Javier Pérez-Castells

• full professor at University Foundation San Pablo CEU

This review highlights recent advances in the hydrofunctionalisation of cyclopropenes through the formation of carbon–heteroatom bonds for the synthesis of polysubstituted cyclopropanes.

Cyclopropyl carboxylates are essential building blocks in biological and medicinal chemistry. However, their accessibility is severely limited by the need to pre-synthesise highly reactive cyclopropane derivatives. Herein, we report an...

Intramolecular Diels-Alder vinylarene reaction (IMDAV) is a [4 + 2] cycloaddition that employs styrene derivatives as conjugated dienes, whose poor reactivity arises from the required loss of aromaticity, which is recovered by a subsequent [1,3]-H shift. Herein, we describe the use of cyclopropene as a dienophile, harnessing its strain energy to dr...

Influenza virus infection remains a threat to human health since viral hemagglutinins are constantly drifting, escaping infection and vaccine-induced antibody responses. Viral hemagglutinins from different viruses display variability in glycan recognition. In this context, recent H3N2 viruses have specificity for α2,6 sialylated branched N-glycans...

Influenza virus infection remains a threat to human health since viral hemagglutinins are constantly drifting, escaping infec-tion and vaccine-induced antibody responses. During antigenic drift H3 hemagglutinins have evolved to recognize a2,6 sialylated branched N-glycans with long glycan chains with at least three N-acetyllactosamine units (tri-La...

A one pot alkenylation followed by a stereoselective Alder-ene cycloisomerization of cyclopropenes give (aza)spiro[2.4]heptanes and spiro[2.5]octanes in high yields. Total trans diastereoselectivity is achieved for spiro[2.4]heptanes if the cyclopropene is monosubstituted in C3. When an α,β-unsaturatedcarbonyl-containing bromide is used, an alterna...

High-fat diets enriched with lauric acid (SOLF) do not enhance leptin production despite expanding white adipose tissue (WAT). Our study aimed at identifying the influence of SOLF vs. oleic acid-enriched diets (UOLF) on the autoparacrine effect of leptin and was carried out on eight-week-old mice consuming control chow, UOLF or SOLF. Phosphorylatio...

The synthesis of amides from thiols through a cobalt-catalyzed aminocarbonylation is shown. After optimizing all the reaction parameters, the methodology makes possible the obtention of amides with variable yields, while competing reactions such as the formation of disulfides and ureas can be limited. The process works well with aromatic thiols wit...

Cyclopropanated iminosugars have a locked conformation that may enhance the inhibitory activity and selectivity against different glycosidases. We show the synthesis of new cyclopropane-containing piperidines bearing five stereogenic centers from natural amino acids l-serine and l-alanine. Those prepared from the latter amino acid may mimic l-fucos...

Synthesis of four iminosugars fused to a cyclopropane ring is described using l-serine as the chiral pool. The key steps are large-scale preparation of an α,β-unsaturated piperidinone followed by completely stereoselective sulfur ylide cyclopropanation. Stereochemistry of compounds has been studied by nuclear Overhauser effect spectroscopy (NOESY)...

Continuous flow reactors form part of a rapidly growing research area that has changed the way synthetic chemistry is performed not only in academia but also at the industrial level. This Review highlights the most recent advances in cycloaddition reactions performed in flow systems. Cycloadditions are atom‐efficient transformations for the synthes...

A new synthesis of treprostinil is described using a plug flow reactor in two of the key steps. First, a Claisen rearrangement reaction is described in scaled flow at multigram amounts. Yields and selectivity of this step is sharply improved from previous syntheses. Second, the key Pauson-Khand reaction in flow is described under catalytic conditio...

The reaction of ene-cyclopropenes with Cp*RuCl(cod) leads to alkenyl bicyclo[3.1.0]hexane, bicy-clo[4.1.0]heptane and bicyclo[5.1.0]octanes. This reaction involves a reverse regioselectivity in the cyclopropene opening than with gold chlorides. With gem-disubstituted cyclopropenes, a novel cycloisomerization based on ring opening-nucleophilic attac...

Long chain multiantenna N‐glycans are extremely complex molecules from the structural perspective. Their inherent flexibility and the presence of repetitions of monosaccharide units in similar chemical environments hamper their full characterization by X‐ray diffraction or standard NMR methodologies. Therefore, the exploration of their interaction...

