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A novel mononuclear ruthenium (Ru) complex bearing a PNNP-type tetradentate ligand is introduced here as a self-photosensitized catalyst for the reduction of carbon dioxide (CO2). When the pre-activation of the Ru complex by reaction with a base was carried out, an induction period of catalyst almost disappeared and the catalyst turnover numbers (TONs) over a reaction time of 144 h reached 307 and 489 for carbon monoxide (CO) and for formic acid (HCO2H), respectively. The complex has a long lifespan as a dual photosensitizer and reduction catalyst, due to the sterically bulky and structurally robust (PNNP)Ru framework. Isotope-labeling experiments under 13CO2 atmosphere indicate that CO and HCO2H were both produced from CO2.

Carbon dioxide (CO2) is an attractive renewable one-carbon (C1) feedstock in terms of its earth abundance, low cost, and non-toxicity. Developing new catalytic systems to realize the practical insertion of CO2 into organic molecules has been of great importance for ecological economics. In recent years, outstanding improvements have been carried out in the field of light-driven catalytic carboxylation via the activation of CO2 as the key reagent. In this short review, the recent developments of light-promoted carboxylation utilizing CO2 to synthesize value-added chemicals using a dual visible-light photoredox/transition-metal catalyst or a photoredox catalyst are highlighted.1 Introduction2 Visible-Light-Driven Carboxylation Using Transition-Metal Photocatalysts2.1 Transition-Metal-Catalyzed Carboxylation of Alkenes2.2 Transition-Metal-Catalyzed Carboxylation of C(sp2)–X (X = Cl, Br, OTf) Bonds2.3 Transition-Metal-Catalyzed Carboxylation of Alkynes2.4 Transition-Metal-Catalyzed Carboxylation of Carbons Attached to Nitrogen3 Light-Driven Carboxylation via Organo-Photocatalysis3.1 Photocatalytic Carboxylation of Alkenes3.2 Photocatalytic Carboxylation of C(sp3)–H Bonds4 Conclusion

Hydrogenation of carboxylic acids (CAs) to alcohols represents one of the most ideal reduction methods for utilizing abundant CAs as alternative carbon and energy sources. However, systematic studi...

The redox-neutral addition of α-C–H bonds of acetonitrile and acetone to styrenes was enabled via the hydrogen-atom transfer from relatively acidic and water-miscible C(sp3)–H bonds to an aqueous hydroxyl radical generated cleanly and iteratively by the oxidation of water under silver-nanoparticle-loaded titania photocatalysis without using stoichiometric oxidation agents.

Two-dimensional (2D) boron monosulfide (BS) nanosheets are predicted to have several stable phases and unique electronic structures, endowing them with interesting attributes, including superconducting, thermoelectric, and hydrogen storage properties. In this paper, we report the experimental realization of 2D BS nanosheets by the physical exfoliation of rhombohedral boron monosulfide (r-BS). Moreover, we demonstrate the facile separation of a mixture of 2D BS nanosheets and the r-BS powder in acetonitrile; the former were selectively separated as a dispersion in the supernatant, whereas the latter remained in the precipitate. In addition, density functional theory calculations reveal a clear dependence of the bandgap energy (Eg) on the number of layers of stacked BS nanosheets, where Eg for BS nanosheets is approximately 1.0 eV higher than that for r-BS. Atomic force microscopy, cathode luminescence, ultraviolet-visible absorption spectroscopy, and excitation emission matrix experiments revealed a consistent bandgap difference of approximately 1.0 eV between the BS nanosheets and r-BS. We also demonstrate the applications based on the properties that originated from the difference in the bandgap between r-BS and BS nanosheets using photoelectrochemical current switching. These results indicate that the nanosheet bandgap can be tuned to a desired value by controlling the number of stacked 2D BS nanosheets. Therefore, BS nanosheets are promising non-metal 2D materials for applications requiring bandgap control, such as electronics and photocatalysis.

