
Victorio CadiernoUniversity of Oviedo | UNIOVI · Department of Organic and Inorganic Chemistry
Victorio Cadierno
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January 2010 - present
Publications
Publications (232)
N-Heterocyclic carbenes (NHCs) are nowadays one of the most widely employed ligands in organometallic chemistry and homogeneous catalysis due to the inherent stability of the metal-carbene bond and the ease of modification of the backbone as well as the N-wingtips substituents of these ligands. The functionalization of NHCs with hydrophilic groups...
A new synthetic procedure for obtaining two previously reported donor-acceptor butadiene dyes, namely 5-(3,3-bis(4-methoxyphenyl)allylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione and 5-(3,3-bis(4-(dimethylamino)phenyl)allylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione, based on the InCl3-catalyzed coupling 1,3-dieth...
Although the application of arene-osmium(II) complexes in homogeneous catalysis has been much less studied than that of their ruthenium analogues, different works have shown that, in some instances, a comparable or even superior effectiveness can be achieved with this particular class of compounds. This review article focuses on the catalytic appli...
The hydration of nitriles is an important transformation because the resulting primary amides present a huge number of applications in synthetic organic chemistry, as well as industrial and pharmaceutical interest. Metallic compounds (complexes, oxides, and nanoparticles) are known to catalyze the hydration of nitriles by activating the nitrile sub...
The title compound, i.e., [RuCl2(η6-p-cymene)(PPh2NHnPr)] (2), was obtained in a 71% yield by reacting a toluene solution of the chlorophosphine complex [RuCl2(η6-p-cymene)(PPh2Cl)] (1) with two equivalents of n-propylamine at room temperature. The aminophosphine complex 2 was characterized by elemental analysis, multinuclear NMR (31P{1H}, 1H and 1...
The use of organometallic compounds in organic chemistry is one of the cornerstones of the modern synthetic methodology for the activation and generation of new bonds in a molecule [...]
The title compound was synthesized by electrophilic cyanation of commercially available (R)-4-chloro-α-methylbenzylamine with cyanogen bromide in diethyl ether, and isolated as a yellow oil in 84% yield. It was characterized by 1H and 13C{1H] NMR, IR, HRMS, and specific rotation measurements.
The catalytic hydration of nitriles and the rearrangement of aldoximes are atom-economical routes to generate primary amides of great academic and industrial interest. Among the different families of catalysts that have been developed for these transformations, the most extensively studied is that of (η⁶-arene)-ruthenium(II) derivatives since, by a...
The synthesis of two novel enol esters, namely hex-1-en-2-yl indole-2-carboxylate and hex-1-en-2-yl 1-(hex-1-en-2-yl)-indole-2-carboxylate, is presented. Both compounds were generated by addition of indole-2-carboxylic acid to 1-hexyne employing [RuCl2(η6-p-cymene)(PPh3)] and [AuCl(PPh3)]/AgPF6, respectively, as catalysts.
The synthesis of a large variety of ureas R1R2NC(=O)NH2 (R1 and R2 = alkyl, aryl or H; 26 examples) was successfully accomplished by hydration of the corresponding cyanamides R1R2NC≡N using the phosphinous acid-based complexes [MCl2(η6-p-cymene)(PMe2OH)] (M = Ru (1), Os (2)) as catalysts. The reactions proceeded cleanly under mild conditions (40-70...
In the last years there has been an increasing interest in the search for protocols to obtain β-haloenol esters in an efficient and selective manner as they are versatile building blocks in synthetic organic chemistry. In this article, metal-catalyzed transformations allowing the access to both acyclic and cyclic (i.e., haloenol lactones) β-haloeno...
