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The synthesis of spiro compounds featuring seven- and six-membered rings in the spirobicyclic motif is successfully achieved through a cascade process encompassing a rhodium(I)-catalyzed cycloisomerization followed by a highly selective Diels-Alder homodimerization. The scope of the reaction is analyzed based on a series of synthetic substrates, and control experiments and DFT calculations led us to justify the exquisite degree of selectivity observed We are grateful for financial support from the Ministerio de Ciencia e Innovación (PID2020-113711GB-I00 MCIN/AEI/ 10.13039/501100011033), the Generalitat de Catalunya (Project 2017-SGR-39), and the UdG for an IF predoctoral grant to J.V. Open Access funding provided thanks to the CRUE-CSIC agreement with ACS

[2+2+2] Cycloaddition reaction is a captivating process that assembles six-membered rings from three unsaturations with complete atom economy. Of the multiple transition metals that can be used to catalyze this reaction, rhodium offers many advantages. These include high activity and versatility, but especially the ability to easily tune the reactivity and selectivity by the modification of the ligands around the metal. In this personal account, we summarize our endeavours in the development of efficient and sustainable [2+2+2] cycloaddition reactions to prepare products of interest, develop conditions in which the catalyst can be recovered and reused, and understand the mechanistic details that govern the selectivity of the processes This research was funded by the Ministerio de Ciencia e Innovación (projects CTQ2017-85341-P, PID2020-113711GB-I00 MCIN/AEI/10.13039/501100011033) and the Generalitat de Catalunya (Project 2017-SGR-39)

We previously demonstrated that treatment with BemA (bempedoic acid), an inhibitor of ATP citrate lyase, significantly reduces fatty liver in a model of liver steatosis (HFHFr-female Sprague-Dawley rat fed a high-fat high-fructose diet). Since the hepatic production of the gasotransmitter H2S is impaired in liver disorders, we were interested in determining if the production of H2S was altered in our HFHFr model and whether the administration of BemA reversed these changes. We used stored liver samples from a previous study to determine the total and enzymatic H2S production, as well as the expression of CBS (cystathionine β-synthase), CSE (cystathionine γ-lyase), and 3MST (3-mercaptopiruvate sulfurtransferase), and the expression/activity of FXR (farnesoid X receptor), a transcription factor involved in regulating CSE expression. Our data show that the HFHFr diet reduces the total and enzymatic production of liver H2S, mainly by decreasing the expression of CBS and CSE. Furthermore, BemA treatment restored H2S production, increasing the expression of CBS and CSE, providing evidence for the involvement of FXR transcriptional activity and the mTORC1 (mammalian target of rapamycin1)/S6K1 (ribosomal protein S6 kinase beta-1)/PGC1α (peroxisome proliferator receptor gamma coactivator1α) pathway. Keywords: FXR; NAFLD; PGC1α; S6K1; fructose; high-fat diet; mTORC1.

A novel methodology to transform C60 into a variety of open-cage fullerene derivatives by employing rhodium(I) catalysis has been developed. This transformation encompasses a partially intermolecular [2+2+2] cycloaddition reaction between diynes 1 and C60 to deliver a cyclohexadiene-fused fullerene, which concomitantly undergoes a formal [4+4]/retro-[2+2+2] rearrangement to deliver open-cage fullerenes 2. Most notably, this process occurs without the need of photoexcitation. The complete mechanism of this transformation has been rationalized by DFT calculations, which indicate that, after [2+2+2] cycloaddition, the cyclohexadiene-fused intermediate evolves into the final product through a Rh-catalyzed di-π-methane rearrangement followed by a retro-[2+2+2] cycloaddition. The obtained open-cage fullerenes can be derivatized by Suzuki-Miyaura cross-coupling or subjected to ring expansion to deliver a 12-membered ring orifice in the fullerene structure. Overall, the methodology presented constitutes a straightforward entry to functional open-cage C60 fullerene derivatives by employing catalytic methods.

