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A concise strategy for the synthesis of vinylsilanes from an iron-catalyzed regio- and stereoselective hydrosilylation of terminal alkynes has been developed. The catalyst and reagents are commercially available and easy to handle, providing a simple and practical method for iron-catalyzed anti-Markovnikov hydrosilylation with a good functional group tolerance. [ABSTRACT FROM AUTHOR]

The substituent redistribution of hydrosilanes on silicon through C-Si and Si-H bond cleavage and reformation is of great interest and importance, but this transformation is usually difficult to achieve in a selective fashion. By using electron-rich aromatic hydrosilanes, we have achieved for the first time the selective C-Si/Si-H bond homo- and cross-metathesis of a series of hydrosilanes in the presence of a boron catalyst B(C6F5)3. This protocol features simple reaction conditions, high chemoselectivity, wide substrate scope, and high functionality tolerance, offering a new pathway for the synthesis of multisubstituted functional silanes. [ABSTRACT FROM AUTHOR]

For enhancing the partial nitritation-anammox (PN/A) process, the effects of granule fraction on system performance were investigated in this study. Two sequencing batch reactors (SBRs) were inoculated with PN/A biomass with a floc mass fraction of 53%. In SBR1, when the nitrogen removal rate (NRR) was stable, flocculent sludge was gradually discharged from the reactor using a screen, and the granule fraction was therefore increased. However, nitrogen removal was not improved and finally deteriorated due to the loss of nitritation activity. In SBR2, most flocculent sludge was eliminated and granular proportion was maintained at over 90% by controlling a short settling and decanting time. NRR was low initially but gradually improved to 1.23 kg N/(M³⋅d), which was 54% higher than SBR1. Ammonium oxidation activities of flocs and granules were respectively measured. Results suggested that the increase of nitritation activity in the granules was the main reason for the improvement of nitrogen removal in SBR2. [ABSTRACT FROM AUTHOR]

Transition metal catalysis plays a central role in contemporary organic synthesis. Considering the tremendously broad array of transition metal-catalyzed transformations, it is remarkable that the underlying elementary reaction steps are relatively few in number. Here, we describe an alternative to the organometallic transmetallation step that is common in many metal-catalyzed reactions, such as Suzuki-Miyaura coupling. Specifically, we demonstrate that vinyl boronic ester ate complexes, prepared by combining organoboronates and organolithium reagents, engage in palladium-induced metallate rearrangement wherein 1,2-migration of an alkyl or aryl group from boron to the vinyl a-carbon occurs concomitantly with C-Pd s-bond formation. This elementary reaction enables a powerful cross-coupling reaction in which a chiral Pd catalyst merges three simple starting materials--an organolithium, an organoboronic ester, and an organotriflate--into chiral organoboronic esters with high enantioselectivity. [ABSTRACT FROM AUTHOR]

Our calculations found that the O∴O three-electron (3e) bonds (2.16∼2.27 Å) can be formed not only between two neighboring peptide units in a main chain but also between two adjacent peptide units in two different main chains in proteins. This finding may address electron hole migration from one peptide unit to the next in proteins. Evidently, stability of the O∴O 3e bonded species is strongly dependent on the component of the oligopeptides and is reduced owing to the steric hindrance of the side chains when the big chains present in oligopeptides. Besides, formation of the O∴O 3e bonds competes with the formation of the other forms of three-electron bonds depending on the component of the polypeptides. Formation of the O∴S 3e bond is thermodynamically more favorable than that of the O∴O 3e bond for the oligopeptides containing sulfur atom in their side chains. Similarly, formation of the O∴π 3e bond between aromatic ring of the side chain and the neighboring peptide unit is more stable than that of the O∴O 3e bond when the aromatic amino acids present in the oligopeptides. We infer that a series of three-electron bonds may be formed during the electron hole migration along the peptide backbone in proteins and assist electron hole transport as relay stations, supporting the peptide chain as a conduction wire. The ab initio molecular dynamics simulations of the polypeptides also support this conclusion. [ABSTRACT FROM AUTHOR]

The combination of palladium acetate with XPhos shows high efficiency in the Hiyama cross-coupling reactions of aryl mesylates with arylsilanes. The reactions proceed smoothly to generate the corresponding biaryl compounds in good yields. [ABSTRACT FROM AUTHOR]

Pd-catalyzed Suzuki—Miyaura cross-coupling reaction of aryl tosylates with potassium aryl trifluoroborate in the presence of bulky and electron-rich phosphine ligand is described. In addition, a useful chemoselective coupling of an aryl chloride in the presence of a tosyloxy group was demonstrated. [ABSTRACT FROM AUTHOR]

An efficient and useful catalyst—carbon tetrabromide (CBr4)—was discovered to be highly effective for the acylation of phenols, alcohols, and thiols under metal- and solvent-free conditions. [ABSTRACT FROM AUTHOR]

Metal-free catalytic C–H silylation of a series of aromatic compounds such as N,N-disubstituted anilines with various hydrosilanes has been achieved for the first time using commercially available B(C6F5)3 as a catalyst. This protocol features simple and neutral reaction conditions, high regioselectivity, wide substrate scope (up to 40 examples), Si–Cl bond compatibility, and no requirement for a hydrogen acceptor. [ABSTRACT FROM AUTHOR]

The article discusses a study on the reaction and interaction of compounds in the title to investigate the structural variety and potential biological systems applications. Researchers mixed a red solution with (Et4N)[Tp*WS3 in 5 milliliters of MeCN to excess melamine and 6 milligrams of CuNCS in forming a darker red solution. Findings indicated the location of H atom of the BH group in a difference Fourier map with isotropic and position displacement parameters.

The branching copolymerization of styrene with triethylene glycol dimethacrylate (tri-EGDMA) as the branching agent was carried out using atom transfer radical polymerization (ATRP) in anisole at 90 °C. The resulting copolymers were analyzed using 1H NMR and triple detection size exclusion chromatography (TD-SEC). The NMR analysis shows that the pendent vinyl groups react even in the early stages of the polymerization. Analysis of the changes in the molecular weight and polydispersity of the copolymers suggests that the reaction system contains three components: the primary chains, the slightly branched chains comprising of two primary chains, and the highly branched chains consisting of more than three primary chains. The coupling reaction mainly takes place between the primary chains, resulting in the slightly branched chains in the early stages of the reaction, the weight fraction of the branched chains and the degree of branching increase gradually with monomer conversion, highly branched chains mainly form at relatively high monomer conversions. [ABSTRACT FROM AUTHOR]

A novel N-formylation and related reactions proceed from cyanides promoted by esters. [ABSTRACT FROM AUTHOR]