The synthesis of a series of arene-osmium(II) complexes containing phosphinite-type ligands, namely, [OsCl2(η6-p-cymene){R2PO(CH2)nPh}] (R = Ph, n = 1 (4a), 2 (4b), 3 (4c); R = iPr, n = 1 (5a), 2 (5b), 3 (5c)) and [OsCl2(η6-benzene){iPr2PO(CH2)2Ph}] (7), is presented. All these compounds were characterized by elemental analysis and multinuclear NMR...
The preparation of the tethered arene-ruthenium(II) complexes [RuCl2{η6:κ1(P)-C6H5(CH2)nOPR2}] (R = Ph, n = 1 (9a), 2 (9b), 3 (9c); R = iPr, n = 1 (10a), 2 (10b), 3 (10c)) from the corresponding phosphinite ligands R2PO(CH2)nPh (R = Ph, n = 1 (1a), 2 (1b), 3 (1c); R = iPr, n = 1 (2a), 2 (2b), 3 (2c)) is presented. Thus, in a first step, the treatme...
The synthesis and characterization of novel gold(I) complexes containing hydrophilic ferrocenylphosphino sulfonate ligands, i.e., compounds [AuCl{(η5-C5H3PR2(SO3iPr))Fe(η5-C5H5)}] (R = Ph (2a), p-Tol (2b), Cy (2c)), are presented, including a single-crystal X-ray diffraction study on 2a. Complexes 2a–c were checked as catalysts for the intermolecul...
In this Perspective article, recent advances in the chemistry of platinum group metal complexes containing mono- and dianionic guanidinate ligands, i.e. [(RN)2C-NR2]- and [(RN)2C=NR]2-, respectively, are presented. Synthetic and structural...
A cascade process for the straightforward one-pot conversion of β-ketonitriles into β-hydroxyamides is presented. The process, that proceeds in water employing the arene-ruthenium(II) complex [RuCl2(η⁶-p-cymene){P(4-C6H4F)2Cl}] as catalyst in combination with sodium formate, involves the initial hydration of the β-ketonitrile substrates to generate...
A straightforward and broad-scope procedure to obtain symmetrically substituted buta-1,3-diene-1,4-diyl diesters, based on the homocoupling of the corresponding (Z)-β-iodoenol esters, is presented. It involves the use of a catalytic system composed of [NiCl2(PPh3)2] (10 mol%), NaI (10 mol%), and excess of Zn dust. The reactions proceed in THF at ro...
The synthesis and double asymmetric hydrogenation of (Z,Z)-1,3-diene-1,4-diyl diacetates is described. In this reaction C2/meso ratios up to 80:20 and enantioselectivities up to 97 % ee have been achieved. As...
A dual ruthenium/ketoreductase catalytic system has been developed for the conversion of β‐ketonitriles into optically active β‐hydroxyamides through an unprecedented hydration/bioreduction cascade process in aqueous medium working in concurrent mode. The ketoreductase‐mediated ketone reduction took place with exquisite stereoselectivity and it was...
A series of half-sandwich ruthenium(II) complexes containing η⁶-coordinated 2-phenylethanol and 3-phenylpropanol ligands, namely [RuCl2{η⁶-C6H5CH2(CH2)nCH2OH}(PR3)] (PR3 = PMe3, PPh3, P(OMe)3, P(OEt)3, P(OⁱPr)3, P(OPh)3; n = 0 (1a–f), 1 (2a–f)), have been investigated as catalysts for the tandem isomerization/Claisen rearrangement of diallyl ethers...
Three different series of half‐sandwich Os(II) complexes, namely [OsCl2(η⁶‐p‐cymene){PPh2(NR2)}] [R=Me (5a), Et (5b)], [OsCl2(η⁶‐p‐cymene){PPh(NR2)2}] [R=Me (6a), Et (6b)] and [OsCl2(η⁶‐p‐cymene){P(NR2)3}] [R=Me (7a), Et (7b)], have been synthesized. These species proved to be catalytically active for the selective hydration of organonitriles, with...