Allene-(E)-ene-yne N-tosyl-tethered substrates 3 a–3 h were efficiently prepared and their rhodium-catalyzed [2+2+2] cycloaddition reactions were evaluated. The cycloadditions are chemoselective as only the proximal double bond of the allene reacted to afford exocyclic double bonds in the fused-tricyclic scaffolds. The stereoselectivity depended on the catalytic system used. Reactivity between allene, alkene, and alkyne was studied for the first time by density functional theory calculations. This mechanistic study determines the order in which the unsaturated groups take part in the catalytic cycle Financial support fro m the Spanish Ministry of Educatio n and Science (MINECO) (Project No. CTQ2014-54306-P and CTQ2015-64436-P), the DIUE of the Generalitat de Catalunya (Project No.: 2014SGR931, pre-doctoral grant to D.C. and ICREA Academia 2014 prize to MS), and the FEDER fund (European Fund for Regional Development) for grant UNGI08-4E-801 is gratefully acknowledged

A novel methodology to transform bisallenes into a variety of polycyclic derivatives employing rhodium(I) catalysis has been developed. This transformation encompasses an intramolecular Rh-catalyzed cycloisomerization of bisallenes 1 to deliver a reac-tive cycloheptadiene, which concomitantly undergoes a regioselective [4+2] cycloaddition with alkenes. A complete mechanistic study of this transformation has been undertaken including DFT calculations. Overall, the methodology presented here constitutes a new and straightforward entry to polycyclic dihydroazepine and dihydrooxepine derivatives employing catalytic methods We are grateful for the financial support by the Spanish Ministry of Economy and Competitivity (MINECO) (Projects CTQ2017- 85341-P and CTQ2017-83587-P, FI predoctoral grant to A.A., RyC contract RYC2012-11112 to A.L.), the Generalitat de Catalunya (Project 2017-SGR-39, Xarxa de Referència en Química Teòrica i Computacional, ICREA Academia 2014 prize for M.S.) and UdG for IF predoctoral grant to J.V

N-Tosylhydrazone-yne-ene substrates are satisfactorily prepared and their cyclization under rhodium catalysis is evaluated. A cascade process involving rhodium vinyl carbene formation – through carbene/alkyne metathesis – and cyclopropanation has been developed to stereoselectively afford vinylcyclopropanes We are grateful for the financial support by the Spanish Ministry of Education and Science (MINECO) (Project CTQ2014-54306-P) and the DIUE of the Generalitat de Catalunya (Project 2014-SGR-931 and FI predoctoral grant to >.T.)

High enantioselection is obtained in α-amination of acyclic β-keto esters in the presence of lanthanide triflates and pybox ligands. The Eu3+ complexes proved more active than those with Yb3+ and La3+ and high dependence of ee on the type and steric bulk of the ester group was observed. Excellent results were achieved using a combination of europium triflate with ligand L4 (diphenyl-pybox). Preparation of ternary complexes (8) [(L4)(β-keto ester enolate)Ln (OTf)2] was accomplished. Complexes 8 and [(L4)(β-keto ester)Ln (OTf)2]+, identified by ESI-MS, are proposed as key intermediates of the α-amination reaction.

One of the most important threats to global human health is the increasing incidences of metabolic pathologies (including obesity, type 2 diabetes and non-alcoholic fatty liver disease), which is paralleled by increasing consumptions of hypercaloric diets enriched in simple sugars. The challenge is to identify the metabolic pathways affected by the excessive consumption of these dietary components when they are consumed in excess, to unravel the molecular mechanisms leading to metabolic pathologies and identify novel therapeutic targets to manage them. Mechanistic (mammalian) target of rapamycin (mTOR) has emerged as one of the key molecular nodes that integrate extracellular signals, such as energy status and nutrient availability, to trigger cell responses that could lead to the above-mentioned diseases through the regulation of lipid and glucose metabolism. By activating mTOR signalling, excessive consumption of simple sugars (such as fructose and glucose), could modulate hepatic gluconeogenesis, lipogenesis and fatty acid uptake and catabolism and thus lipid deposition in the liver. In the present review we will discuss some of the most recent studies showing the central role of mTOR in the metabolic effects of excessive simple sugar consumption.