Hexagonal boron nitride (h-BN) is a layered material that is generating interest in various fields owing to its fascinating properties. We present a multi-stranded analysis of carbon defects in h-BN using intentionally carbon (C)-doped h-BN crystals. Carbon defects were introduced into h-BN crystals synthesized under high-pressure and high-temperature (HPHT) conditions by a process of carbon annealing. We employ an innovative approach to explore impurity states in our C-doped h-BN by assembling it into van der Waals heterostructures with other 2D materials. Attaching graphene as a probe material to determine the impurity states in the h-BN bandgap, we locate an acceptor state above the Dirac point of graphene on C-doped h-BN, which causes anomalous bending in the Landau fan diagram. Furthermore, we adopt tungsten disulfide (WS2) as another probe material and assess the influence of C-doped h-BN on the emission spectrum of the WS2 monolayers. Our work reveals the nature of the carbon impurities in h-BN and also uncovers their effects on adjacent 2D materials.

The atom-efficient formation of amide bonds has emerged as a top-priority research field in organic synthesis, as amide bonds constitute the backbones of proteins and represent an important structural motif in drug molecules. Currently, the increasing demand for novel discoveries in this field has focused substantial attention on this challenging subject. Herein, the degradable 1,3,5-triazo-2,4,6-triphosphorine (TAP) motif is presented as a new condensation system for the dehydrative formation of amide bonds between diverse combinations of aromatic carboxylic acids and amines. The underlying reaction mechanism was investigated, and potential catalyst intermediates were characterized using 31P NMR spectroscopy and ESI mass spectrometry.

A highly efficient tetradentate PNNP-type Ir photocatalyst, Mes-IrPCY2, was developed for the reduction of carbon dioxide. The photocatalyst furnished formic acid (HCO2H) with 87% selectivity toget...

Symmetric secondary amines were synthesized by the self-condensation of primary amines over a palladium-loaded titanium dioxide (Pd/TiO2) photocatalyst. The reactions afforded a series of secondary amines in moderate to excellent isolated yields at ambient temperature (30 °C, in cyclopentyl methyl ether). Applicability for one-pot pharmaceutical synthesis was demonstrated by a photocatalytic reaction sequence of self-condensation of an amine followed by N-alkylation of the resulting secondary amine with an alcohol.

Amines in heteroaromatic systems and pharmaceutical intermediates were functionalized through N-methylation with methanol using a palladium-loaded titanium dioxide (Pd/TiO2) photocatalyst. This method provides access to a series of tertiary N-methylamines bearing N-, O-, and/or S-containing heteroaromatic functionalities from primary/secondary amines and methanol under mild reaction conditions. Facile syntheses of several pharmaceuticals containing N-methyl or ethyl groups, as well as related deuterated drugs, was achieved through the late-stage functionalization of amines., ファイル公開：2019-11-05

Carboxylic acids are ubiquitous in bio-renewable and petrochemical sources of carbon. The hydrogenation of carboxylic acids to alcohols generates water as the only by-product, and thus represents a sustainable method for the production of these alternative energy carriers/platform chemicals on a large scale. Herein, we offer a brief account of the development of this new concept and molecular insights into cationic mononuclear low- and high-valent transition-metal complexes for the hydrogenation of carboxylic acids., first published on 03 Oct 2018 ファイル公開日：2019-10-03

The Krebs cycle is the fuel/energy source for cellular activity and therefore of paramount importance for oxygen-based life. The cycle occurs in the mitochondrial matrix, where it produces and transfers electrons to generate energy-rich NADH and FADH2, as well as C4-, C5-, and C6-polycarboxylic acids as energy-poor metabolites. These metabolites are biorenewable resources that represent potential sustainable carbon feedstocks, provided that carbon-hydrogen bonds are restored to these molecules. In the present study, these polycarboxylic acids and other mitochondria-relevant metabolites underwent dehydration (alcohol-to-olefin and/or dehydrative cyclization) and reduction (hydrogenation and hydrogenolysis) to diols or triols upon reaction with H2, catalyzed by sterically confined iridium–bipyridyl complexes. The investigation of these single–metal site catalysts provides valuable molecular insights into the development of molecular technologies for the reduction and dehydration of highly functionalized carbon resources.

