bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nickel‐Catalyzed Synthesis of Ketones from Alkyl Halides and Acid Chlorides: Preparation of Ethyl 4‐Oxododecanoate
Authors: Wotal Alexander C. , Batesky Donald C. , Weix* Daniel J. 
Published: March 2017

Abstract
Prevalence of alkyl alkyl ketones in natural products, their use in biological probes, and their versatility as intermediates in organic synthesis, a wide variety of methods have been developed to access them. The most commonly used methods are the addition of a reactive organometallic reagent to an aldehyde followed by oxidation and the addition of pre‐formed organometallic nucleophiles to carboxylic acid derivatives. While both of these protocols are effective, the organometallic reagents can be limiting with complex, functionalized molecules. This article discusses nickel‐ catalyzed synthesis of ketones from alkyl halides and acid chlorides.
Intermolecular [2+2] Cycloaddition of Alkynes with Alkenes Catalyzed by Gold(I)
Authors: de Orbe M. Elena , Echavarren* Antonio M. 
Published: March 2017

Abstract
The synthesis of cyclobutenes by metal‐catalyzed intermolecular [2+2] cycloaddition of alkynes with alkenes is normally restricted to strained bicyclic olefins. This article describes gold(I)‐catalyzed intermolecular [2+2] cycloaddition of terminal alkynes with differentlysubstituted alkenes as an important method for the formation of cyclobutenes.
Photochemical Benzannulation of
N
‐Phosphoryl Ynamides and α‐Diazo Ketones in Continuous Flow
Authors: Read John M. , Wang Yu‐Pu , Danheiser* Rick L. 
Published: March 2017

Abstract
The article describes photochemical benzannulation of “Second‐generation” benzannulation based on vinylketenes can be conveniently performed under conditions of continuous flow using readily available photochemical equipment and a syringe pump. The high throughput of this reactor allows the benzannulation to be carried out on a multigram scale with reaction times on the order of several hours.
Trifluoromethylation of Aryl Iodides Catalyzed by the Copper(I)‐Phen Complex
Authors: Shimizu Naoto , Kondo Hideaki , Oishi Masahiro , Fujikawa Kenichi , Komoda Kazuki , Amii* Hideki 
Published: March 2017

Abstract
The structural motifs of trifluoromethylated aromatics (Ar‐CF3) have been widely employed in various industrial fields. The high lipophilicity, strong electron‐withdrawing ability, and characteristic size of the trifluoromethyl group is a key influence in the design of pharmaceuticals, agrochemicals, dyes, liquid crystals, and polymers. Therefore, a great deal of attention has been paid to convenient protocols of introducing trifluoromethyl groups into aromatic rings. With respect to the high regiochemical fidelity in aromatic substitution, the cross‐coupling of aryl halides with CF3Cu is one of the most powerful and versatile methods to construct trifluoromethylated aromatics.
Copper‐catalyzed Cyanation of Alkenyl Iodides
Authors: Nitelet Antoine , Zahim Sara , Theunissen Cédric , Pradal Alexandre , Evano* Gwilherm 
Published: March 2017

Abstract
Copper‐catalyzed vinylic version of the Rosenmund‐von Braun cyanation reaction was developed and provides an efficient entry to both E‐ and Z‐ polysubstituted alkenyl nitriles. The cyanation of (Z)‐1‐iodooct‐1‐ene described in this article is illustrative of this reaction which can be conveniently performed on a multi‐gram scale.
Visible Light Photocatalysis of Radical Cation Diels–Alder Cycloadditions: Preparation of Tris(2,2’‐bipyrazyl) Ruthenium(II) Bis(tetrakis(3,5‐bis(trifluoromethyl)phenyl)borate)
Authors: Lies Shane D. , Lin Shishi , Yoon* Tehshik P. 
Published: March 2017

Abstract
The article describes visible light photocatalysis of radical cation Diels–Alder cycloadditions. The electron‐deficient bipyrazyl ligands render this photocatalyst a substantially more powerful photooxidant than the more common parent tris(bipyridyl) complex. Due to the attractive photoredox properties of Ru(bpz)3 2+ coupled with its chemical stability and long excited state lifetime, this photocatalyst has proven to be powerfully enabling in a variety of photooxidative transformations. These have included oxidative [3+2] cycloadditions of phenols, thiol–ene reactions, and aerobic cyclooxygenation reactions, among others. However, previously reported methods for the synthesis of the bipyrazyl ligand are not easily scalable or provide poor yields. The improved method described in this manuscript is based upon optimized conditions reported recently by our group.
Preparation of 1,5‐Dioxaspiro[5.5]undecan‐3‐one
Authors: Craig Robert A. , Smith Russell C. , Pritchett Beau P. , Estipona Benzi I. , Stoltz* Brian M. 
Published: March 2017