The platinum(II) complex [PtCl2(COD)] (2; COD = 1,5‐cyclooctadiene) reacted with 1 and 2 equivalents of 2‐(diphenylphosphino)benzaldehyde oxime (1) to generate [PtCl2{2‐(P,N)‐2‐Ph2PC6H4CH=NOH}] (3) and [Pt{2‐(P,N)‐2‐Ph2PC6H4CH=NOH}2][Cl]2 (4), respectively. Deprotonation of the oxime hydroxyl group of 3 with Na2CO3 led to the selective formation...
The metal-catalyzed addition of carboxylic acids to alkynes is a very effective tool for the synthesis of carboxylate-functionalized olefinic compounds in an atom-economical manner. Thus, a large variety of synthetically useful lactones and enol-esters can be accessed through the intra- or intermolecular versions of this process. In order to reduce...
The synthesis and characterization of three novel ferrocenylphosphino sulfonates, namely [(η⁵-C5H3PR2(SO3i-Pr))Fe(η⁵-C5H5)] (R = Ph, p-Tol, Cy), is presented along with their solid-state X-ray crystal structures. Preliminary studies on the utility of these compounds as auxiliary ligands in aqueous catalysis, in particular for the ruthenium-catalyze...
The combination of the metal-catalyzed cycloisomerization of alkynes containing a tethered nucleophile as substituent in aqueous media (followed by the spontaneous hydrolysis, hydroalkoxylation or aminolysis of the transiently formed 5-membered heterocycles), with the subsequent enantioselective ketone bioreduction (mediated by KREDs) has been achi...
The intermolecular addition of carboxylic acids to alkynes is one of the most straightforward and atom-economical methods currently available for the preparation of synthetically useful enol esters. However, the vast majority of works have focused on the use of terminal alkynes, substrates much more reactive than their corresponding internal counte...
The preparation of the first mononuclear Ru(II), Ru(IV) and Os(II) complexes containing the anion of the bicyclic guanidine 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (Hhpp) as a chelating ligand, namely [RuX{2-(N,N´)-hpp}(6-arene)] [arene = p-cymene, X = Cl (2a), Br (2b), I (2c); arene = C6Me6, X = Cl (7)], [RuCl{2-(N,N´)-hpp}(3:3-C10...
In the presence of catalytic amounts of the Au(I) cation [Au(PPh3)](+), a large variety of (Z)-beta-iodoenol esters (39 examples) could be synthesized under mild reaction conditions through the regio-and stereospecific intermolecular addition of carboxylic acids to iodoalkynes. Sonogashira coupling of representative (Z)-beta-iodoenol esters with te...
We report herein the efficient hydro-oxycarbonylation of symmetrical and unsymmetrical internal alkynes with carboxylic acids in water at 60 °C, employing the catalytic system [AuCl(PPh3)]/AgOAc (5 mol%). This simple and eco-friendly protocol allows for the synthesis of a wide variety of trisubstituted enol esters (37 examples) in high yields and w...
In the presence of catalytic amounts of the Au(I) cation [Au(PPh3)]+, a large variety of (Z)-β-iodoenol esters (39 examples) could be synthetized under mild reaction conditions through the regio- and stereospecific intermolecular addition of carboxylic acids to iodoalkynes. Sonogashira coupling of representative (Z)-β-iodoenol esters with terminal...
An unprecedented hydration/transfer hydrogenation tandem process for the catalytic conversion of β-ketonitriles into synthetically useful β-hydroxyamides in water has been developed, making use of the ruthenium(II) complex [RuCl2(η⁶-p-cymene){P(4-C6H4F)2Cl}] in combination with sodium formate.
Several mononuclear ruthenium(iv) complexes with phosphinous acid ligands [RuCl2(η(3):η(3)-C10H16)(PR2OH)] have been synthesized (78-86% yield) by treatment of the dimeric precursor [{RuCl(μ-Cl)(η(3):η(3)-C10H16)}2] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) with 2 equivalents of different aromatic, heteroaromatic and aliphatic secondary phosph...