Silver(I)-loaded titanium dioxide (AgNO3/TiO2) catalyzes the direct N-methylation of amino acids with methanol under irradiation with UV light. This method produces a variety of N-methyl and N,N-dimethyl amino acids with retention of their optical purity.

Despite the continuing popularity of radical reactions in organic synthesis, much remains to be explored in this area. Herein, we describe how spatiotemporal control can be exerted over the formation and reactivity of divergent exchangeable formamide radicals using nickel complexes with a semiconductor material (TiO2) under irradiation from near-UV–Vis light. Depending on the bipyridine ligand used and the quantity of the nickel complex that is hybridized on or nonhydridized over the TiO2 surface, these radicals selectively undergo substitution reactions at the carbon center of carbon–bromine bonds that proceed via three different pathways. As the scalable production of formamides from CO2 does not produce salt waste, these methods could add a new dimension to the search for carbon neutrality through the indirect incorporation of CO2 into organic frameworks.

The Krebs cycle is the fuel/energy source for cellular activity, and therefore of paramount importance for oxygen-based life. The cycle occurs in the mitochondrial matrix, where it produces and transfers electrons to generate energy-rich NADH and FADH2, as well as C4-, C5-, and C6-polycarboxylic acids as energy-poor metabolites. These metabolites are bio-renewable resources that represent potential sustainable carbon feedstocks, provided that carbon–hydrogen bonds are restored to these molecules. In the present study, polycarboxylic acids of the Krebs cycle and other mitochondria-relevant metabolites are dehydrated and reduced to diols or triols upon reaction with H2, catalyzed by sterically confined iridium-bipyridyl complexes.

Allogeneic cultured epidermis (allo-CE) is a cultured keratinocyte sheet manufactured from donor cells and promotes wound healing when used in deep dermal burns, donor sites, and chronic ulcers and serves as a wound dressing. Allo-CE is usually cryopreserved to be ready to use. However, the cryopreservation procedure will damage the cell viability, and the influence of Allo-CE, according to its viability or wound healing process, has not been evaluated sufficiently. In this study, we aimed to prove the influence of keratinocyte viability contained in allo-CEs on wound healing. We prepared CEs with Green’s method using keratinocytes obtained from a polydactyly patient and then prepared four kinds of CEs with different cell viabilities [fresh, cryopreserved, frozen, and FT (freeze and thaw)]. The cell viabilities of fresh, cryopreserved, frozen, and FT CEs were 95.7%, 59.9%, 16.7%, and 0.0%, respectively. The four CEs had homogeneous characteristics, except for small gaps found in the FT sheet by transmission electron microscopy observation. The four CEs were applied on the full-thickness skin defect of diabetic mice (BKS.Cg-Dock 7m +/+ Leprdb/Jcl), and the wound area and neoepithelium length were evaluated on days 4, 7, and 14. As a result, FT CEs without viable cells similarly promoted epithelialization on days 4 and 7 (p

Tetrakis(dimethylamido)diboron and tetrahydroxydiboron are herein reported as new catalysts for the synthesis of aryl amides by catalytic condensation of aromatic carboxylic acids with amines. The developed protocol is both simple and highly efficient over a broad range of substrates. This method thus represents an attractive approach for the use of diboron catalysts in the synthesis of amides without having to resort to stoichiometric or additional dehydrating agents., ファイル公開：2019-08-03

We report herein a regio- and stereoselective photocatalytic hydrogenolysis of allylic alcohols to form unsaturated hydrocarbons employing a palladium(II)-loaded titanium oxide; the reaction proceeds at room temperature under light irradiation without stoichiometric generation of salt wastes. Olefin and saturated alcohol moieties tolerated the reaction conditions. Hydrogen atoms were selectively incorporated into less sterically congested carbons of the allylic functionalities. This protocol allowed a short-step synthesis of (S)-(+)-lavandulol from (R)-(-)-carvone by avoiding otherwise necessary protection/deprotection steps.