The electronic and steric factors that favour the formation of 1,2,4- and 1,3,5-regioisomers in the intermolecular [2+2+2] cyclotrimerisation of terminal alkynes are not well understood. In this work, this problem was analysed from a theoretical and experimental point of view. Density functional theory (DFT) calculations of the [2+2+2] cyclotrimerisation of p-X-substituted phenylacetylenes (X = H, NO2, and NH2) catalysed by [Rh(BIPHEP)]+ were carried out to determine the reaction mechanism in each case and analyse the effect that the electronic character of the substituents has on the regioselectivity. For the rate-determining step corresponding to the oxidative coupling leading to the rhodacyclopentadiene intermediate, we have taken into account two reaction pathways: the reaction pathway with the lowest energy barrier and the reaction pathway through the most stable transition state (Curtin-Hammett pathway). Our results show that the theoretical results conform experimental outcomes for different p-X-substituted phenylacetylenes (X = NO2, F, H, Me, tBu, OMe, NMe2) only when the Curtin-Hammett reaction pathway is considered. A fairly good correlation has been obtained between the electronic nature of the substituents (as expressed by the Hammett σpara constant values) and the regioisomeric ratios experimentally obtained and computationally predicted Financial support from the Spanish Ministry of Economy and Competitivity (MINECO) (Project No. CTQ2017-85341-P) and the DIUE of the Generalitat de Catalunya (Project No. 2017SGR39 and ICREA Academia 2014 to M. S.) are acknowledged. Thanks are due to the Generalitat de Catalunya for FI predoctoral grants to Ò.T., M.F. and À.D.-J. The EU under the FEDER grant UNGI10-4E-801 has also funded this research

We report the enantioselective, lateral deprotonation of ortho-protected or functionalized tertiary N,N-dialkyl aryl O-carbamates 5-7 (Scheme 2 ) and meta-protected carbamates 14, 15, and 20 (Schemes 5 and 7 ) by s-BuLi/(-)-sparteine and subsequent quench with a variety of electrophiles to give products 11-13 and 16, 17, and 21 in yields up to 96% and enantiomeric ratios up to 99:1. The influence of organolithium reagents, ratio of organolithium/(-)-sparteine pair versus N,N-dialkyl aryl O-carbamate starting materials, temperature, solvents, electrophiles, substituents located ortho or meta to the O-carbamate moiety, and O-carbamate N-substituents was investigated. The identical absolute configuration of the stereogenic center of the major enantiomers of the products, as established by single-crystal X-ray analysis for substrates (S)-11c, (S)-19, and (S)-21a, provides evidence for a consistent stereochemical course in the enantioselective deprotonation. Mechanistic investigations, including an estimate of the configurational stability of the benzyllithium species 9 (starting from 12e; Scheme 8 ) and 23 (starting from 17e; Scheme 9 ), both derived by tin-lithium exchange, and 24 (starting from 20; Scheme 9 ) are reported. The experimental results, together with semiempirical molecular orbital calculations (PM3/SMD), are consistent with a process in which enantioinduction occurs in the deprotonation step (Scheme 11 ).

