Synthesis of a molecularly defined single-active site heterogeneous catalyst for selective oxidation of N-heterocycles.

Generally, a homogeneous catalyst exhibits good activity and defined active sites but it is difficult to recycle. Meanwhile, a heterogeneous catalyst can easily be reused but its active site is difficult to reveal. It is interesting to bridge the gap between homogeneous and heterogeneous catalysis via controllable construction of a heterogeneous catalyst containing defined active sites.

Carbonylative coupling of N-chloroamines with alcohols: synthesis of esterification reagents.

Herein we report a new method for the carbonylative synthesis of carbamates. Starting from N-chloroamines and alcohols, with copper or Pd/C as the catalyst, the corresponding carbamates were produced in moderate to good yields. No additional oxidant or base is needed in this system.

Palladium-Catalyzed Selective Generation of CO from Formic Acid for Carbonylation of Alkenes.

A general and selective palladium-catalyzed alkoxycarbonylation of all kinds of alkenes with formic acid (HCOOH, FA) is described. Terminal, di-, tri-, and tetra-substituted including functionalized olefins are converted into linear esters with high yields and regioselectivity. Key-to-success is the use of specific palladium catalysts containing ligands with built-in base, e.

A chemometric study in the area of feasible solution of an acid-base titration of -methyl-6-oxyquinolone.

Multivariate curve resolution methods aim at recovering the underlying chemical components from spectroscopic data on chemical reaction systems. In most cases the spectra and concentration profiles of the pure components cannot be uniquely determined from the given spectral data. Instead continua of possible factors exist.

Multi-objective optimization for an automated and simultaneous phase and baseline correction of NMR spectral data.

Spectral data preprocessing is an integral and sometimes inevitable part of chemometric analyses. For Nuclear Magnetic Resonance (NMR) spectra a possible first preprocessing step is a phase correction which is applied to the Fourier transformed free induction decay (FID) signal. This preprocessing step can be followed by a separate baseline correction step.

A copper-catalyzed carbonylative four-component reaction of ethene and aliphatic olefins.

To have a balance between reactivity and selectivity has been a long-standing challenge in multicomponent reactions. In this communication, a carbonylative four-component reaction has been developed. With copper as the catalyst, using ethene including other aliphatic alkenes, alcohols and acetonitrile as the substrates under CO pressure, various desired products were produced in moderate to good yields.

Toward Green Acylation of (Hetero)arenes: Palladium-Catalyzed Carbonylation of Olefins to Ketones.

Green Friedel-Crafts acylation reactions belong to the most desired transformations in organic chemistry. The resulting ketones constitute important intermediates, building blocks, and functional molecules in organic synthesis as well as for the chemical industry. Over the past 60 years, advances in this topic have focused on how to make this reaction more economically and environmentally friendly by using green acylating conditions, such as stoichiometric acylations and catalytic homogeneous and heterogeneous acylations.

Copolymerization of CO and epoxides mediated by zinc organyls.

Herein we report the copolymerization of CHO with CO in the presence of various zinc compounds RZn (R = Et, Bu, Pr, Cy and Ph). Several zinc organyls proved to be efficient catalysts for this reaction in the absence of water and co-catalyst. Notably, readily available BuZn reached a TON up to 269 and an initial TOF up to 91 h.

Acridinedione as selective flouride ion chemosensor: a detailed spectroscopic and quantum mechanical investigation.

The use of small molecules as chemosensors for ion detection is rapidly gaining popularity by virtue of the advantages it offers over traditional ion sensing methods. Herein we have synthesized a series of acridine(1,8)diones (7a-7l) and explored them for their potential to act as chemosensors for the detection of various anions such as fluoride (F), acetate (OAc), bromide (Br), iodide (I), bisulfate (HSO ), chlorate (ClO ), perchlorate (ClO ), cyanide (CN), and thiocyanate (SCN). Acridinediones were found to be highly selective chemosensors for fluoride ions only.

Synthesis of Unsymmetrical Aza-Ullazines by Intramolecular Alkynyl-Carbonyl Metathesis.

A variety of aza-ullazines were synthesized in one step from readily accessible 3,5-dialkynyl-4-pyrrolopyridine via acylation followed by intramolecular alkynyl carbonyl metathesis. The reaction conditions were optimized, and the preparative scope was studied. The optoelectronic properties of selected aza-ullazines were studied by UV/vis and fluorescence spectroscopy.