A brief account of our recent work on the chemo-, regio- and stereoselective photocatalytic hydrogenolysis of allylic alcohols to alkenes promoted by palladium-loaded titanium oxide (Pd/TiO2) photocatalysts is presented. Since methanol is employed as the reducing agent, the method does not involve stoichiometric generation of salt waste. The photocatalytic hydrogenolysis proceeds at room temperature, and is compatible with the presence of functional groups such as C=C double bonds and hydroxyl groups at non-allylic positions. The regioselectivity is predictable: the hydrogen atom is predominantly incorporated into the sterically less hindered carbon atom of the allylic moiety. This protocol should provide straightforward green access to a range of platform chemicals (exemplified by the two-step synthesis of propylene from glycerol) and fine chemicals [e.g. (S)-(+)-lavandulol from (R)-(–)-carvone] without the need for protection/deprotection steps.

We study stabilities and electronic properties of several environmental polluting or toxic gas molecules (CO, CO2, NO, and NO2) adsorbed on B and N atoms in bilayer graphene using first-principles electronic-structure calculations. We find that NO and NO2 molecules can be bound chemically on B-doped bilayer graphene with large adsorption energies, while CO and CO2 molecules are not adsorbed chemically on B-doped one. In the case of the N-doped graphene, all four gases do not bind with chemical bonds but adsorb rather physically with small adsorption energies at long distances between gases and graphene. The adsorptions of NO and NO2 molecules on B-doped bilayer graphene induce the acceptor states above the Fermi energy, and we also find that the charge transfer takes place when the NO and the NO2 molecules are adsorbed. Thereby, the B-doped bilayer graphene is expected to be useful for NO and NO2 gas sensor materials.

Widespread of fuel cells are strongly desired from the point of reducing the GHG and for clean environment. In order to achieve these, reducing the cost of the fuel cell vehicle is needed and from this point, higher operating temperatures of PEFC can contribute for designing compact and simple cooling system. We have been developing variety of new Perfluorosulfonic acid (PFSA) ionomers having high ion exchange capacity (IEC) and other properties required for each the membrane and the electrolyte in the electrodes. The ionomer with high proton conductivity was tested by copolymerization of tetrafluoroethylene with a new bifunctional fluorosulfonyl monomer 1. The ion exchange capacity was 1.58 meq/g and the water uptake after immersion in hot water at 80 °C for 16 hours was much lower compared to that of conventional ionomer. Reduction in Pt loading in the cathode is another requirement for PEFC to reduce the cost. Especially at higher temperature and lower RH conditions under which the flux of oxygen to the Pt surface through the ionomer in the electrode could be the rate limiting factor for the oxygen reduction reaction (ORR). In order to increase the oxygen flux to Pt surface, the use of ionomers having higher oxygen permeability can be a solution. We have designed and synthesized various ionomers based on a general rule that the lower the density of a fluorinated polymer, the higher the oxygen permeability. One of the newly prepared ionomer having lower density showed more than 2 times higher the oxygen permeability 2 at low RH conditions. The use of this high oxygen permeable ionomer at cathode showed the possibility of achieving the same cell voltage with half the amount of Pt loading. We see that the ionomer plays an important row in developing PEFC achieving the requirements from the market. The ionomer can also be used in the micro porous layers (MPLs) between the catalyst layers and the Gas diffusion substrate to create hydrophilic MPLs. Conventionally, hydrophobic MPLs were applied between the GDM and the catalyst layer to prevent flooding due to excess water in the electrode. But the hydrophobicity of the MPL is not favorable when the cell is operating under a dry condition. We have been reporting the use of hydrophilic MPL between the GDM and the catalyst layer 3. It can control the water balance in the MEA, achieving higher performance under low RH conditions without facing the low performance due to mass transfer issue at wet conditions. This hydrophilic MPL was used in the cathode in combination with a high proton conductive membrane, and the MEA showed excellent performance under a very dry condition. We are continuously making efforts developing PEFC materials getting into the next stage. References 1. A.Watakabe, H Yamamoto, M Iwaya, S Saito, K Yamada, S Hommura and T Shimohira, Fluoropolymer (2012) 2. K. Yamada, S. Hommura, and T. Shimohira, ECS Trans., 50 (2), 1495 (2013). 3. T. Tanuma and S. Kinoshita, J. Electrochem. Soc., 161 (1), F94 (2014).