Financial support from the Spanish Ministerio de Ciencia e Innovacion (MICINN) (grant numbers CTQ2011-23121, CTQ2009-07881, CTQ2012-32436, CTQ2011-22649, CSD2007-00006) and by the Generalitat de Catalunya (grant numbers 2009SGR637, 2009SGR1441, and predoctoral grant to M. Fernandez) is acknowledged. M. Ferre thanks the Universitat Autonoma de Barcelona for a predoctoral scholarship

An efficient method for the synthesis of N-arylated pyridazinones from potassium 2-furantrifluoroborate and aryldiazonium salts is described. The reaction was run in water at 0-5 °C in short reaction times and without any catalyst or additive. A mechanistic proposal is made based on the experimental data and DFT calculations We thank MINECO (Projects CTQ2011-23121, 23156, and CTQ2012-32436) and the Generalitat de Catalunya (Project 2009SGR637, ICREA Academia for M.S.) for financial support

Aryl-heteroaryl and heteroaryl-heteroaryl compounds are obtained through the Suzuki-Miyaura cross-coupling reactions between diazonium salts and potassium trifluoroborates using PdCl2(CH3CN)2 as the catalyst in water and in the absence of any additive, ligand or base. In addition, the same mild catalytic system is effective for the Matsuda-Heck reaction between several monoolefins with aryldiazonium salts Financial support from MICINN (CTQ2011-23121) of Spain and 'Generalitat de Catalunya' (2009SGR637) is acknowledged

The functionalization of fullerenes helps to modulate their electronic and physicochemical properties, generating fullerene derivatives with promising features for practical applications. Herein, DFT is used to explore the attachment of a cyclohexadiene ring to C60 through a rhodium-catalyzed intermolecular [2+2+2] cycloaddition of C60 and acetylene. All potential reaction paths are analyzed and it can be concluded that the [2+2+2] cycloaddition of C60 and two acetylene molecules catalyzed by [RhCl(PPh3)3], yielding a cyclohexadiene ring fused to a [6,6] bond of C60, is energetically feasible Funded by: Ministerio de Economía y Competitividad. Grant Number: CTQ2014-54306-P; Ministerio de Economia y Competitividad (MINECO). Grant Number: RYC2012-11112 Generalitat de Catalunya. Grant Numbers: 2014SGR931, ICREA Academia 2014 European Union. Grant Number: UNGI10-4E-801

The acyclic 4,9-bis(4-tolylsulfonyl)-4,9-diazadodeca-1,11-dien-6-yne (1) and 4,9-bis(4-tolylsulfonyl)-4,9-diazatrideca-1,(E)-6-dien-11-yne (2), which differ in the sequence of the two ene and one yne functions in the chain, have been reacted with 1 and 2 equiv of Ni(cod)2. The reaction with 1 equiv of Ni(cod)2 affords the mononuclear trigonal-planar nickel(0) complexes 3 and 5. These react with a further 1 equiv of Ni(cod)2 by addition of a Ni(cod) entity to give the dinuclear derivatives 4 and 6. While 3 forms a mixture of isomers C2-3 and Cs-3 in solution, C2-3 is exclusively present in the crystal, where it is packed in parallel columns. Complex 6 crystallizes as a spherulite. Complexes 3-6 have been characterized by NMR and single-crystal X-ray structure analysis, and a detailed conformational analysis is given We thank Mrs. D. Bartels for recording and evaluating the NMR spectra of 2, 5, and 6 and Mrs. W. Gamrad for skillful technical assistance. The project was funded by the program Acciones Integradas Hispano-Alemanas between Germany (DAAD, BMBF) and Spain (MICINN, Spanish Ministry of Science and Innovation, project AIB2010DE-00262). Financial support from the MICINN (project CTQ2011-23121) and the Generalitat de Catalunya (project 2009SGR637) is also gratefully acknowledged

Fluorous aryl compounds are obtained through the arylation of different electron-rich and electron-poor olefins with an arenediazonium salt bearing a fully fluorinated octyl-ponytail at the para position. The Matsuda–Heck reactions are catalyzed by Pd(OAc)2 or 4-hydroxyacetophenone oxime-derived palladacycle as efficient sources of Pd nanoparticles, with loadings of 1 mol % Pd, at room temperature, in methanol and without the need to add external base.

In this study we analyze a series of intramolecular [2+2+2] cycloadditions of enediynes catalyzed by the Wilkinson’s complex with the B3LYP method. We are interested in the changes observed in the ...