Long chain multiantenna N‐glycans are extremely complex molecules from the structural perspective. Their inherent flexibility and the presence of repetitions of monosaccharide units in similar chemical environments hamper their full characterization by X‐ray diffraction or standard NMR methodologies. Therefore, the exploration of their interaction...

Cobalt-catalyzed alkyne cyclotrimerization and crossed [2 + 2 + 2] cycloadditions are developed in a plug flow reactor. The protocol generally uses 5 mol % of Co2(CO)8 and is scalable at least at multigram scale. Efficient and scalable use of Co2(CO)8 for crossed reactions of diynes and alkynes has hardly any precedent.

N‐glycans are ubiquitous in nature and functionalize glycoproteins. Protein glycosylation is required for proper biological and biophysical function and often, alterations in glycosylation are related to diseases.[1] Complex glycosylation patterns containing multiantennary N‐glycans are typically found in mature glycoproteins. However, the structur...

The incorporation of plasma triglyceride (TG) fatty acids to white adipose tissue (WAT) depends on lipoprotein lipase (LPL), which is regulated by angiopoietin-like protein-4 (ANGPTL-4), an unfolding molecular chaperone that converts active LPL dimers into inactive monomers. The production of ANGPTL-4 is promoted by fasting and repressed by feeding...

The biological recognition of complex-type N-glycans is part of many key physiological and pathological events. Despite their importance, the structural characterization of these events remains an unsolved task. The inherent flexibility of N-glycans hampers crystallization and the chemical equivalence of individual branches precludes their NMR char...

The biological recognition of complex-type N-glycans is part of many key physiological and pathological events. Despite their importance, the structural characterization of these events remains an unsolved task. The inherent flexibility of N-glycans hampers crystallization and the chemical equivalence of individual branches precludes their NMR char...

Iminosugars are good starting points for the development of different kinds of drugs. Many are polyhydroxylated piperidines that behave as biomimetics of their corresponding pyranoses analogues. In the interaction with carbohydrate processing enzymes, selectivity is a crucial issue and the benefits of introducing a cyclopropane bridge in a piperidi...

A catalytic, scalable intra- and intermolecular Pauson-Khand reaction protocol using generally 5 mol% of Co2(CO)8 as the catalyst in a plug flow reactor (PFR) is shown.

Stereoselective sulfonium ylide cyclopropanation is a useful transformation due to the presence of this moiety in numerous bioactive compounds. The procedures described to date involve long reaction times and variable stereoselectivity outcomes. We show here that performing these reactions under MW mediation gives good yields and selectivity after...

Protein dynamics related to function can be nowadays structurally well characterized (i. e. instances obtained by high resolution structures) but they are still ill-defined energetically and the energy landscapes are only accessible computationally. This is the case for glucose galactose binding protein (GGBP), where the crystal structures of the a...

Participation of alkenes and allenes in [2+2+2] cycloaddition reactions has attracted much attention recently. This version of the well-established alkyne cyclotrimerization renders interesting products, such as cyclohexadienes and other polycycles, through cascade processes. Many mechanistic variations are observed when using certain metal complex...

Attachment of human noroviruses to histo blood group antigens is thought to be essential for infection of host cells. Molecular details of the attachment process can be studied in vitro using a variety of NMR experiments. The use of protein NMR based experiments requires assignments of backbone NMR signals. Using uniformly 2H,15N-labeled protruding...

Metathesis is one of the most efficient methodologies for the synthesis of large heterocycles. The wide variety of densely functionalized natural structures containing macrocycles and the interest of other nonnatural macrocycles as potential drugs or useful structures for supramolecular chemistry has triggered the synthetic efforts en route to thes...

CXCL12-CXCR4 signaling controls multiple physiological processes and its dysregulation is associated with cancers and inflammatory diseases. To discover as-yet-unknown endogenous ligands of CXCR4, we screened a blood-derived peptide library for inhibitors of CXCR4-tropic HIV-1 strains. This approach identified a 16 amino acid fragment of serum albu...

Ruthenium carbene catalysts are able to catalyze cross [2 + 2 + 2] cyclotrimerizations of 1,6-diynes with cyclic and acyclic double bonds. A plausible mechanistic competition is described in which electron-deficient alkenes follow similar pathways as those of other ruthenium catalysts previously utilized and produce mixtures of trienes and cyclohex...