N-Allylamines were employed for the diastereoselective synthesis of 8-bromo-substituted, cis-configured perhydroquinoxalines and β-bromoalcohols. The yield and constitution of the products depend considerably on the functionalization of the allylic N-atom. Herein the reaction of glycine-derived cyclohex-2-enamines under bromolactamization conditions (LiOtBu, NBS) is reported. Methyl carbamate led diastereoselectively to the cis-configured perhydroquinoxaline , whereas the amides and provided cis,trans-configured -bromoalcohols and . Based on high level theoretical calculations (DFT) factors controlling the cyclization of lithiated intermediates and the relative energies of possible products are discussed.

Dehydrogenation reaction of primary aliphatic alcohols to aldehydes and molecular hydrogen was achieved under UV–vis light irradiation in the presence of gold-loaded titanium dioxide (Au/TiO2) photocatalysts.

Direct functionalization of amino groups in complex organic molecules is one of the most important key technologies in modern organic synthesis, especially in the synthesis of bio-active chemicals and pharmaceuticals. Whereas numerous chemical reactions of amines have been developed to date, a selective, practical method for functionalizing complex amines is still highly demanded. Here we report the first late-stage N-alkylation of pharmaceutically relevant amines with alcohols at ambient temperature. This reaction was achieved by devising a mixed heterogeneous photocatalyst in situ prepared from Cu/TiO

Direct functionalization of amino groups in complex organic molecules is one of the most important key technologies in modern organic synthesis, especially in the synthesis of bio-active chemicals and pharmaceuticals. Whereas numerous chemical reactions of amines have been developed to date, a selective, practical method for functionalizing complex amines is still highly demanded. Here we report the first late-stage N-alkylation of pharmaceutically relevant amines with alcohols at ambient temperature. This reaction was achieved by devising a mixed heterogeneous photocatalyst in situ prepared from Cu/TiO2 and Au/TiO2. The mixed photocatalytic system enabled the rapid N-alkylation of pharmaceutically relevant molecules, the selective mono- and di-alkylation of primary amines, and the non-symmetrical dialkylation of primary amines to hetero-substituted tertiary amines.

Layered electrides, as typified by ${\mathrm{Ca}}_{2}\mathrm{N}$, are unconventional quasi-two-dimensional metals with low work functions, in which the conduction electrons are localized between the cation layers as well as outside the surface. We have investigated the electronic structure of the interface between a layered electride and another material, using graphene on ${\mathrm{Ca}}_{2}\mathrm{N}$ as an example. Our first-principles calculation shows that a graphene layer on ${\mathrm{Ca}}_{2}\mathrm{N}$ remains flat and is doped to an extremely high density of $n=5\ifmmode\times\else\texttimes\fi{}{10}^{14}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}$ with its Fermi level (${E}_{F}$) aligned with the logarithmically divergent van Hove singularity (VHS) at a saddle point of graphene's ${\ensuremath{\pi}}^{*}$ band. This finding shows that graphene/${\mathrm{Ca}}_{2}\mathrm{N}$ is an ideal testing ground for the exploration of the many-body ground states, most notably superconducting states ($p+ip$ wave, $d$ wave, and $f$ wave), predicted to appear when ${E}_{F}$ is close to a VHS. The work function decreases abruptly upon monolayer attachment but reverts to that of ${\mathrm{Ca}}_{2}\mathrm{N}$ upon bilayer attachment. This peculiar behavior is explained in terms of the distinctive electronic structures of the constituent materials and their bonding.

cis,cis-Configured perhydroquinoxaline-5-carbonitrile 10 was synthesized stereoselectively by ditosylation of trans,cis-2,3-dihydroxycyclohexane-1-carbonitrile 4 and subsequent reaction with ethylenediamine. The diol precursor 4 was stereoselectively obtained by regioselective opening of the epoxide 3 with KCN in water avoiding hazardous Et2AlCN.

