San Vicent del Raspeig, Spain
San Vicent del Raspeig, Spain

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Roiban G.-D.,Babes - Bolyai University | Roiban G.-D.,University of Zaragoza | Serrano E.,University of Zaragoza | Soler T.,Servicios Tecnicos de Investigacion | And 4 more authors.
Organometallics | Year: 2010

Ortho-palladated complexes of (Z)-2-aryl-4-arylidene-5(4H)-oxazolones have been prepared through oxidative addition. The reaction of (Z)-2-phenyl-4-(2- bromobenzylidene)-5(4H)-oxazolone (4) with Pd2(dba)3 · CHCl3 gives the six-membered cyclopalladated dinuclear complex [Pd(μ-Br)(o-C6H4CH=CNC(O)OCPh)]2 (7). The reaction of 7 with PPh3 gives dinuclear 9, which incorporates one phosphine per Pd atom through cleavage of the Pd-N bond, and preserves the bromide bridging system. However, reaction with PPh2Me gives mononuclear 8, which incorporates two phosphines as a results of the cleavage of the μ-Br system and N displacement. In contrast, the reaction of 7 with pyridine gives complex 12 due to simple cleavage of the Br bridge, leaving the N-bonding intact. Therefore, three different reaction pathways have been characterized. The reactivity of the Pd-C bond in 7 has also been examined, and functionalized oxazolones can be obtained. The reaction of 7 with PhI(OAc)2 in acetic acid gives the starting oxazolone C 6H4-2-Br-CH=CNC(O)OCPh (4), through the presumed oxidation of the Pd center and C-Br bond formation by reductive coupling. In contrast, the reaction of the acetate dlmer 14 with PhI(OAc)2 in acetic acid gives C 6H4-2-OAcCH=CNC(O)OCPh (20) through C-O coupling. When treatment of 7 with PhI(OAc)2 is performed in MeOH or EtOH, the oxazolones C6H4-2-OR-CH=CNC(O)OCPh (R = Me (18), Et (19)) are obtained. The reaction of 7 with CO in alcohols ROH gives cleanly the oxazolones C6H4-2-CO2RCH=CNC(O)OCPh (R = Me (21), iPr (22)) through CO migratory insertion into the Pd-C bond and further nucleophilic attack of the RO-fragment. © 2010 American Chemical Society.

Aguilar D.,University of Zaragoza | Fernandez I.,University of Almeria | Cuesta L.,University of Zaragoza | Yanez-Rodriguez V.,University of Almeria | And 4 more authors.
Journal of Organic Chemistry | Year: 2010

Ortho lithiation of N-benzamido-P,P,P-triaryliminophosphoranes through deprotonation with alkyllithium bases was achieved with ortho-C=O and ortho-P=N chemoselectivity. However, the synthetic scope of these processes was rather limited. Ortho-lithiated N-benzamido-P,P,P-triphenyliminophosphorane 8 was efficiently prepared via lithium/halogen exchange of the corresponding ortho-brominated precursor with s-BuLi in THF at -90 °C. The reaction of 8 with a variety of electrophiles provides an easy and mild method for the regioselective synthesis of ortho-modified iminophosphoranes via C- (alkylation and hydroxyalkylation) and C-X (X = I, Si, P, Sn, and Hg) bond-forming reactions. NMR characterization of 8 in THF solution showed that 8 exists as an equilibrium mixture of one monomer and two dimers. The Li atoms of these species become members of five-membered rings through chelation by the ortho-metalated carbon and the carbonyl oxygen. The dimers differ in the relative orientation of the two chelates with respect to the plane defined by the C2Li 2 core. The equilibrium between all species is established by splitting the dimers into monomers and subsequent recombination with formation of a different dimer. © 2010 American Chemical Society.

Aguilar D.,University of Zaragoza | Navarro R.,University of Zaragoza | Soler T.,Servicios Tecnicos de Investigacion | Urriolabeitia E.P.,University of Zaragoza
Dalton Transactions | Year: 2010

The orthopalladation of iminophosphoranes [R3PN-C 10H7-1] (R3 = Ph31, p-Tol 32, PhMe23, Ph2Me 4, N-C10H 7-1 = 1-naphthyl) has been studied. It occurs regioselectively at the aryl ring bonded to the P atom in 1 and 2, giving endo-[Pd(μ-Cl)(C 6H4-(PPh2N-1-C10H 7)-2)-κ-C,N]2 (5) or endo-[Pd(μ-Cl)(C 6H3-(P(p-Tol)2N-C10H 7-1)-2-Me-5)-κ-C,N]2 (6), while in 3 the 1-naphthyl group is metallated instead, giving exo-[Pd(μ-Cl)(C10H 6-(NPPhMe2)-8)-κ-C,N]2 (7). In the case of 4, orthopalladation at room temperature affords the kinetic exo isomer [Pd(μ-Cl)(C10H6-(NPPh2Me)-8)-κ-C,N] 2 (11exo), while a mixture of 11exo and the thermodynamic endo isomer [Pd(μ-Cl)(C6H4-(PPhMeN-C10H 7-1)-2)-κ-C,N]2 (11endo) is obtained in refluxing toluene. The heating in toluene of the acetate bridge dimer [Pd(μ-OAc)(C 10H6-(NPPh2Me)-8)-κ-C,N]2 (13exo) promotes the facile transformation of the exo isomer into the endo isomer [Pd(μ-OAc)(C6H4-(PPhMeN-C10H 7-1)-2)-κ-C,N]2 (13endo), confirming that the exo isomers are formed under kinetic control. Reactions of the orthometallated complexes have led to functionalized molecules. The stoichiometric reactions of the orthometallated complexes [Pd(μ-Cl)(C10H6- (NPPhMe2)-8)-κ-C,N]2 (7), [Pd(μ-Cl)(C 6H4-(PPh2NPh)-2)]2 (17) and [Pd(μ-Cl)(C6H3-(C(O)NPPh3)-2-OMe-4)] 2 (18) with I2 or with CO results in the synthesis of the ortho-halogenated compounds [PhMe2PN-C10H6-I-8] (19), [I-C6H4-(PPh2NPh)-2] (21) and [Ph 3PNC(O)C6H3-I-2-OMe-5] (23) or the heterocycles [C10H6-(NPPhMe2)-1-(C(O))-8]Cl (20), [C 6H5-(NPPh2-C6H4-C(O)-2] ClO4 (22) and [C6H3-(C(O)-1,2-N-PPh 3)-OMe-4]Cl (24). © 2010 The Royal Society of Chemistry.