The combination of cationic rhodium(I) complexes with N-phosphino tert-butylsulfinamides (PNSO) ligands is efficient for catalytic intra- and intermolecular [2+2+2] cycloaddition reactions. PNSO ligands are a new class of chiral bidentate ligands, which have the characteristic of combining the easily accessible sulfur chirality with the coordinating capacity of phosphorous. Cycloaddition of open-chained and macrocyclic E-enediynes with these chiral complexes have proved to be highly efficient in terms of yields, giving moderate enantiomeric excesses of the corresponding cyclohexadiene derivatives. In addition Rh(I)/PNSO complexes catalyzed the intermolecular cycloaddition of diynes with monoalkynes in mild reaction conditions and short reaction times.

Rhodium(I)-catalyzed [2+2+2] cycloaddition reactions of N-tosyl-, carbon-, and oxygen-tethered cyanodiynes in a completely intramolecular fashion have been optimized to afford highly functionalized pyridines by conventional and/or microwave heating. Microwaves have been shown to enhance the process by allowing the reaction to be conducted effectively in short reaction times. The methodology has been extended for the synthesis of bipyridines, either by treating a cyanodiyne with an appended pyridine or by conducting a double [2+2+2] cycloaddition reaction on a dicyanotetrayne scaffold. The choice of the solvent in the microwave heating reaction has been shown to be crucial for the success of the process.

In this work we report density functional calculations at the B3LYP level of the [2+2+2] intermolecular cyclotrimerization of three acetylene molecules catalyzed by Wilkinson’s catalyst. This process corresponds to the simplest [2+2+2] cyclotrimerization reaction. The results obtained show that this reaction is thermodynamically very favorable and that the rate-determining step is the initial oxidative coupling between two acetylene molecules with a relatively low Gibbs free energy barrier of 19.8 kcal·mol−1. The energy profile derived from the real [RhCl(PPh3)3] Wilkinson’s catalyst is compared with that obtained with a model of the catalyst in which the PPh3 ligands have been substituted by the smaller and computationally less expensive PH3 molecules. Our results show that, at least for this reaction, this substitution has little influence on the thermodynamics obtained, while the barrier of the rate-determining step is somewhat increased (about 5 kcal·mol−1) in the model system. These results justify t...

Rhodium complexes of N-heterocyclic carbenes (NHC) [RhCl(cod)(NHC)], [cod=1,5-cyclooctadiene, NHC = 1,3-diisopropylimidazolin-2-ylidene, and NHC = 1,3-dimesitylimidazolin-2-ylidene] are tested for intra- and partially intramolecular [2+2+2]-cycloaddition reactions demonstrating their effectiveness in this kind of process. This is the first use of a rhodium-NHC complex in a [2+2+2]-cycloaddition reaction of three alkynes. ESI-MS has been used to detect oxidative addition intermediates using rhodium NHC as the catalytic system.

Two palladium complexes containing triene-coordinated ligands, 3 and 4, open-chain analogues of the macrocyclic palladium(0) complexes of type 1, have been synthesized. A comparative study of both open-chain and macrocyclic complexes has been carried out, based on a NMR and X-ray structural analysis, a DSC thermal behavior assessment, and a catalytical activity evaluation in the arenediazonium and organotrifluoroborate cross-coupling Suzuki−Miyaura reaction. The 1,6,11-triene sequence has been revealed to be crucial in the great stability of this family of palladium(0) complexes.

Selective and efficient preparation of a new chiral dipalladium(0) complex with an olefinic macrocyclic ligand named (E,E,E,E,E,E)-1,6,11,16,21,26-hexakis[(4-methylphenyl)sulfonyl]-1,6,11,16,21,26-hexaazacyclotriaconta-3,8,13,18,23,28-hexaenedipalladium(0) (5) is reported. Dinuclear palladium(0) complex 5 has been fully characterized by means of NMR spectroscopy and X-ray diffraction analysis.