First-principles electronic-structure calculations have been performed to investigate energetics and electronic properties of boron (B) and nitrogen (N) defects in bilayer graphene. It is found that the formation energies for N-doped AB -stacked bilayers vary depending on dopant sites, whereas those for B-doped ones show almost site-independent behavior. From results of energy-band structure, B-doped and N-doped bilayer graphenes exhibit p -type and n -type electronic properties, respectively, with carriers on both two layers. It is also found that the boron and the nitrogen defects are observable in scanning tunneling microscopy (STM) images, while AA - and AB -stacking patterns of doped bilayer graphene exhibit similar STM images.

A novel method to prepare microstructured polymer brushes using TiO2 nanoparticles and photocatalytic microcontact printing is described. It is shown that ethanol amine can be polymerized to linear polyethyleneimine (PEI) driven by the photocatalytic action of TiO2. Upon UV irradiation during microcontact printing of ethanol amine with a stamp coated with TiO2 nanoparticles, patterned polymer brushes with a length of around 50 nm are obtained.

Herein, catalytic fluoride (F−) is demonstrated to be a trigger for dehydrative immobilization of atmospheric pressure CO2, such that reaction of CO2 with β-amino alcohols derived from natural amino acids gives optically pure oxazolidinones in high yields. A synergistic combination of fluoride and organosilicon agents (e.g., Bu4NF + Ph3SiF or siloxanes) enhances the catalytic activity and functional group compatibility. This system lies at the interface between homogenous and heterogeneous catalysis, and may prove useful for the development of recoverable/reusable siloxane-based CO2 immobilization materials.

Carboxylic acids (CAs) are one of the most ubiquitous and important chemical feedstocks available from biorenewable resources, CO2, and the petrochemical industry. Unfortunately, chemoselective catalytic transformations of CH n CO2H (n = 1–3) groups into other functionalities remain a significant challenge. Herein, we report rheniumV complexes as extremely effective precatalysts for this purpose. Compared to previously reported heterogeneous and homogeneous catalysts derived from high- or low-valent metals, the present method involves a α-C–H bond functionalization, a hydrogenation, and a hydrogenolysis, which affords functionalized alcohols with a wide substrate scope and high chemoselectivity under relatively mild reaction conditions. The results represent an important step toward a paradigm shift from ‘low-valent’ to ‘high-valent’ metal complexes by exploring a new portfolio of selective functional group transformations of highly oxygenated organic substrates, as well as toward the exploitation of CAs as a valuable biorenewable feedstock.

Amides are ubiquitous and abundant in nature and our society, but are very stable and reluctant to salt-free, catalytic chemical transformations. Through the activation of a “sterically confined bipyridine–ruthenium (Ru) framework (molecularly well-designed site to confine adsorbed H2 in)” of a precatalyst, catalytic hydrogenation of formamides through polyamide is achieved under a wide range of reaction conditions. Both C=O bond and C–N bond cleavage of a lactam became also possible using a single precatalyst. That is, catalyst diversity is induced by activation and stepwise multiple hydrogenation of a single precatalyst when the conditions are varied. The versatile catalysts have different structures and different resting states for multifaceted amide hydrogenation, but the common structure produced upon reaction with H2, which catalyzes hydrogenation, seems to be “H–Ru–N–H.”

We propose a systematic approach to obtain various forms of insulating titanium oxynitrides Ti$_{n}$N$_{2}$O$_{2n-3}$ and we conduct a detailed study on its $n=2$ case, Ti$_{2}$N$_{2}$O. We study the energetics and the electronic structures of Ti$_{2}$N$_{2}$O and compare these results with those of pristine and nitrogen-doped TiO$_{2}$ within the framework of the density-functional theory (DFT) and the GW approximation. We find that Ti$_{2}$N$_{2}$O is semiconducting with the calculated band-gap of 1.81 eV, which is significantly smaller than those of pristine TiO$_{2}$ rutile (3.14 eV) or anatase (3.55 eV). Furthermore, the reduction of the band-gap of Ti$_{2}$N$_{2}$O is realized not by lowering of the conduction-band minimum but by rising the valence-band maximum. Therefore the proposed Ti$_{2}$N$_{2}$O has suitable band-edge alignment for water-splitting photocatalysis. Finally, total energy calculations indicate that Ti$_{2}$N$_{2}$O is potentially easier to synthesize than nitrogen-doped TiO$_{2}$. Based on these results, we propose Ti$_{2}$N$_{2}$O as a promising visible-light photocatalytic material., 10 pages, 7 figures