The increasing interest in the functional versatility of glycan epitopes in cellular glycoconjugates calls for developing sensitive methods to define carbohydrate conformation in solution and to characterize protein-carbohydrate interactions. Measurements of pseudo-contact shifts in the presence of a paramagnetic cation can provide such information...

Hydroxysulfides acted as catalysts to promote the Morita–Baylis–Hillman alkylation reaction of cyclohexenones and dihydropyridinones. The procedure worked efficiently with a variety of halides as electrophiles. Side reactions were in competition with the MBH alkylation, but fine-tuning the reaction conditions minimized their occurence.

The metal-catalyzed [2+2+2] cycloaddition allows the synthesis of carbo- and heterocycles, involving the formation of several C-C bonds in a single step. This elegant, atom-economical and group tolerant process is catalyzed by complexes of more than 17 metals. This chapter covers the most relevant advances in this field after the publication of the...

Controlling NMR shifts by lanthanides tagged to a "symmetrical" N-glycan reveals individual resonances for the residues of the otherwise identical A and B arms. This method provides a global perspective of conformational features and interactions in solution.

Ruthenium carbene catalysts are able to catalyze crossed [2+2+2] cyclotrimerizations of alpha,omega-diynes with isocyanates, isothiocyanates and carbon disulfide. Both aliphatic and aromatic isocyanates can be used to produce fused 2-pyridones, although aliphatic isocyanates were more reactive. Aromatic isocyanates, give better results when bearing...

Unsaturated epsilon-lactams undergo a novel process involving a skeletal reorganization to give fused pyrrolidine-lactones by reaction with aromatic alpha-bromo ketones in the presence of 1,4-diazabicyclo[2.2.2]octane and a base. The process involves the formation of an ammonium salt and subsequently a nitrogen ylide, which initiates the rearrangem...

Hoveyda-Grubbs' catalyst is able to catalyze crossed [2 + 2 + 2] cyclotrimerizations of diynes with nitriles. Pyridines are obtained with excellent yields when using activated nitriles and low to moderate yields with nonactivated nitriles which are unreactive under previously described ruthenium catalyzed reaction conditions. Both terminal and inte...

2-Allyl-1-vinyl-β-carbolines and dihydropyrrolo-β-carbolines react with activated internal alkynes through novel rearrangement reactions leading to complex polycyclic structures. Favored reaction pathways depend on reaction conditions and on the presence of gold catalysts. In particular, upon reaction with 2 equiv. of the alkyne, new hexacyclic str...

Cycloisomerization is a totally atom economic procedure which converts dienes and enynes into cyclic molecules. Modification of Grubbs' 2nd generation catalysts by reaction with dimethylformamide provides a new species able to catalyse this transformation. Selection of suitable conditions allowed high yields and selectivity. Studies performed in or...

In an experimental permanent stroke model, we report here the contribution of ONO-1714 to brain damage prevention. Daily drug administration, twenty-one days prior to and two days after an experimental infarct, was performed by using mini-osmotic pumps (ALZET). Infarct volumes were assessed by image analysis of sequential coronal brain 1 mm(3) sect...

The conformational analysis of a series of tri- and tetrahydroxyazepanes 1–6 designed as noeuromycin mimics has been carried out using 1H NMR spectroscopy assisted by molecular mechanics, molecular dynamics and Monte Carlo calculations. A marked flexibility for these compounds has been found. Superimposition of the branched azepanes with known glyc...

Adrenomedullin (AM) is a regulatory peptide which plays many physiological roles including vasodilatation, bronchodilatation, hormone secretion regulation, growth, apoptosis, angiogenesis, and antimicrobial activities, among others. These regulatory activities make AM a relevant player in the pathophysiology of important diseases such as cardiovasc...

β-Carbolines are present in a wide variety of indole alkaloids that display important biological activities. Here we review the most recent aspects of the chemistry of β-carbolines with a focus on functionalization of the β-carboline system and transformations into other interesting compounds. Aromatizations, reductions and alkylations of the heter...

The first synthesis of a carbohydrate molecule covalently bound to a rigid lanthanide binding tag is reported. This derivative has been designed as a new tool to provide long-range restraints for structural elucidation and molecular recognition studies of carbohydrates, thus extending the methodology already developed for proteins.

Keywords: Natural products / Nitrogen heterocycles / Alkaloids / Rearrangement / β-Carbolines β-Carbolines are present in a wide variety of indole alkaloids that display important biological activities. Here we review the most recent aspects of the chemistry of β-carbolines with a focus on functionalization of the β-carboline system and transformat...