The catalytic hydration of nitriles into amides, in water under neutral conditions, has been studied using a series of arene-ruthenium(II) complexes containing commercially available chlorophosphines as auxiliary ligands, i.e. compounds [RuCl2(η6-p-cymene)(PR2Cl)] (R = aryl, heteroaryl or alkyl group). In the reaction medium, the coordinated chloro...
Efficient catalytic processes employing the bis(allyl)-ruthenium(IV) complexes [{RuCl(mu-Cl)(eta(3):eta(3)-C10H16)}(2)] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl), [RuCl2(eta(3):eta(2):eta(3)-C12H18)] (C12H18 = dodeca-2,6,10-triene-1,12-diyl) and [RuCl2(eta(3):eta(3)-C10H16](L)] (L = neutral 2e(-) donor ligand) have been developed in our group...
Broad scope synthesis of (Z)-1-alkyl-2-arylvinyl acetates 3 is reported by using two complementary methods. The first one uses a sequence composed by a stereospecific gold-catalyzed addition of acetic acid to 1-iodo-alkynes, followed by a Suzuki coupling. By the second, 1-methyl-2-arylvinyl substrates have been obtained selectively as the Z isomers...
In this work, the preparation of the first ruthenium complexes containing a phosphino-oxime ligand is presented. Thus, the reaction of cis-[RuCl2(DMSO)4] (3) with 2.4 equivalents of 2-Ph2PC6H4CHNOH (1) in refluxing THF led to the clean formation of the octahedral ruthenium(II) derivative cis,cis,trans-[RuCl2{κ2-(P,N)-2-Ph2PC6H4CHNOH}2] (5), whose s...
The novel guanidinate-osmium(II) complexes [OsCl(2-(N,N')-C(NR)(NiPr)NHiPr)(6-p-cymene)] [R = Ph (3a), 4-C6H4F (3b), 4-C6H4Cl (3c), 4-C6H4CF3 (3d), 3-C6H4CF3 (3e), 3,5-C6H3(CF3)2 (3f), 4-C6H4CN (3g), 4-C6H4Me (3h), 3-C6H4Me (3i), 2-C6H4Me (3j), 4-C6H4tBu (3k), 2,6-C6H3iPr2 (3l), 2,4,6-C6H2Me3 (3m)] have been synthesized in high yields (70-88%) by t...
Novel donor-acceptor butadiene chromophores were synthesized by Knoevenagel condensation of different diaryl-substituted enals with 3-(dicyanomethylidene)indan-1-one and 1,3-bis(dicyanomethylidene)indane. The structures of two of these compounds were unambiguously confirmed by means of single-crystal X-ray diffraction. The absorption spectra of the...
The catalytic hydration of benzonitrile and acetonitrile has been studied by employing different arene-ruthenium(II) complexes with phosphinous (PR2 OH) and phosphorous acid (P(OR)2 OH) ligands as catalysts. Marked differences in activity were found, depending on the nature of both the P-donor and η(6) -coordinated arene ligand. Faster transformati...
The rearrangement of aldoximes to primary amides has been studied using the commercially available bis(allyl)-ruthenium(IV) complex [{RuCl(μ-Cl)(η3:η3-C10H16)}2] (1; C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) as a catalyst under thermal and microwave heating. The reactions proceeded cleanly in a mixture of water/glycerol (1:1) at 120-150°C, with...
The coordination of the phosphino-alcohol ligands 2-Ph2PC6H4CH(R)OH (R = H, Me) onto an arene-ruthenium(II) fragment gave rise to the formation of complexes of general formula [RuCl2{2-Ph2PC6H4CH(R)OH}(η6-arene)] (R = H, arene = C6H6 (3a), p-cymene (3b), mesitylene (3c), C6Me6 (3d); R = Me, arene = p-cymene (5b)). In solution, different isomers wer...