Rhodium-catalyzed carbonylative synthesis of silyl-substituted indenones.

A novel and efficient rhodium-catalyzed procedure for the preparation of silyl-substituted indenones has been developed. Using silanes and internal alkynes as the substrates, in the presence of CO, good to excellent yields of the desired indenones were isolated. A wide range of functional groups, encompassing esters, amines, nitriles and halides, is compatible in this system.

Cobalt-catalysed reductive C-H alkylation of indoles using carboxylic acids and molecular hydrogen.

The direct CH-alkylation of indoles using carboxylic acids is presented for the first time. The catalytic system based on the combination of Co(acac) and 1,1,1-tris(diphenylphosphinomethyl)-ethane (Triphos, ), in the presence of Al(OTf) as co-catalyst, is able to perform the reductive alkylation of 2-methyl-1-indole with a wide range of carboxylic acids. The utility of the protocol was further demonstrated through the C3 alkylation of several substituted indole derivatives using acetic, phenylacetic or diphenylacetic acids.

Non-noble metal-catalysed carbonylative transformations.

Transition metal catalysts are formidable tools towards greener chemistry, allowing for low-waste, energy-efficient, and selective reactions. And transition metal-catalysed carbonylation procedures are powerful methodologies for producing carbonyl-containing compounds. The existing reviews/chapters/books are mainly focused on noble metal (Ru, Rh, Ir, Pd, Pt) catalysed carbonylation reactions.

Synthesis and coordination chemistry of the PPN ligand 2-[bis(diisopropylphosphanyl)methyl]-6-methylpyridine.

The synthesis and crystal structure of the multidentate PPN ligand 2-[bis(diisopropylphosphanyl)methyl]-6-methylpyridine (L), CHNP, are described. In the isostructural tetrahedral Fe and Co complexes of type LMCl (M = Fe, Co), namely {2-[bis(diisopropylphosphanyl)methyl]-6-methylpyridine-κP,N}dichloridoiron(II), [FeCl(CHNP)], and {2-[bis(diisopropylphosphanyl)methyl]-6-methylpyridine-κP,N}dichloridocobalt(II), [CoCl(CHNP)], the ligand adopts a bidentate P,N-coordination, whereas in the case of the octahedral Mn complex {2-[bis(diisopropylphosphanyl)methyl]-6-methylpyridine-κP,P'}bromidotricarbonylmanganese(I), [MnBr(CHNP)(CO)], the ligand coordinates via both P atoms to the metal centre.

Highly Efficient and Robust Enantioselective Liquid-Liquid Extraction of 1,2-Amino Alcohols utilizing VAPOL- and VANOL-based Phosphoric Acid Hosts.

The large-scale production of enantiopure compounds in a cost-effective and environmentally friendly manner remains one of the major challenges of modern-day chemistry. The resolution of racemates through enantioselective liquid-liquid extraction was developed as a suitable solution but has remained largely underused, owing to a lack of highly efficient and robust chiral hosts to mediate the process. This paucity of hosts can in part be attributed to a poor understanding of the underlying principles behind these processes hindering the design of more efficient selectors.

Silver and Palladium Cocatalyzed Carbonylative Activation of Benzotriazoles to Benzoxazinones under Neutral Conditions.

A novel and efficient method for the carbonylative activation of benzotriazoles to benzoxazinones has been developed. By using a silver and palladium bimetallic catalyst system, a broad range of benzotriazoles were transformed into the corresponding benzoxazinones in moderate to good yields with excellent functional group tolerance. Notably, this procedure proceeds under neutral conditions.

Versatile palladium-catalyzed double carbonylation of aryl bromides.

A versatile palladium-catalyzed double carbonylation of aryl bromides has been developed. Using Pd(OAc)/BuPAd as the catalyst system and DBU as the base, under relatively low CO pressure, various α-ketoamides were produced in good yields. In order to get insight into the reaction pathway, real time NMR studies were performed as well and a correlated reaction mechanism is been given.

Highly efficient enantioselective liquid-liquid extraction of 1,2-amino-alcohols using SPINOL based phosphoric acid hosts.

Access to enantiopure compounds on large scale in an environmentally friendly and cost-efficient manner remains one of the greatest challenges in chemistry. Resolution of racemates using enantioselective liquid-liquid extraction has great potential to meet that challenge. However, a relatively feeble understanding of the chemical principles and physical properties behind this technique has hampered the development of hosts possessing sufficient resolving power for their application to large scale processes.