The [2+2+2] cycloaddition is an elegant, atom-efficient and group tolerant process for the synthesis of carbo- and heterocycles, mostly aromatic, involving the formation of several C-C bonds in a single step. Cyclotrimerisation is catalyzed by a variety of organometallic complexes, including more than 15 different metals. The aim of this tutorial r...

A new protocol uses the Hoveyda—Grubbs catalyst for the reaction of diynes with alkynes.

For Abstract see ChemInform Abstract in Full Text.

To infect host cells, most enveloped viruses must insert a hydrophobic fusion peptide into the host cell membrane. Thus, fusion peptides may be valuable targets for developing drugs that block virus entry. We have shown previously that a natural 20-residue fragment of α(1)-antitrypsin, designated VIRus-Inhibitory Peptide (VIRIP), that binds to the...

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

The synthesis and evaluation of new ligands for the H3 receptor of histamine is described. These new compounds are diimidazopyridine derivatives readily prepared by a condensation reaction of spinacine and isocyanates.

Six-membered α,β-unsaturated lactones and lactams are found to be suitable as substrates.

Unsaturated δ-lactams are cyclopropanated with the aid of diazo compound decomposition catalysed by metal complexes. A study of the reaction conditions, stereochemical outcome and group protection is reported. The resulting bicyclic products are related to bioactive compounds. Transformation into thiolactams facilitates the separation of the differ...

Second-generation Grubbs' catalyst and Hoveyda-Grubbs' catalyst are able to catalyze both crossed [2+2+2] cyclotrimerization of diynes with alkynes and di- or trimerizations of diynes. Selection of the reaction conditions allows us to favor one particular process. The process is selective when applied to unsymmetric diynes.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

] Keywords: Nitrogen heterocycles / Cyclopropanation / Polycycles / Lactams / Diastereoselectivity Unsaturated δ-lactams are cyclopropanated with the aid of diazo compound decomposition catalysed by metal com-plexes. A study of the reaction conditions, stereochemical outcome and group protection is reported. The resulting bi-cyclic products are rel...

IntroductionOrganization of the ChapterMacrocyclic PolyketidesTerpenoidsMacrocycles of Amino Acid OriginMacrocyclic GlycolipidsConclusions and OutlookReferences

Cyclopropanation of α,β-unsaturated δ-lactams and δ-lactones mediated by nitrogen ylides is described. The process tolerates different alkyl halides and gives efficiently bicyclo[4.1.0]heptanes in a totally stereoselective manner. On the other hand, ε-lactams under our experimental conditions suffer a novel process involving a skeletal reorganizati...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A new Morita-Baylis-Hillman reaction methodology in which alkyl halides and epoxides act as electrophiles in their reaction with lactones and lactams is shown. Catalysis is efficiently performed by hydroxy sulfides under basic conditions. The procedure works efficiently with many alkyl halides but fails with aldehydes with which a conventional acid...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

3,4-Enynoindoles undergo metathesis reactions leading to structures related to alkaloids. The formation of an unexpected product is reported and discussed.

The gold-catalysed reactions of alleneamides give different products depending on the substrate and the reaction conditions. In particular, N-(2-alkynylphenyl)-N-allenyltosylamides give benzazepines when using gold(III) catalysts in the presence of nucleophiles. This sequential process may follow two different reaction pathways, and these are discu...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Functionalization of β-carbolines is a challenge as numerous natural alkaloids with different biological activities present this heterocycle. The RCM is used herein with allyl-, vinyl-, ethynyl-, and propargyl-β-carbolines to generate additionally fused hetero- and carbocycles, and it is combined with other cyclization processes to achieve great mo...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of new bicyclic structures containing cyclopropanes, related to selective iNOS inhibitor ONO-1714, is described. We have evaluated the effect of the compounds obtained on the production of nitric oxide in lipopolysaccharide and interferon-gamma stimulated mouse peritoneal macrophages and on in vitro iNOS activity assays.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Vinylpyrrolo-[2,1-a]-β-carbolines 1 give different products upon reaction with dienophiles. With dimethyl acetylenedicarboxylate (DMAD), a novel domino process takes place, involving Michael attack and rearrangement, affording complex polycycles like 3, 4, and 5. Diels–Alder cycloadditions are favored in the presence of Lewis acids and are the only...