Treatment of [PdCl2(COD)] (COD = 1,5-cyclooctadiene) with 1 and 2 equivalents of 2-(diphenylphosphino)benzaldehyde oxime, in dichloromethane at room temperature, led to the selective formation of [PdCl2{κ2-(P,N)-2-Ph2PC6H4CH=NOH}] (1) and [Pd{κ2-(P,N)-2-Ph2PC6H4CH=NOH}2][Cl]2 (2), respectively, which represent the first examples of Pd(II) complexes...
The novel bis(allyl)ruthenium(IV) guanidinate complexes [RuCl{κ2(N,N′)-C(NR)(NiPr)-NHiPr}(η3:η3-C10H16)] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl; R = Ph (3a), 4-C6H4F (3b), 4-C6H4Cl (3c), 4-C6H4Me (3d), 3-C6H4Me (3e) 4-C6H4tBu (3f)) have been synthesized by treatment of the dimeric precursor [{RuCl(μ-Cl)(η3:η3-C10H16)}2] (1) with 4 equiv of t...
In this contribution, the high-yield preparation and optical properties of some donor-acceptor butadiene dyes, generated by coupling of different 1,1-diaryl-2-propyn-1-ols with indan-1,3-dione, are presented. The reactions, which involve the initial Meyer–Schuster rearrangement of the aromatic alkynols and subsequent condensation of the resulting e...
Amide bond formation reactions are among the most important transformations in organic chemistry because of the widespread occurrence of amides in pharmaceuticals, natural products and biologically active compounds. The Beckmann rearrangement is a well-known method to generate secondary amides from ketoximes. However, under the acidic conditions co...
Owing to its biodegradable and non-toxic nature, glycerol, the main byproduct in the production of biodiesel fuel, is being actively investigated as a green reaction medium for synthetic organic chemistry. A huge number of synthetic transformations have been conducted in glycerol in recent years, showing most of them having similar or even superior...
The Binap-based hydroxyphosphine-(η6-arene)-ruthenium(II) complexes [RuX{η6:κ1(P)-PPh2-binaphthyl}{PPh2(OH)}][OTf] (X = OTf (4), Cl (5)) have been evaluated as potential catalysts for the selective hydration of nitriles to primary amides. The triflate derivative 4 proved to be the most active, being able to hydrate a large variety of aromatic, hete...
The hydration of nitrile is an atom economical route to generate primary amides of great academic and industrial significance. From an academic perspective, considerable progress has been made toward the development of transition metal catalysts able to promote this hydration process under mild conditions. In this context, with regard to activity,...
The straightforward synthesis of tethered η5-oxocyclohexadienyl Ru(II) complexes is presented. Pioneering results in catalysis show that these original half-sandwich Ru(II) complexes allow the effective isomerization of allylic alcohols under mild conditions without further additives; η5-oxocyclohexadienyl ruthenium complexes may be considered as a...
The enantioselective hydrogenation of enol esters of formula CH2═C(OBz)R with rhodium catalysts based on phosphine–phosphite ligands (P–OP) has been studied. The reaction has a broad scope, and it is suitable for the preparation of products possessing a wide variety of R substituents. For the cases where R is a primary alkyl, high catalyst activity...
The amide functionality is one of the most important functional groups in organic and biological chemistry. Classical synthetic strategies of amides involve the stoichiometric, and poor atom efficient, reaction of amines with carboxylic acid derivatives. Transition-metal-catalyzed reactions have emerged in recent years as more atom-economical and p...
John Wiley & Sons, Hoboken, 2013. 440 S., geb., 109.00 €.—ISBN 978-1118155424
A Ru(iv) catalyst able to promote the selective hydration of nitriles to amides in water, at low metal loadings and under mild conditions, is presented.
