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Herein an extremely versatile, well-defined, low-valent cobalt catalyst [Co(PMe3)4] capable of intermolecular and intramolecular imine-directed C2-alkylation and alkenylation of indoles is reported. The reaction proceeds in the absence of reducing agents or additives, affording a range of substituted indoles and dihydropyrroloindoles in high yields and regioselectivities. With the aid of deuterium labeling studies and DFT (Density Functional Theory) calculations, a mechanism is proposed that is based on a Ligand-to-Ligand Hydrogen Transfer pathway.

Diamine-monoboranes and one amine-borane alcohol precursor are utilized for cyclization reactions affording the corresponding NB(H)N- and NB(H)O-containing cyclic diaminoboranes and oxazaborolidine, resp.

Samples of SrFe1-xTixO3-δ (x = 0-0.3) are prepared by sol-gel reaction of stoichiometric amounts of Sr(NO3)2, Fe(NO3)3,Ti(O-iPr)3, and citric acid in a 2:1 EtOH/H2O solution followed by firing of the obtained gel and sintering of pressed pellets (1300 °C, 17 h).

CaTeO3(H2O) is prepared by microwave-assisted hydrothermal reaction of Ca(NO3)2, TeO2, NaOH, and H2O (microwave furnace, autoclave, 185 °C, 1 h).

A facile C–H activation and functionalization of aromatic imines is presented using low-valent cobalt catalysts. Using Co(PMe3)4 as catalyst we have developed an efficient and simple protocol for the C–H/hydroarylation of alkynes with an anti selectivity. Deuterium-labeling experiments, DFT calculations coupled with the use of a well-defined catalyst have for the first time shed light on the elusive black box of cobalt catalyzed C–H functionalization.

The title compound, N2H4(BH3)2, is prepared from a mixture of freshly ground [N2H5][HSO4] and NaBH4 in THF (Ar-filled glovebox, round-bottom flask, 40 °C, 42—90 h, 87% yield).

A new and efficient synthesis of highly sensitive benzosilacyclobutenes has been developed. For the first time, these compounds can be synthesized in very high yields by a mild, unprecedented intramolecular niobium-catalyzed [2 + 2 + 2] cycloaddition of easily accessible tetrasubstituted sila-triynes. An easy access to highly functionalized benzosilacyclobutenes enlarging the number of potential applications in organic and material chemistry is described.

Polysaccharides are a natural and renewable feed stock for synthesizing high performance macromolecular materials. However, their structure does not allow reaching all properties required for specific applications and chemical modifications are necessary to reach such objectives. Despite the use of natural polymers, the chemistry and processes employed are not environment-friendly due to the nature of chemicals, solvents or because the conventional chemical process are energy-consuming. On the other hand, microwave assisted processes were developed in organic chemistry since the 1980s and more recently for polymer chemistry (polymer formation and modification). Within the chemistry of natural polymers, the use of microwave irradiation has been exploited in the past two decades to alleviate limitations in the synthesis of graft modified polysaccharide materials. Microwave heating is described as more homogeneous, selective and efficient as compared to conventional heating resulting in faster reactions with fewer or no side products as example. Different results reported within the recent literature will be discussed considering the role of microwave irradiation and its consequence on the reaction parameters and properties of final materials. Grafting of polysaccharides, specific modification of polysaccharides or fibers particularly for preparing smart textiles or medical products as well as reactions of polysaccharides to valuable bio-platform molecule will be discussed. © 2014 IUPAC & De Gruyter.

The use of the 2-(4-methylphenylsulfonyl)ethenyl (tosvinyl, Tsv) group for the protection of the NH group of a series of imides, azinones (including AZT), inosines, and cyclic sulfonamides has been examined. The Tsv-protected derivatives are obtained in excellent yields by conjugate addition to tosylacetylene (ethynyl p-tolyl sulfone). The stereochemistry of the double bond can be controlled at will: with only 1 mol % of Et3N or with catalytic amounts of NaH, the Z stereoisomers are generated almost exclusively, while the E isomers are obtained using a stoichiometric amount of DMAP. Analogous phenylsulfonylvinyl-protected groups (with the besvinyl or Bsv group instead of Tsv) are obtained stereospecifically by reaction with (Z)- or (E)-bis(phenylsulfonyl)ethene. For lactams and oxazolidinones, this last method is much better. The Tsv and Bsv groups are stable in the presence of non-nucleophilic bases and to acids. They can be removed highly effectively via a conjugate addition-elimination mechanism using pyrrolidine or sodium dodecanethiolate as nucleophiles.