AbstractThe article describes the preparation of 1,5‐Dioxaspiro[5.5]undecan‐3‐one. Synthesis of the analogous diethyl ketal product has been accomplished using 3,3‐dimethoxypentane in place of 1,1‐dimethoxycyclohexane. The utility of ketodioxanones as nucleophiles in enantioselective palladium‐catalyzed allylic alkylations, diastereoselective alkylations, α,α’‐annulations, and organocatalyic stereoselective aldol condensations. The products of these transformations have been successfully applied to the synthesis of a variety of simple and complex carbohydrates and biologically active natural products.
Potassium
tert
‐Butoxide–Catalyzed Dehydrogenative Cross‐Coupling of Heteroarenes with Hydrosilanes
Authors: Toutov Anton A. , Liu Wen‐Bo , Stoltz* Brian M. , Grubbs* Robert H. 
Published: March 2017

Abstract
Heteroarylsilanes are valuable synthetic intermediates which are widely used in complex molecules synthesis, medicinal chemistry and drug discovery, and advanced materials and polymers synthesis. The article describes the method for dehydrogenative cross‐coupling reaction using potassium tert‐butoxide as a catalyst that provides a unique way to access a wide array of heteroarylsilanes. The procedure reported here is applicable to a range of heteroarenes and hydrosilanes, giving access to synthetically valuable heteroarylsilanes on multigram scales.
Synthesis of α‐Carboline
Authors: He Linli , Allwein Shawn P. , Dugan Benjamin J. , Knouse Kyle W. , Ott Gregory R. , Zificsak* Craig A. 
Published: March 2017

Abstract
The article reports synthesis of α‐Carboline. This heterocycle has found utility as a building block in natural product and medicinal chemistry as well as in optoelectronic materials. Literature procedures for the preparation of 2 fall into two general catagories: thermolysis of a pyridylbenzotriazole, with extrusion of nitrogen leading to bond formation (a modified Graebe‐Ullman reaction) or formation of the C4a‐C4b bond from an aryl halide–aryl‐H intramolecular coupling.
Nickel‐Catalyzed Suzuki–Miyaura Coupling int‐Amyl Alcohol for the Preparation of 5‐(Furan‐3‐yl)pyrimidine
Authors: Hie Liana , Garg* Neil K. 
Published: March 2017

AbstractTransition metal‐catalyzed cross‐couplings are versatile methods for carbon–carbon and carbon–heteroatom bond formation. Traditionally, palladium catalysts have been most commonly utilized for this type of transformation; however, there has been a significant interest in the development of cross‐coupling reactions that rely on non‐precious metal catalysts. In particular, nickel has emerged as an alternative to palladium due to several factors. The article reports nickel‐catalyzed Suzuki–Miyaura coupling int‐amyl alcohol for the preparation of 5‐(Furan‐3‐yl)pyrimidine.
Preparation of (S)‐Nonafluorobutanesulfinamide
Authors: Wangweerawong Apiwat , Kolmar Scott , Ellman* Jonathan A. 
Published: March 2017

Abstract
The article reports preparation of (S)‐Nonafluorobutanesulfinamide. For the preparation of the perfluorobutanesulfinamide, we focused on Senanayake's chiral sulfinyl transfer auxiliary approach. The two‐step synthesis of perfluorobutanesulfinamide from Senanayakes's 2‐aminoindanol‐derived sulfinyl transfer reagent described in this report proceeds in good overall yield and with excellent enantiomeric purity. The described method uses inexpensive nonafluoro‐1‐iodobutane as a starting input and requires only one straightforward flash column chromatography. Additionally, the chiral auxiliary 3 can be recovered in good yields.
Preparation of 1‐methylimidazole‐N‐oxide (NMI‐O)
Authors: Murray James I. , Spivey* Alan C. 
Published: March 2017

AbstractThe article describes the preparation of 1‐methylimidazole‐N‐oxide.N‐heterocycles were generally more efficient than theirN‐oxide analogues in the acylation process,N‐oxides were generally more active for the sulfonylation and silylation of alcohol derivatives. In particular, 1‐methylimidazole‐N‐oxide (NMI‐O) was found to be a highly efficient catalyst both for sulfonylation and silylation. NMI‐O was found to be the only amine orN‐oxide Lewis basic organocatalyst capable of promoting the efficient silylation of tertiary alcohol derivatives with low catalyst loading (2.5 mol%) and under mild reaction conditions.
Preparation of 1,1‐Difluoroallenes by Difluorovinylidenation of Carbonyl Compounds
Authors: Fuchibe Kohei , Abe Masashi , Oh Ken , Ichikawa* Junji 
Published: March 2017