In the last few years there has been increasing interest in the use of water as a reaction medium for catalysis, and therefore in designing water-soluble transition-metal catalysts. Half-sandwich (η6-arene)-ruthenium(II) complexes are a versatile and well-known family of ruthenium compounds that exhibit a rich catalytic and coordination chemistry....
Several rhodium(I) complexes, [RhCl(COD)(PR3)], containing potentially cooperative phosphine ligands, have been synthesized and evaluated as catalysts for the selective hydration of organonitriles into amides in water. Among the different phosphines screened, those of general composition P(NR2)3 led to the best results. In particular, complex [RhCl...
An efficient, inexpensive and selective catalytic system for the industrially relevant isomerization of estragole to trans-anethole has been developed using the arene-ruthenium(II) dimer [{RuCl(μ-Cl)(η6-p-cymene)}2] in combination with P(OMe)3. As an example, using 100 mg of this complex and 38 μL of P(OMe)3 (1 equiv. per Ru), 10 mL of estragole co...
Catalytic rearrangements, isomerizations, and allylation processes of organic substrates in aqueous media are reviewed. Enhanced or completely new reactivities in comparison with those processes performed in classical organic solvents are particularly highlighted.
Going chiral! Highly enantioselective catalytic hydrogenations of enol esters 1 by using a Rh catalyst bearing a POP ligand are described (see scheme; NBD=norbornadiene). The catalytic system has a broad scope and allows the preparation of a wide range of chiral esters 2 bearing diverse alkyls or a benzyl group with high enantioselectivities. Thes...
Zwitterionic imidazolium salts bearing 3-sulfonatopropyl, and 2-pyridyl, 2-picolyl, and 2-pyridylethyl substituents have been synthesized and employed as precursors for the preparation of novel water-soluble Au(I)- and Au(III)-NHC complexes of general composition [AuCl(NHC)] and [AuCl3(NHC)] (NHC = N-heterocyclic carbene), respectively. These compl...
This chapter is intended to cover the progress made in the use of this new generation of catalysts to promote atom-economical rearrangement reactions of organic molecules. Two main families of nanocatalysts have been employed to promote rearrangement reactions: (i) those based on metal(0) nanoparticles and (ii) those based on nano-sized metal oxide...
A series of water-soluble N-protonated thiazolyl-phosphine hydrochloride salts have been synthesized and coordinated to the ruthenium(II) fragment [RuCl<sub>2</sub>(η<sup>6</sup>-p-cymene)]. The resulting complexes were evaluated as potential catalysts for the selective hydration of nitriles to primary amides in environmentally friendly aqueous med...
The structures of complexes [PdCl2{3,3'-(OH)(2)-2,2'-bipy}] (1), [PdCl2{4,4'-(OH)(2)-2,2'-bipy}] (2), [PdCl2{5,5'-(OH)(2)-2,2,-bipy}] (3) and [PdCl2{6,6'-(OH)(2)-2,2'-bipy}] (4) were determined by means of X-ray diffraction studies, employing in all cases crystals grown from DMF solutions. We have found that, depending on the exact location of the...
Iminophosphoranes R3P=NR are nitrogen analogues of phosphorus ylides that can coordinate transition metals using the lone pair on the nitrogen atom. The integration of supplementary donor sites into the iminophosphorane backbone yields polydentate ligands of increasing interest in both coordination chemistry and catalysis. Herein, a comprehensive a...
The readily available arene-ruthenium(II) complex [RuCl<sub>2</sub>(η<sup>6</sup>-C<sub>6</sub>Me<sub>6</sub>){P(NMe<sub>2</sub>)<sub>3</sub>}] (5 mol%) proved to be an efficient catalyst for the direct synthesis of primary amides from aldehydes and hydroxylamine hydrochloride (NH<sub>2</sub>OH·HCl) in water at 100 °C. The process, which requires t...
Amides are versatile building blocks in synthetic organic chemistry, present a wide range of pharmacological applications, and are used as raw materials in industry for the large-scale production of engineering plastics, detergents and lubricants. The development of green procedures for the synthesis of this relevant class of compounds from various...
