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Buarque C.D.,Pontifical Catholic University of Rio de Janeiro | Alonso D.A.,Institute Sintesis Organica ISO | Najera C.,Institute Sintesis Organica ISO
European Journal of Organic Chemistry | Year: 2011

The oxyarylation of dihydronaphthalene (1a), two electron-rich (1b,c) and one electron-poor (2) chromenes with different o-iodophenols and their acetates 3a-h has been investigated by using either Pd(OAc)2 (10 mol-%) as precatalyst and Ag2CO3 as base in acetone as solvent or oxime pallada-cycle 5 as precatalyst and dicyclohexylamine as base in DMA/H 2O. The reactions, which were strongly accelerated under microwave heating, afforded the best yields when electron-rich chromenes reacted with o-iodophenols substituted by electron-withdrawing groups in the presence Pd(OAc)2 and Ag2CO3. However, in the case of electron-poor chromenes the best yield was obtained with the electron-rich o-iodophenol 3g. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nador F.,CONICET | Moglie Y.,CONICET | Vitale C.,CONICET | Yus M.,Institute Sintesis Organica ISO | And 2 more authors.
Tetrahedron | Year: 2010

A new methodology for the partial reduction of polycyclic aromatic and heteroaromatic hydrocarbons under mild reaction conditions is presented, the process being a reasonable alternative to the catalytic hydrogenation or the Birch reaction. The reduction protocol described is based on the use of cobalt or manganese nanoparticles generated in situ in a simple and economic way, by reduction of commercially available CoCl2·6H2O or MnCl2·2H2O in the presence of lithium sand and the corresponding PAH, acting itself as an electron carrier. The use of a deuterium-oxide-containing cobalt(II) salt allows the simple preparation of deuterium labeled products. The regiochemistry and degree of reduction in the case of 1-substituted naphthalene derivatives markedly depends on the nature of the metal-NPs used. © 2010 Elsevier Ltd. All rights reserved.

Penafiel I.,Institute Sintesis Organica ISO | Pastor I.M.,Institute Sintesis Organica ISO | Yus M.,Institute Sintesis Organica ISO
Tetrahedron | Year: 2010

The reaction of (chloromethyl)cyclopropane 5 and (bromomethyl)cyclobutane 8 with lithium and a substoichiometric amount of DTBB, in the presence of different carbonyl compounds as electrophiles, in THF at -78 °C leads, after hydrolysis, to the corresponding cycloalkyl alcohols 6 and 9, respectively. However, when the same starting materials are lithiated using naphthalene as catalyst in diethyl ether and at higher temperature (0 or 25 °C), and then react with the same electrophiles, the final hydrolysis yields the corresponding unsaturated alcohols 7 and 10, respectively. © 2010 Elsevier Ltd. All rights reserved.

Martinez-Asencio A.,Institute Sintesis Organica ISO | Ramon D.J.,Institute Sintesis Organica ISO | Yus M.,Institute Sintesis Organica ISO
Tetrahedron Letters | Year: 2010

Copper(II) acetate is a versatile, cheap, and simple catalyst for the selective N-monoalkylation of amino derivatives with poor nucleophilic character, such as aromatic and heteroaromatic amines as well as sulfonamides, using in all cases primary alcohols as initial source of the electrophiles, through a hydrogen autotransfer process. In the case of sulfonamides, the monoalkylation process followed by a naphthalene-catalyzed reductive deprotection gives primary amines, which is an indirect alternative to the direct monoalkylation of ammonia. © 2009 Elsevier Ltd. All rights reserved.

Alonso F.,Institute Sintesis Organica ISO | Riente P.,Institute Sintesis Organica ISO | Sirvent J.A.,Institute Sintesis Organica ISO | Yus M.,Institute Sintesis Organica ISO
Applied Catalysis A: General | Year: 2010

Nickel nanoparticles, readily prepared by reduction of nickel(II) chloride with lithium and a catalytic amount of DTBB, have been used in the transfer hydrogenation of carbonyl compounds and have been fully characterised by different means. The reaction rate of the transfer hydrogenation was found to be dependent on the acetophenone and isopropanol concentration but independent on the amount of lithium chloride. The deactivation of the catalyst after reuse has been mainly attributed to surface oxidation but not to coke formation. All the experiments performed are in agreement with the process being of heterogeneous nature. The nickel nanoparticles unveiled a superior behaviour in comparison with commercially available nickel catalysts. © 2010 Elsevier B.V. All rights reserved.

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