High enantioselection is obtained in Michael additions of cyclic beta-ketoesters in the presence of lanthanium triflates and (S,S)-ip-pybox. Intermediates based on simultaneous coordination of the lanthanide to both (S,S)-ip-box and beta-ketoester (in keto and enolate forms) are detected by means of ESI mass spectrometry and NMR experiments, and a possible mechanism is proposed through theoretical calculations.

Fifteen-membered triolefinic macrocyclic palladium(0) complex 1, (E,E,E)-1-ferrocenylsulfonyl-6,11-bis[(4-methylphenyl)sulfonyl]-1,6,11-triazacyclopentadeca-3,8,13-trienepalladium(0), is an active and recoverable catalyst for Suzuki–Miyaura cross-couplings between arenediazonium salts and potassium organotrifluoroborates. The reactions were performed under aerobic conditions at room temperature and without added base. Use of electrospray ionization mass spectrometry (ESI-MS) allowed the direct detection and identification of several intermediates, which furthers the study of the mechanistic aspects of the Suzuki–Miyaura reaction. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

The allylic substitution of allylic acetates by sodium para-toluenesulfinate in aqueous media was catalyzed by [(η3-allyl)PdCl]2 associated with [(HOCH2CH2NHCOCH2)2NCH2]2. High yields could be obtained but the recycling of the catalytic system proved to be weakly effective. ESI-MS analysis has led to the suggestion of a possible catalytic cycle involving a PdIV intermediate.

A novel type of chiral and stable palladium(0) complexes of polyunsaturated aza-macrocyclic ligands were prepared and fully characterized by means of NMR spectroscopy and X-ray diffraction. Fifteen-membered alkene−alkyne type ligands as well as 20- and 25-membered polyolefinic ligands showed a preference for tricoordination with the metal. The stereochemical complexity of these complexes is related to the different isomers that can be formed by complexation of the metal to either of the two faces of each of the olefins involved. The palladacyclopropane formulation of the palladium−olefin interaction offers a clear picture of the stereogenicity of the olefin carbon atoms when they are coordinated to the metal. The preorientation of the macrocyclic ligand and the prepositioning of the olefinic bonds for complex formation facilitated by six-membered chelate rings explain the stability of the structures. The conformation of the palladacyclohexanic rings is found to be crucial in the stereoisomers formed. Thes...

This work deals with the evaluation of a synthesized 15-membered triolefinic azamacrocycle containing a NH group, (E,E,E)-1,6-bis(p-tolylsulfonyl)-1,6,11-triazacyclopentadeca-3,8,13-triene (R2NH), for the selective extraction of palladium and platinum from aqueous chloride matrices prior their analysis by ICP-AES. The optimal conditions for liquid–liquid experiments have been evaluated, with special emphasis given to the selection of the organic solvent and the optimal aqueous chloride concentration for the extraction of PdCl42− and PtCl62−. The selective transport and separation of palladium(II) from a mixture of Pd(II) and Pt(IV) was accomplished by means of a supported liquid membrane system containing the macrocycle as carrier dissolved in anethol and 0.5 M thyocianate solution as stripping solution. A C18 cartridge has been activated with the reagent R2NH in order to test the feasibility of achieving the preconcentration of palladium solutions. Enrichment factors close to the theoretical ones were obtained with the designed system and using thiourea as eluting solution.

A stepwise preparation of a series of nitrogen-containing 25-membered pentaolefinic macrocycles is presented. The corresponding arenesulfonamides and trans-1,4-dibromo-2-butene served as precursors for the synthesis.

Membered macrocycles (E,E,E)-1,6,11-tris(arenesulfonyl)-1,6,11-triazacyclopentadeca-3,8,13-trienes (1) are prepared from a- renesulfonamides and trans-1,4-dibromo-2-butene. Macrocycles 1 coordinate palladium(0), platinum(0), and silver(I). The palladium complexes are useful and reutilizable catalysts or precatalysts in Suzuki cross-couplings, butadiene telomerizations, hydroarylation of alkynes, and in the Heck reaction. Structurally related macrocycles are also available by similar synthetic procedures. � 2004 Elsevier B.V. All rights reserved.