Aguilar D.,University of Zaragoza | Bielsa R.,University of Zaragoza | Soler T.,Servicios Tecnicos de Investigacion | Urriolabeitia E.P.,University of Zaragoza
Organometallics | Year: 2011

Cycloruthenated complexes [(η6-arene)Ru(C6H 4-2-PPh2=NR)Cl] (arene = benzene, p-cymene; R = Ph, H) containing orthometalated iminophosphoranes have been obtained by transmetalation reactions from Hg(C6H4-2-PPh 2=NR)2 derivatives to [(η6-arene)Ru(μ- Cl)Cl]2. These complexes react cleanly with internal alkynes R 1C=CR2 (R1, R2 = Ph, Et, CO 2Me), KPF6, and CuBr2, yielding the 1,1,2-triphenyl-3,4-di(alkyl/aryl)-2,1λ5-benzazaphosphinin-2- ium heterocycles [C6H4-PPh2-NPh-C(R 1)=C(R2)-3,4]+ as PF6 salts. In all studied cases only the monoinsertion products have been observed. In the case of the asymmetric alkyne MeC=CPh the insertion is regioselective, and the [C 6H4-PPh2-NPh-C(Me)=C(Ph)-3,4]PF6 salt is obtained. © 2011 American Chemical Society.

Nieto S.,University of Zaragoza | Sayago F.J.,University of Zaragoza | Laborda P.,University of Zaragoza | Soler T.,Servicios Tecnicos de Investigacion | And 2 more authors.
Tetrahedron | Year: 2011

The orthopalladation of methyl arylglycinate derivatives has been studied. The reaction proceeds efficiently for different electron-withdrawing and electron-releasing substituents at the aryl ring. The carbonylation of the orthopalladated complexes affords, in a single step, substituted (1H)-isoindolin-1-one-3-carboxylates. These compounds constitute valuable synthetic intermediates and can be transformed diastereoselectively into octahydroisoindole-1-carboxylic acid derivatives, an important scaffold in the synthesis of many biologically active compounds. © 2011 Elsevier Ltd. All rights reserved.

Serrano E.,Centro Universitario Of La Defensa | Soler T.,Servicios Tecnicos de Investigacion | Urriolabeitia E.P.,University of Zaragoza
European Journal of Inorganic Chemistry | Year: 2013

The coordination properties of the ylide-sulfonium salts [Ph 3P=C(H)COCH2S(R1)R2]X [R1 = R2 = Et, X = Br (2); R1 = Me, R2 = Ph, X = ClO4 (5)], the phosphonium-sulfide salt [Ph3PCH 2COCH2SEt]Br (3) and the neutral ylide-sulfide [Ph 3P=C(H)COCH2SPh] (4) towards PdII have been studied. Four different bonding modes have been characterized. The reactions of the ylide-sulfonium salts 2 and 5 with PdCl2(NCMe)2 and NEt3 afford the chelating bis(ylide) complexes cis-[PdCl 2{Ph3PC(H)COC(H)S(R1)R2-κC,C}] [R1 = R2 = Et (6); R1 = Me, R2 = Ph (7)], which are obtained selectively in the meso form (RS/SR). This bonding mode is characterized, including by X-ray crystallography, in the acetylacetonate (acac) complexes [Pd(acac-O,O′){Ph3PC(H)COC(H) S(R1)R2-κC,C}]ClO4 [R1 = R2 = Et (8); R1 = Me, R2 = Ph (9)], which were obtained by reaction of the respective precursor 6 or 7 with AgClO4 and Tl(acac). On the other hand, the C,S-chelating bonding mode has been characterized in [PdCl2{Ph3PC(H)COCH2SR- κC,S}] [R = Et (10); R = Ph (11)], obtained by reaction of the phosphonium-sulfide salt 3 with PdCl2(NCMe)2 and NEt 3 or by reaction of the ylide-sulfide 4 with PdCl2(NCMe) 2, respectively. Furthermore, the tridentate bonding mode μ-S:κC,C,S has been determined in the dinuclear derivative [PdCl{Ph3PC(H)COC(H)SPh-μ-S:κC,C,S}]2 (13), synthesized by reaction of the ylide-sulfide 4 with PdCl2(NCMe) 2 and NEt3. Compound 13 reacts with PPh3 to afford the κC,C-chelate [PdCl{Ph3PC(H)COC(H)SPh-κC,C} PPh3] (14) after cleavage of the sulfide bridge. Compound 14 was obtained as a single diastereoisomer, which was characterized as the D,L form (RR/SS). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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