Treatment of [RuCl2(η6-p-cymene){k1-(P)-PPh2(py-6-tert-amyl)}] (1a) and [RuCl2(η3: η3-C10H16){k1-(P)-PPh2(py-6-tert-amyl)}] (1b) with [AuCl(SMe2)], in dichloromethane at room temperature, resulted in the formation of the dimethyl sulfide adducts [RuCl2(η6-p-cymene)(SMe2)] (3a) and [RuCl2(η3:η3-C10H16)(SMe2)] (3b), and the Au(I) complex [AuCl{k1-(P)...
Glycerol is a non-toxic, non-hazardous, non-volatile, biodegradable, and recyclable liquid that is generated as a byproduct in the manufacture of biodiesel fuel from vegetable oils. Due to its easy availability, along with its unique combination of physical and chemical properties, glycerol has recently emerged as an economically appealing and safe...
The mononuclear arene-ruthenium(II) derivatives [RuCl<sub>2</sub>(η<sup>6</sup>-arene)(PTA-Me)] (arene = C<sub>6</sub>H<sub>6</sub> (3a), p-cymene (3b), 1,3,5-C<sub>6</sub>H<sub>3</sub>Me<sub>3</sub> (3c), C<sub>6</sub>Me<sub>6</sub> (3d)), containing the ionic phosphine ligand 1-methyl-3,5-diaza-1-azonia-7-phosphaadamantane chloride (PTA-Me), have...
The ruthenium(II) arene dimer [RuCl(mu-Cl)(eta(6)-p-cymene)(2)] readily reacted with 4 equiv of guanidines ((PrHN)-Pr-i)(2)C=NR (R = Pr-i (1a), 4-(C6H4Bu)-Bu-t (1b), 4-C6H4Br (1c), 2,4,6-C6H2Me3 (1d), 2,6-(C6H3Pr2)-Pr-i (1e)) in toluene at room temperature to generate the mononuclear complexes [RuClkappa N-2,N'-C(NR)((NPr)-Pr-i)(NHPr)-Pr-i(eta(6)-p...
The complex [Os(η6-p-cymene)(OH)IPr]OTf (1; IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolylidene; OTf = CF3SO3) reacts with benzonitrile and acetonitrile to afford the κ2-amidate derivatives [Os(η6-p-cymene){κ2O,N-NHC(O)R}IPr]OTf (R = Ph (2), CH3 (3)). Their formation has been investigated by DFT calculations (B3PWP1), starting from the model interm...
The rearrangement of aldoximes to primary amides has been studied using the readily available arene-ruthenium(II) complex [RuCl2(η6-C6Me6){P(NMe2)3}] (5 mol %) as catalyst. Reactions proceeded cleanly in pure water at 100 °C without the assistance of any cocatalyst, affording the desired amides in high yields (70-90%) after short reaction times (1-...
Metal-catalysis in aqueous medium has led in recent years to the development of a huge number of new and greener synthetic methodologies in organic chemistry. Also, the search for organic reactions that proceed with efficiency, selectivity and atom economy has emerged as a prime goal in synthetic chemistry. Among the organic processes that take pla...
Neutral arene-ruthenium(II) complexes [RuCl2(η6-arene){κ1-(P)-PPh2py}] and [RuCl2(η6-arene){κ1-(P)-PPh2(py-4-NMe2)}] (arene = benzene, p-cymene, mesitylene, hexamethylbenzene) have been synthesized and studied as potential catalysts for the selective hydration of nitriles to amides using benzonitrile as a model substrate. The effectiveness of these...
A novel water-soluble Au(III)-NHC complex has been synthesized and successfully applied in the intramolecular cyclization of γ-alkynoic acids into enol-lactones under biphasic toluene/water conditions, thus representing a rare example of an active and selective catalyst for this transformation in aqueous media. Remarkably, competing alkyne hydratio...