Allylic substitution of PhCH(OAc)CHCHPh by CH2(COMe)2 in a basic MeOH/H2O mixture could be achieved in the absence of a palladium catalyst and lead to a mixture of PhCH(CH(COMe)2)CHCHPh and PhCH(OMe)CHCHPh in 40% and 55% yields, respectively. The process is induced by water, and nucleophilic attack addition occurred on a stabilized carbocation as the intermediate. Addition of a catalytic amount of PdCl2(CH3CN)2 did not accelerate the reaction but improved the selectivity, and PhCH(CH(COMe)2)CHCHPh was then obtained in 92% yield while PhCH(OMe)CHCHPh was observed in trace amounts. An ESI-MS analysis of the reaction mixture led us to assume that a palladium acetylacetonate complex is involved in the formation of PhCH(CH(COMe)2)CHCHPh.

We report a flexible approach to the total synthesis of 4,5-dioxoaporphines based on the palladium(0) catalyzed Suzuki cross-coupling of phenylboronic acids with sterically hindered 2-bromo phenyl acetates or bromo phenyl acetamides, followed by sequential bicyclization of biarylacetamides promoted by oxalyl chloride/Lewis acid. The reduction of 4,5-dioxoaporphines provides a chemoselective entry to aporphines, dehydroaporphines and 4-hydroxy-dehydroaporphines. A three-steps total synthesis for (±)-O,O′-dimethylapomorphine from readily accessible precursors is also reported.

Selective and efficient preparation of a new type of nitrogen-containing 15-membered triacetylenic macrocycles named 1,6,11-tris(arylsulfonyl)-1,6,11-triazacyclopentadeca-3,8,13-triynes (1) (Ar1 = Ar2 = Ar3 = 4-methylphenyl, 1aaa; Ar1 = Ar2 = 4-methylphenyl, Ar3 = ferrocenyl, 1aab) has been achieved. Macrocycle 1aaa forms a very stable complex with Pd0, being the first palladium(0) complex with a macrocyclic triyne. The three triple bonds in 1aaa are responsible for the complexation. The X-ray structures of both the ligand 1aaa and its Pd0 complex are presented. Furthermore, compound 1aaa undergoes cycloisomerization into the corresponding 2,5,8-tris[(4-methlphenyl)sulfonyl]-2,5,8-triazatrindane, 11aaa, when treated with Pd(PPh3)4 in refluxing toluene.

Molecular structures featuring two and three triolefinic 15-membered macrocycles of type 2 as well as their homo- and heterometallic complexes of palladium(0) and platinum(0) (5, 7) have been synthesized from 2,4,6-trichloro-1,3,5-triazine, 1. The strategy employed allows easy preparation of heterobimetallic complexes in a controlled manner. Several mass spectrometry techniques are useful to identify these complexes.