Compounds based on the pyrroloquinoxaline system can interact with serotonin 5-HT3 , cannabinoid CB1 , and μ-opioid receptors. Herein, a chiral pool synthesis of diastereomerically and enantiomerically pure bromolactam (S,R,R,R)-14A is presented. Introduction of the cyclohexenyl ring at the N-atom of (S)-proline derivatives 8 or methyl (S)-pyroglutamate (12) led to the N-cyclohexenyl substituted pyrrolidine derivatives 4 and 13, respectively. All attempts to cyclize the (S)-proline derivatives 4 with a basic pyrrolidine N-atom via [3 + 2] cycloaddition, aziridination, or bromolactamization failed. Fast aromatization occurred during treatment of cyclohexenamines under halolactamization conditions. In contrast, reaction of a 1:1 mixture of diastereomeric pyroglutamates (S,R)-13bA and (S,S)-13bB with LiO(t) Bu and NBS provided the tricyclic bromolactam (S,R,R,R)-14A with high diastereoselectivity from (S,R)-13bA, but did not transform the diastereomer (S,S)-13bB. The different behavior of the diastereomeric pyroglutamates (S,R)-13bA and (S,S)-13bB is explained by different energetically favored conformations.

Photochemical transformation of biomass-derived or renewable substances with promising scalability is an important challenge for promoting green and sustainable chemistry. We report here that photocatalytic transfer hydrogenolysis of allyl alcohol (obtained from glycerol) gives potentially sustainable propylene with high chemo- and redox selectivity, promoted by powdered Pd/TiO2 in CH3OH (obtained from CO2) under near-ultraviolet–visible light irradiation (λ > 365 nm) at ambient temperature.

We report energetics and scanning tunneling microscopy (STM) images of boron and nitrogen defects in bilayer graphene using a first-principles density-functional study. It is found that the formation energies of N-doped AB-stacked bilayer graphene depend on the substitution sites, while those of B-doped one possess almost the same values without depending on the substitution sites. The STM images of B and N defects in not only AB-stacked but also AA-stacked bilayer graphene are calculated. The STM images near B and N defects in upper layers of AA- as well as AB-stacked bilayer graphenes are found to be similar to each other, whereas those of undoped lower layers show different images.

Dehydrative synthesis of oxazolidinones from amino alcohols and CO2 was achieved in the presence of alkali metal carbonates such as Cs2CO3 as catalyst. It is noteworthy that 1 atm of CO2 is enough for the reaction to proceed and no special dehydrating agent is required in this system. A mechanstic study showed that the OH of amino alcohol acts as nucleophile and the OH in the carbamic acid moiety is liberated during the cyclization process.

A general method for catalytic hydrogenation of unactivated amides was achieved. During the catalyst induction period, a novel structural change was observed involving full hydrogenation of the interior unsaturated bonds of the pyridines of the Ru-containing catalyst precursor. Based on this observation, the mechanism of amide hydrogenation may involve a two-step pathway, wherein the Ru catalyst having an H–Ru–N–H functionality is generated in the first step, followed by the amide carbonyl group interacting with the outer, rather than the inner, sphere of the Ru catalyst.

A virtually salt-free and straightforward bimolecular assembly giving N-unsubstituted pyrroles through fully unmasked α-amino aldehydes, which was enabled by the dual effects of a catalytic ruthenium complex and an alkali metal base, is reported. Either solvent-free or acceptorless dehydrogenation facilitates high atom, step, and pot economy, which are otherwise difficult to achieve in multistep operations involving protection/deprotection.