Selective cobalt nanoparticles for catalytic transfer hydrogenation of N-heteroarenes.

Nitrogen modified cobalt catalysts supported on carbon were prepared by pyrolysis of the mixture generated from cobalt(ii) acetate in aqueous solution of melamine or waste melamine resins, which are widely used as industrial polymers. The obtained nanostructured materials catalyze the transfer hydrogenation of N-heteroarenes with formic acid in the absence of base. The optimal Co/Melamine-2@C-700 catalyst exhibits high activity and selectivity for the dehydrogenation of formic acid into molecular hydrogen and carbon dioxide and allows for the reduction of diverse N-heteroarenes including substrates featuring sensitive functional groups.

Unprecedented selective homogeneous cobalt-catalysed reductive alkoxylation of cyclic imides under mild conditions.

The first general and efficient non-noble metal-catalysed reductive C2-alkoxylation of cyclic imides (phthalimides and succinimides) is presented. Crucial for the success is the use of [Co(BF)·6HO/triphos ()] combination and no external additives are required. Using the optimal cobalt-system, the hydrogenation of the aromatic ring of the parent phthalimide is avoided and only one of the carbonyl groups is selectively functionalized.

MOF-derived cobalt nanoparticles catalyze a general synthesis of amines.

The development of base metal catalysts for the synthesis of pharmaceutically relevant compounds remains an important goal of chemical research. Here, we report that cobalt nanoparticles encapsulated by a graphitic shell are broadly effective reductive amination catalysts. Their convenient and practical preparation entailed template assembly of cobalt-diamine-dicarboxylic acid metal organic frameworks on carbon and subsequent pyrolysis under inert atmosphere.

Insight into the Activation of In Situ Generated Chiral Rh Catalysts and Their Application in Cyclotrimerizations.

We report a detailed study concerning the efficient generation of highly active chiral rhodium complexes of the general structure [Rh(diphosphine)(solvent) ] as well as their exemplary successful utilization as catalysts for cyclotrimerizations. Such solvent complexes could likewise be prepared from novel ammonia complexes of the type [Rh(diphosphine)(NH ) ] . A valuable, feasible approach to generate novel chiral Rh complexes was found by in situ generation from Wilkinson's catalyst [RhCl(PPh ) ] with chiral P,N ligands.

Titanocene Silylpropyne Complexes: Promising Intermediates en route to a Four-Membered 1-Metallacyclobuta-2,3-diene?

Coordination of the alkyl-substituted alkynes Me SiC CH R (1: R=SiMe ; 2: R=N(SiMe ) ) to titanocene centres [Cp' Ti] (Cp'=Cp, Cp*) yields stable alkyne complexes of the type Cp' Ti(η -Me SiC CH R) (3: Cp'=Cp, R=SiMe ; 5: Cp'=Cp, R=N(SiMe ) ; 6: Cp'=Cp*, R=SiMe ) that are not prone to alkyne/allene isomerisation. When reacting alkyne 2 with Cp TiCl and Mg formation of the complex Cp* Ti(III)(η -Me SiC CH ) (7) which displays a propargylic unit coordinated to the Ti centre takes place. All complexes were fully characterised, the molecular structures for 5, 6, and 7 are discussed.

Arsenic-Mediated C-C Coupling of Cyanides Leading to Cyanido Arsazolide [AsC N ].

The chemistry of arsenic cyanides has been investigated and is found to be completely different to the chemistry of the heavier analogs antimony and bismuth as well as phosphorus. The reaction of As(CN) with cyanide salts resulted in the formation of an unknown cyanido arsazolide heterocycle, which represents a structure isomer of the desired [As(CN) ] . The structure, bonding, and formation of this unusual heterocycle is discussed featuring an arsenic mediated C-C coupling of cyanides.

3-Acylindoles Synthesis: Ruthenium-Catalyzed Carbonylative Coupling of Indoles and Aryl Iodides.

A novel and convenient procedure for the synthesis of 3-acylindoles from simple indoles and aryl iodides has been established. Through ruthenium-catalyzed carbonylative C-H functionalization of indoles, with Mo(CO) as the solid CO source, the desired indol-3-yl aryl ketones were isolated in moderate to good yields. Not only N-alkylindoles but also N-H indoles can be applied here.