-stage functionalization.

Published
2020

162. Pd-Catalyzed Arylation of 1,2-Amino Alcohol Derivatives via β-Carbon Elimination.

Author

Sau, Miriam, Pericàs, Miquel A., and Martin, Ruben

Subjects
ARYLATION, ARYL halides, ALCOHOL, AMINO alcohols, ENAMINES
Abstract

Herein, we describe a Pd-catalyzed arylation of 1,2-amino alcohols with aryl halides enabled by a retroallylation manifold. This protocol constitutes a new entry point to β-arylated aldehydes via the intermediacy of in situ generated enamine intermediates. The protocol is characterized by its exquisite regioselectivity profile and broad substrate scope – including challenging substrate combinations – even in an enantioselective manner. [ABSTRACT FROM AUTHOR]

Published
2022
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163. Conformational Flexibility as a Tool for Enabling Site-Selective Functionalization of Unactivated sp3C–O Bonds in Cyclic Acetals

Author

Romano, Ciro, Talavera, Laura, Gómez-Bengoa, Enrique, and Martin, Ruben

Abstract

A dual catalytic manifold that enables site-selective functionalization of unactivated sp3C–O bonds in cyclic acetals with aryl and alkyl halides is reported. The reaction is triggered by an appropriate σ*–p orbital overlap prior to sp3C–O cleavage, thus highlighting the importance of conformational flexibility in both reactivity and site selectivity. The protocol is characterized by its excellent chemoselectivity profile, thus offering new vistas for activating strong σ sp3C–O linkages.

Published
2022
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175. sp3Bis‐Organometallic Reagents via Catalytic 1,1‐Difunctionalization of Unactivated Olefins.

Author

Sun, Shang‐Zheng, Talavera, Laura, Spieß, Philipp, Day, Craig S., and Martin, Ruben

Subjects
ALKENES, CATALYSIS
Abstract

A catalytic 1,1‐difunctionalization of unactivated olefins en route to sp3bis‐organometallic B,B(Si)‐reagents is described. The protocol is characterized by exceptional reaction rates, mild conditions, wide scope, and exquisite selectivity pattern, constituting a new platform to access sp3bis‐organometallics. [ABSTRACT FROM AUTHOR]

Published
2021
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177. Catalytic Intermolecular Dicarbofunctionalization of Styrenes with CO2 and Radical Precursors

Author

Yatham, Veera Reddy, Shen, Yangyang, and Martin, Ruben

Abstract

A redox-neutral intermolecular dicarbofunctionalization of styrenes with CO2 at atmospheric pressure and carbon-centered radicals is described. This mild protocol results in multiple C–C bond-forming reactions from simple precursors in the absence of stoichiometric reductants, thus exploiting a previously unrecognized opportunity that complements existing catalytic carboxylation events.

Published
2017

178. Switchable Site-Selective Catalytic Carboxylation of Allylic Alcohols with CO2

Author

van Gemmeren, Manuel, Börjesson, Marino, Tortajada, Andreu, Sun, Shang-Zheng, Okura, Keisho, and Martin, Ruben

Subjects
food and beverages
Abstract

A switchable site-selective catalytic carboxylation of allylic alcohols has been developed in which CO2 is used with dual roles, both facilitating C–OH cleavage and as C1 source. This protocol is characterized by its mild conditions, absence of stoichiometric organometallic reagents, broad scope and exquisite regiodivergency that can be modulated by the ligand employed.

Published
2017

187. Tackling Remote sp3 C−H Functionalization via Ni‐Catalyzed "chain‐walking" Reactions.

Author

Janssen‐Müller, Daniel, Sahoo, Basudev, Sun, Shang‐Zheng, and Martin, Ruben

Subjects
NICKEL catalysts, COLLEGE laboratories, ORGANOMETALLIC chemistry, ISOMERIZATION, CARBON-hydrogen bonds
Abstract

Nickel catalysts have recently played an important role for rapidly and reliably converting feedstock chemicals into valuable compounds of interest for both pharmaceutical and academic laboratories. Herein, we summarize the recent advances on the ability of nickel catalysts to trigger olefin isomerization via "chain‐walking", causing a displacement of the nickel catalyst throughout the alkyl chain while opening up new grounds for forging C−C and C‐heteroatom linkages at remote, yet unfunctionalized, sp3 C−H bonds. [ABSTRACT FROM AUTHOR]

Published
2020
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199. México se cimbra a mitad del sexenio

Author

Núñez Bustillos, Juan Carlos, Núñez de la Peña, Francisco Javier, Negrete Cárdenas, Sergio, Román Morales, Luis Ignacio, Rocha Quintero, Jorge Enrique, Valdivia García, Jorge, Martín Martín, Rubén, Cárdenas López, Alejandro, Bautista Farías, José, Salazar Ruiz, Ricardo Manuel, Urrutia de la Torre, Francisco, Navarro Ramos, Jesús Arturo, Cruz Martinez, Mario, Núñez Bustillos, Juan Carlos, Núñez de la Peña, Francisco Javier, Negrete Cárdenas, Sergio, Román Morales, Luis Ignacio, Rocha Quintero, Jorge Enrique, Valdivia García, Jorge, Martín Martín, Rubén, Cárdenas López, Alejandro, Bautista Farías, José, Salazar Ruiz, Ricardo Manuel, Urrutia de la Torre, Francisco, Navarro Ramos, Jesús Arturo, and Cruz Martinez, Mario

Abstract

En el segundo semestre de 2015 se cumplió el tercer año de la administración del presidente Enrique Peña Nieto, sobre el cual estuvieron los reflectores, pero no por su informe de gobierno sino porque el periodo se caracterizó por una serie de acontecimientos que cimbraron al país, tanto en el escenario económico como en el político y el social, varios de los cuales afectaron negativamente la imagen presidencial. En el ámbito político, el golpe lo dio Joaquín “Chapo” Guzmán, quien con su espectacular fuga de una prisión de “alta seguridad” dejó muy mal parado al presidente y a su secretario de Gobernación, que habían prometido que el narcotraficante no volvería a escapar. En tanto que en el ámbito económico, la incontenible debacle del peso y la caída del precio del crudo de exportación terminaron por afectar las finanzas públicas y la promesa presidencial de crecimiento y prosperidad. En la parte social, la Suprema Corte de Justicia de la Nación dio la nota al obligar al debate de dos temas “tabú” en México: el matrimonio entre personas del mismo sexo y el consumo lúdico de marihuana. El aval de la SCJN generó tanto aplausos como críticas y marcó el cierre de un semestre que, por los avances y por los retrocesos experimentados, dejó huella en el país.

Published
2016

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