Three regiodivergent Baeyer–Villiger mono-oxygenases (enantioselectively) oxidized a series of cyclic α,β-unsaturated ketones into (chiral) either enol-lactones or ene-lactones. An easy-to-use and efficient biocatalytic process based on a host-microorganism deprived of unwanted activities (knock-out mutant) was developed to enable the exclusive synthesis of unsaturated lactones.

The dimerization of arylacetylenes in the presence of the hydrido-cobalt complex proceeds with high regio- and stereoselectivity to produce (E)-1,4-enynes in excellent yield.

Review: involving three types of frustrated compounds: pyrochlore-type magnets, multifrroics, and chiral magnets; 99 refs.

Double bond isomerization of cycloalkenes is achieved via radical addition of p-chlorothiophenol, oxidation to sulfoxides, and thermal syn-elimination.

Two generally applicable systems have been developed for the cross-coupling of P(O)H compounds with Csp2X and related partners. Palladium catalysis using a ligand/additive combination, typically either xantphos/ethylene glycol or 1,1′-bis(diphenylphosphino)ferrocene/1,2-dimethoxyethane, with diisopropylethylamine as the base, proved to be generally useful for the synthesis of numerous PC containing compounds. Routinely, 2 mol% of catalyst are employed (less than half the amount typically employed in most other literature reports). In most cases, excellent results are obtained with a variety of electrophiles (RX, where R=alkenyl, allyl, alkynyl, etc.). The full account of our studies is disclosed, including tandem hydrophosphinylation/coupling and coupling/coupling for doubly catalytic phosphorus-carbon bond formation. The methodology compares favorably with any existing literature report. The use of an additive appears to be a generally useful strategy to control the reactivity of phosphinylidene compounds.

Go cyclic! The use of [Co(H)(PMe3)4] as a cobalt catalyst allows the previously unattainable catalytic version of the cobalt-mediated cycloaddition of enediynes without the requirement of thermal or light activation (see scheme). The importance of a chelating group on the substrate that can selectively direct the reaction pathway toward the classical polycyclic 1,3-cyclohexadienes or a new family of bicyclic trienes is also demonstrated.

Using copper-catalysed Huisgen 1,3-dipolar cycloaddition, we describe the synthesis of new A-π-D compounds containing a pyrimidine moiety as π-acceptor (A) and various para-substituted benzene rings as donors (D). Structure–photophysical properties relationships revealed the triazole ring to be a better π-conjugated linker than the triple bond.

In2Ga2Fe2O9 and Sc2Ga2Fe2O9 are prepared by solid state reaction of stoichiometric mixtures of M2O3 (M: In, Sc), Ga2O3, and Fe2O3 (air, 11375—1400 °C, 24—30 h).

The method avoids the use of Me-PCl2 and neither a metal catalyst nor a protecting group strategy are required.

The degenerate transfer of xanthates allows generally difficult radical transformations, such as intermolecular additions to unactivated alkenes and cyclisations onto aromatic and heteroaromatic rings, to be accomplished under very practical experimental conditions. This translates into numerous approaches for the construction or modification of heteroaromatic structures. The present report aims to provide a brief overview of the various synthetic possibilities, with particular emphasis on medicinally interesting families of compounds.

We thank the Australian Research Council and the Institute of Advanced Studies for generous financial support.

A convenient two-step sequence allows the synthesis of the title compounds via radical addition of xanthates to substrate (I) followed by radical cyclization onto the pyridine ring.

Several 2,5-diaryloxazole derivatives of type (III) (14 examples) and bisoxazoles of type (VI) (7 examples) are prepared by the title method.

The first metal-catalyzed hydrophosphinylation of unsaturated hydrocarbons with H-phosphinic acids is described. A strategy to activate the PH bond through control of the tautomeric equilibrium using ethylene glycol is described. The reactions also avoid chromatographic purification.

Trifluoroazaindoline derivatives are prepared using the first synthetically useful radical ipso-substitution of a fluorine atom. The initial procedure has been improved to allow the gram scale synthesis of these building blocks, which can be regioselectively substituted by nucleophiles under mild conditions to rapidly access a library of new molecules. Oxidation to the corresponding fluoroazaindole core has also been accomplished.