A variety of both terminal and internal alkynols is isomerized using the readily accessible vanadate complex.
The rapid growth of the biodiesel industry has led to a large surplus of its major byproduct, i.e. glycerol, for which new applications need to be found. In line with the increasing interest by the chemical community in the use of “green” solvents, an innovative way to revalorize glycerol has seen the light in recent years, i.e. its use as environm...
A catalytic system consisting of the ruthenium(II) complex [Ru(η³-2-C3H4Me)(CO)(dppf)][SbF6] (dppf=1,1'-bis(diphenylphosphino)ferrocene) and trifluoroacetic acid has been used to promote the coupling of secondary propargylic alcohols with 6-chloro-4-hydroxychromen-2-one. The reactions afforded unusual 2-methylene-2,3-dihydrofuro[3,2-c]chromen-2-one...
The conjugate addition of arylboronic acids to α,β-unsaturated carbonyl compounds in water under air has been studied using a series of palladium(II) derivatives containing symmetrically disubstituted-2,2′-bipyridine ligands. Among them, best results were obtained with complex [PdCl2{3,3′-(OH)2-2,2′-bipy}] (2a), which selectively provides the desir...
The catalytic hydration of nitriles into amides, in water under neutral conditions, has been studied using a series of arene-ruthenium(II) derivatives containing the commercially available and inexpensive ligand tris(dimethylamino)phosphine. Among them, best results were obtained with complex [RuCl<sub>2</sub>(η<sup>6</sup>-C<sub>6</sub>Me<sub>6</s...
Glycerol, a biodegradable and virtually non-toxic chemical, can be used as a green solvent and hydrogen donor in the ruthenium-catalyzed reduction of allylic alcohols, a tandem process that involves the initial redox-isomerization of the allylic alcohol and subsequent transfer hydrogenation of the resulting carbonyl compound. Among the different ru...
A general mechanism to rationalize Ru(IV) -catalyzed isomerization of the C=C bond in O-allylic substrates is proposed. Calculations supporting the proposed mechanism were performed at the MPWB1K/6-311+G(d,p)+SDD level of theory. All experimental observations in different solvents (water and THF) and under different pH conditions (neutral and basic...
An efficient and practical synthesis of the non-steroidal anti-inflammatory drug (NSAID) ibuprofenamide by catalytic hydration of 2-(4-isobutylphenyl)propionitrile is described. The readily accessible arene-ruthenium(II) complex [RuCl<sub>2</sub>(η<sup>6</sup>-C<sub>6</sub>Me<sub>6</sub>){P(NMe<sub>2</sub>)<sub>3</sub>}] is used as catalyst, pure w...
Treatment of 2,2'-bis(allyloxy)-1,1'-binaphthyls with the first-generation Grubbs' carbene under MW-irradiation results in the formation of new polycyclic spiro-enones through an unprecedented RCM/Claisen sequence.
The ability of the bis(allyl)-ruthenium(IV) complex [{RuCl(µ-Cl)(η: η-C10H16)}2] (C10H16=2,7-dimethylocta-2,6-diene-1,8-diyl) to promote intermolecular [2+2+2] alkyne cyclotrimerization reactions in aqueous media under microwave (MW) irradiation has been evaluated. Advantages and disadvantages of using MW vs. conventional thermal heating are discus...
The rapid growth of the biodiesel industry has led to a large surplus of its major byproduct, i.e. glycerol, for which new applications need to be found. Research efforts in this area have focused mainly on the development of processes for converting glycerol into value-added chemicals and its reforming for hydrogen production, but recently, in lin...
Several ruthenium(IV) complexes have been tested as potential catalysts for the isomerization of estragole into anethole using water and glycerol as alternative green reaction media. Best results in terms of activity and E-selectivity were obtained with the dimeric species [{RuCl(µ-Cl)(η3:η3-C10H16)}2] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl)...