D-(+)-Camphor forms the enamine 2 with piperidine. Compound 2 adds HB(C(6)F(5))(2) at the enamine carbon atom C3 to form a Lewis acid/Lewis base adduct (exo-/endo-isomers of 3). Exposure of 3 to dihydrogen (2.5 bar, room temperature) leads to heterolytic splitting of H(2) to form the H(+)/H(-) addition products (4, two diastereoisomers) of the "invisible" frustrated Lewis pairs (5, two diastereoisomers) that were apparently generated in situ by enamine hydroboration under equilibrium conditions.

We have developed a new method for the direct aldol condensation of unactivated amides using 1,3,5-triazo-2,4,6-triphosphorine-2,2,4,4,6,6-hexachloride (TAPC)-based phosphorous/SO 4 2− catalysis. The SO 4 2− species in a reaction mixture enhances the reaction rate of the catalysis. In principle, no metal sources are required for the generation of the catalyst, and there is no requirement for the use of stoichiometric quantities of an acid or base. This catalyst system is operative under relatively acidic conditions. One major advantage of carrying out the reaction under acidic conditions is that both aldehydes and acetals are capable of undergoing carbon–carbon bond formation at the α-carbon of amide carbonyl groups through dehydration.

We present first-principles density functional calculations that clarify the electronic properties of carbon defects in hexagonal boron nitride $(h$-BN) monolayers under biaxially applied strains. We find that strain can control the ionization energies of both donor and acceptor states. Furthermore, we also find that strain can lead to the dramatic change in conduction channel properties of donor states due to the interchange of the conduction-band-minimum state with the nearly-free-electron state. We also report the simulated scanning tunneling microscopy (STM) images of carbon defects in $h$-BN monolayers for experimental identification of those defects. We show that the STM images strongly reflect distinctive spatial distributions of local density of states around carbon defects depending on the substitution sites and thereby they could be identified by using STM experiments.

A VeraCode-allele-specific primer extension (ASPE) method was applied to the detection and genotyping of human papillomavirus (HPV)-DNA. Oligonucleotide primers containing HPV-type-specific L1 sequences were annealed to HPV-DNA amplified by PGMY-PCR, followed by ASPE to label the DNA with biotinylated nucleotides. The labeled DNA was captured by VeraCode beads through hybridization, stained with a streptavidin-conjugated fluorophore, and detected by an Illumina BeadXpress® reader. By using this system, 16 clinically important HPV types (HPV6, 11, 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68) were correctly genotyped in a multiplex format. The VeraCode-ASPE genotyping of clinical DNA samples yielded identical results with those obtained by validated PGMY-reverse blot hybridization assay, providing a new platform for high-throughput genotyping required for HPV epidemiological surveys.

The present new method for the cross-coupling of two different alcohols is achieved in the presence of H2 using catalytic amounts of CuBr and NaOH affording longer-chain alcohols.

The reaction of primary and secondary amines with benzylic alcohols (II) under thermal conditions provides a synthesis of higher amines.

We study the structural phase transition of orientationally ordered simple-cubic (sc) C 60 under pressure by using the tight-binding molecular dynamics method. We investigate the system under five pressure values, 10, 20, 30, 40, and 50 GPa. Under 10 and 20 GPa, sc C 60 transforms into a new sc three-dimensional (3D) C 60 polymer. We study the structural stability as well as the electronic properties of this sc 3D C 60 polymer using the density-functional total-energy calculation with the local-density approximation, and this new sc 3D polymer phase is predicted to be highly stable. Interestingly, the lattice constant of this new sc 3D polymer phase is found to be close to those of both the face-centered-cubic (fcc) 3D phase of Yamanaka et al. [J. Am. Chem. Soc. 130 (2008) 4303] and that of Mezouar et al. [Phys. Rev. B 68 (2003) 193414]. In addition, the material is predicted to be a semiconductor. Moreover, it is even found from simulated structure factors for this new sc 3D polymer phase that this new sc 3D polymer phase might satisfy the extinction rule of fcc when the antiphase boundary defects exist in the crystal, indicating that this phase can be a candidate for one of main phases in the experimental samples.