The palladium-catalyzed cross-coupling reaction between H-phosphinate esters and chloroarenes or chloroheteroarenes is described. This reaction is the first general metal-catalyzed phosphorus–carbon bond-forming reaction between a phosphorus nucleophile and chloroarenes.

Co2V2O7 is synthesized by solid state reaction of CoCO3 and V2O5 (600 °C, 7 d) and characterized by XRD and conductivity measurements in oxidizing as well as reducing environments.

Radicals generated on the side chain of 2- or 4-N-alkylamino-4,6- or 2,6-dichloropyrimidines can cyclize via the nitrogen or the carbon atom of the pyrimidine ring depending on its position and on whether an acetyl or a Boc group is present.

Rare examples of a synthetically useful radical ipso substitution of a carbon−fluorine bond are reported. Highly functionalized fluoroazaindoline structures have thus been prepared with use of chea...

Xanthates derived from unprotected 2-hydroxyacetophenones undergo intermolecular addition to unactivated alkenes such as (II) and subsequent intramolecular ring closure to give hydroxytetralones (IV), (VI) and (VIII).

A new efficient synthesis of L-fucose (and 6-alkyl analogs) in only six steps from D-mannose is described. This transfromation is based on addition of an organometallic reagent to the bis-acetonide of D-mannose followed by selective glycol cleavage with sodium periodate. Efficient separation of diastereomeric dibenzoates and formation of 2,5-di-benzyl (or benzoyl)-L-fucofuranose derivatives are also noteworthy.

Chiral bidentate aminophosphinephosphinites (AMPP) ligands bearing different substituents at the aminophosphine and the phosphinite moieties are prepared in a one pot synthesis from aminoalcohols. Their use in asymmetric hydrogenation of activated ketones is described. Upon analysis of these results, it is suggested that the phosphinamido group governs both the activity and the enantioselectivity of this reaction.

Optically active 2-alkysuccinates were obtained as their monoesters by stereopecific substitution of the p-toluenesulfonates or p-nitrobenzenesulfates of α-hydroxy esters with sodium di-tert-butyl malonate, followed by hydrolysis and decarboxylation of the resulting diacids.

The ring opening of epoxycyclohexane by 2-propanol and 2-methyl-2-propanol is performed at room temperature with tin cobalt catalyst with a 100% selectivity into β-alkoxy alcohols. 2-alkoxy-2'-hydroxydicyclohexylether compounds arising from the subsequent attack of 2-alkoxycyclohexanol on epoxycyclohexane are also obtained. The divalent tin complex Sn[Co(CO) 4 ] 2 , obtained either by reductive elimination of Co 2 (CO) 8 from Sn[Co(CO) 4 ] 4 or, more efficiently, by splitting of the new dimer [Sn[Co(CO) 4 ] 2 ] 2 , is proposed as the active catalytic species

The direct synthesis of lactones is performed by double carbonylation of (2-bromoethyl)benzene under carbon monoxide pressure. The reaction is catalyzed by Sn(Co(CO) 4 )) 4 in the presence of a base in hydro-alcoholic medium.

The recently described electrochemical procedure for the preparation of phthalocyanines has been successfully applied for the synthesis of octasubstituted phthalocyanines (dihydrogen PcH 2 and radical lithium PcLi o forms). Yields of isolated materials are in the 50-70% range, i.e. better than those generally obtained using conventionnal chemical procedures. Results agree with the electrochemical properties of the starting disubstituted phthalonitriles and the previously suggested mechanism of the electrosynthesis

Enzyme-catalyzed preparation of β-2-deoxy-D-glucosides and galactosides including disaccharides has been achieved using the corresponding glycals as substrates.

An efficient and short synthesis of vitamin C has been accomplished from L-galactono-1,4-lactone via methyl 3,5:4,6-di-O-ethylidine-L-galactonate.

Enantiomerically pure R or S 1,3-butanediols were prepared in four steps from L or D threonine by nitrous deamination in the presence of bromide ion followed by esterification and reduction.

Practical and simple techniques are described for using nonmodified domestic microwave ovens as safe and convenient laboratory devices to obtain numerous esters. High pressures are avoided by condu...