The combination of ring-closing metathesis (RCM) followed by an intramolecular Pauson–Khand reaction gives direct entry to tricyclic compounds. The RCM was carried out on a hexacarbonylcobalt-complexed alkyne, this complex acting as a protecting group against enyne metathesis. The procedure was studied for dienynes containing heteroatoms and allows...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Construction of quaternary carbons is a challenge in PK chemistry, with few precedents in the literature. Starting from suitable functionalized enynes including an aromatic ring that templates the reaction, polycyclic ketones are obtained with a quaternary carbon. Special reaction conditions are necessary including the use of molecular sieves and c...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Pauson–Khand reactions of functionalized allenes with different alkynes give cyclopentenones with generally high regio- and stereoselectivities. The allenes react through their external double bonds, giving cyclopentenones with exocyclic double bond at their β positions and predominantly with E stereochemistry. Some intramolecular reactions with al...

A new triple tandem process has been discovered in which simple acyclic substrates can be transformed into bicyclic compounds via RCM-double bond isomerization-cyclopropanation. This process is catalyzed by second generation Grubb's catalyst without the requirement of other reactives or additives. In addition, a one-pot RCM-isomerization reaction f...

New experimental conditions have been developed for an efficient catalytic Pauson–Khand reaction. These are based on the use of a mixture of molecular sieves and tert-butanol as inducers of the process. This mixture, with the appearance of a paste, is able to adsorb CO, thus improving the conversion and making it possible to effect the reactions in...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The complexation of an arene to a chromium tricarbonyl unit changes its chemical behavior, giving rise to unprecedented transformations. The electron-withdrawing effect of the unit allows efficient nucleophilic attack (S(N)Ar and dearomatization reactions), stabilizes negative charges in benzylic positions and activates C(Ar)-halogen bonds for cros...

CgNa (Condylactis gigantea neurotoxin) is a 47-amino-acid- residue toxin from the giant Caribbean sea anemone Condylactis gigantea. The structure of CgNa, which was solved by 1H-NMR spectroscopy, is somewhat atypical and displays significant homology with both type I and II anemone toxins. CgNa also displays a considerable number of exceptions to t...

A combination of experimental J/NOE NMR data with molecular mechanics and dynamics calculations has been used to examine the conformational behaviour and assign the configuration of synthetically prepared epimeric 3-carboxymethyl-O-Gal-(1-->1)-alpha-Man-fluoro-C-glycosides. It is shown that the population distributions around the glycosidic linkage...

The construction of macrocycles by ring-closing metathesis (RCM) is often used as the key step in the synthesis of natural products containing large rings. This reaction is attractive because of its high functional group compatibility and the possibility for further transformations. The finding of suitable reaction conditions is critical for the su...

Der Aufbau von Makrocyclen durch Ringschlussmetathese (RCM) ist oft eine Schlüsselstufe bei der Synthese von Naturstoffen mit großen Ringen. Diese Reaktion bietet sich an wegen ihrer hohen Toleranz für funktionelle Gruppen sowie der Möglichkeit zu nachfolgenden Umwandlungen. Dabei ist die Wahl geeigneter Reaktionsbedingungen für den Erfolg der Synt...

[reactions: see text] We show the use of arene-chromium tricarbonyl complexes in intra- and intermolecular Pauson-Khand reactions. Both styrene and ethynylbenzene complexes react with alkynes and olefins. The synthesis of enynes connected through chromium-complexed aromatic rings is developed. The intramolecular Pauson-Khand reaction occurs in a to...

The synthesis of a series of C3'-cis-substituted carboxycyclopropyl glycines bearing a wide variety of functional groups is described, and the structure-activity relationship for this series as agonists of group II metabotropic glutamate receptors is reported.

This chapter contains sections titled: Molecular sieves as promoters for the catalytic Pauson-Khand reaction Palladium(II)-catalysed cyclization of alkynes with aldehydes, ketones or nitriles initiated by acetoxypalladation of alkynes Rhodium(I)-catalysed intramolecular alder-ene reaction and syntheses of functionalised α-methylene-γ-butyrolactones...

New indolic enynes and dienynes, based on the β-carboline system, give metathesis products with ruthenium catalysts. The synthesis of the starting materials is readily achieved from tryptamine. The tuning up of the conditions for the metathesis is discussed. Cascade metathesis gives an oxidized pentacyclic product.