The reaction of diyne arylsulfonyl hydrazone substrates under rhodium(I)/BINAP catalysis gives access to sulfonated azacyclic frameworks in a highly enantioselective manner. This new cascade process considerably increases the molecular complexity by generating two C-C bonds, one C-S bond, and one C-H bond. Theoretical calculations, competitive experiments, and deuterium labeling have jointly been used to propose a mechanism that accounts for the reaction. The mechanism involves the formation of vinyl rhodium carbenoids, hydride migratory insertion, and intermolecular stereoselective nucleophilic attack. The last two steps are the key to the stereoselectivity of the process La reaccio catalitzada per rodi(I)/BINAP de substrats contenint dos alquins i una sulfonilhidrazona permet sintetitzar compostos nitrogenats amb un grup sulfona de forma altament enantioselectiva. Aquest nou proces en cascada augmenta considerablement la complexitat molecular ja que genera dos enllacos CC, un enllac CS i un enllac CH. Sha proposat un mecanisme per al proces desenvolupat en base als resultats obtinguts mitjancant calculs DFT, experiments de competicio i marcatge amb deuteri. El mecanisme involucra la formacio dun vinilcarbenoid de rodi, una insercio migratria dhidrur i un atac nucleofilic intermolecular estereoselectiu. Els dos darrers passos son claus per a lenantioselectivitat del proces This research was funded by the Spanish Ministry of Education and Science (MINECO) (CTQ2014-54306-P and CTQ2012-32436) and the DIUE of the Generalitat de Catalunya (2014SGR931, ICREA Academia 2014 to M.S., and FI predoctoral grant to O.T.). M.S. acknowledges funding through the European Union (EU) FEDER fund (UNGI10-4E-801)

Treatments with high doses of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors may induce the expression of sterol regulatory element binding protein (SREBP)-target genes, causing different effects from those attributed to the reduction of hepatic cholesterol content. The aim of this study was to investigate the effects of high doses of statins on the key enzymes involved in VLDL production in normolipidemic rats. To examine whether the effects caused by statin treatment are a consequence of HMG-CoA reductase inhibition, we tested the effect of atorvastatin on these enzymes in mevalonate-fed rats. Atorvastatin and simvastatin enhanced not only HMG-CoA reductase but also the expression of the SREBP-2 gene itself. As a result of the overexpression of SREBP-2 caused by the statin treatment, genes regulated basically by SREBP-1, as FA synthase and acetyl-coenzyme A carboxylase, were also induced and their mRNA levels increased. DAG acyltransferase and microsomal TG transfer protein mRNA levels as well as phosphatidate phosphohydrolase activity were increased by both statins. Simvastatin raised liver cholesterol content, ACAT mRNA levels, and CTP:phosphocholine cytidylyltransferase activity, whereas it reduced liver DAG and phospholipid content. Mevalonate feeding reversed all changes induced by the atorvastatin treatment. These results show that treatment with high doses of statins induces key enzymes controlling rat liver lipid synthesis and VLDL assembly, probably as a result of SREBP-2 overexpression. Despite the induction of the key enzymes involved in VLDL production, both statins markedly reduced plasma TG levels, suggesting that different mechanisms may be involved in the hypotriglyceridemic effect of statins at high or low doses.

A series of 15-membered triolefinic macrocycles containing ferrocenyl groups and their palladium(0) complexes have been synthesized and characterized. Their catalytic activity has been demonstrated in Suzuki-type cross-coupling and in the Heck reaction. Their redox properties have been investigated by means of cyclic voltammetry.

An efficient method for the synthesis of N-arylated pyridazinones from potassium 2-furantrifluoroborate and aryldiazonium salts is described. The reaction was run in water at 0–5 °C in short reaction times and without any catalyst or additive. A mechanistic proposal is made based on the experimental data and DFT calculations.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry allowed the direct determination of the extent of macrocyclic and linear oligomer formation in the palladium(0)-catalyzed allylation of highly acidic and non-nucleophilic arenesulfonamides, sulfamide, and cyanamide. Palladium-containing 15-membered-ring macrocyclic compounds gave unusual [M - H](+) ions besides [M + Na](+) and [M + K](+) adducts. Copyright 1999 John Wiley & Sons, Ltd.

Arenesulfonamides, sulfamide, and cyanamide are efficiently allylated using allylic carbonates under Pd(0)-catalysis. N -Arenesulfonyl-2,5-dihydropyrroles are obtained by ruthenium-mediated ring closing metathesis of the corresponding N -diallylated compounds. A stereochemical study of the reactions of ethyl cis -(5-methyl-2-cyclohexenyl) carbonate with 2,4,6-triisopropylphenylsulfonamide was performed, clean overall retention of configuration being found with bidentate phosphines.