Abstract
The article reports the preparation of 1,1‐difluoroallenes by difluorovinylidenation of carbonyl cmpounds. 1,1‐Difluoroallenes have been synthesized via either the formation of the second C–C double bond in fluorinated alkenes or the rearrangement of the C–C triple bonds in fluorinated alkynes.
Synthesis of Cyclobutanes by Lewis Acid‐Promoted Ketene‐Alkene [2+2] Cycloadditions
Authors: Rasik Christopher M. , Salyers Eleni M. , Brown* M. Kevin 
Published: March 2017

Abstract
When compared to thermally‐induced reactions, Lewis acid‐promoted variants give rise to increased yields for unactivated alkenes. The article describes the synthesis of cyclobutanes by Lewis acid‐promoted ketene‐alkene [2+2] cycloadditions.
Asymmetric Synthesis of 2‐Thiocyanato‐2‐(1‐aminoalkyl)‐substituted 1‐Tetralones and 1‐Indanones with Tetrasubstituted Carbon Stereogenic Centers via Cooperative Cation‐Binding Catalysis
Authors: Yu Lei , Wu Xiaoyan , Kim Mun Jong , Vaithiyanathan Venkataramasubramanian , Liu Yidong , Tan Yu , Qin WenLing , Song Choong Eui , Yan Hailong 
Published: March 2017

AbstractIn this study, the concept of cooperative cation‐binding catalysis was applied for direct generation of two contiguous trisubstituted and tetrasubstituted stereogenic centers. Using the readily accessible chiral oligoethylene glycol (oligoEG) as a cation‐binding catalyst, asymmetric Mannich reactions of α‐thiocyanato cyclic ketones as Mannich donors were performed with α‐amidosulfones as the bench‐stable imine precursors in the presence of potassium fluoride as the base, affording 2‐thiocyanato‐2‐(1‐aminoalkyl)‐substituted 1‐tetralones and 1‐indanones possessing fully substituted C–SCN centers. The salient features of this process include (i) a transition metal‐free and operationally simple procedure, (ii) direct use of α‐amidosulfones as bench‐stable precursors of sensitive imines, (iii) direct enolization of racemic cyclic α‐thiocyanato ketones and (iv) excellent stereoselectivity with up to 99% ee and >20:1 diastereoselectivity (anti:syn). This protocol is easily scalable and provides a new approach for the syntheses of some biologically relevant products possessing fully substituted C–SCN centers.magnified image
Shifting diet, shifting culture? A bioarchaeological approach to island dietary development on Iron‐Age Öland, Baltic Sea
Authors: Wilhelmson Helene 
Published: March 2017

AbstractObjectivesThe diet and subsistence in Iron‐Age Öland is debated as earlier studies and different archaeological sources seemingly provide conflicting interpretations. The objectives of this study are therefore to: (i) add new insights on diet and (ii) investigate the chronological variation in detail. It is common in studies of diet to investigate differences between datasets defined by archaeological periods (determined by artefact typology), but it is rare to explore whether these dietary changes are, in fact, well correlated with these temporal categories or not.Materials and methodsStable isotope analysis of 108 individuals and 25 animals was used to interpret diet in comparison with data from earlier studies. Different values of TLE (Trophic Level Effect) for δ15N were compared for interpretations of diet. Of the 108 individuals, 42 were subjected to 14C analysis in this study.ResultsThe isotopes from Iron‐Age animals on Öland indicate that the local, contemporary ecology is specific. The human isotope values show chronological development both when pooled in chronological groups by typology and by more specific 14C chronology.DiscussionThe new samples of animals as well as the use of 5‰ TLE for δ15N values results in the diet reinterpreted as mainly domesticate‐based, with at least two shifts in diet occurring in the Iron Age. The use of 14C dates in connection with the stable isotope results indicates a dietary transition occurring between 200 BC and AD 200, a date range that spans two typologically determined time periods.
Quantification of the position and depth of theflexor hallucis longusgroove in euarchontans, with implications for the evolution of primate positional behavior
Authors: Yapuncich Gabriel S. , Seiffert Erik R. , Boyer Doug M. 
Published: March 2017

AbstractObjectiveOn the talus, the position and depth of the groove for theflexor hallucis longustendon have been used to infer phylogenetic affinities and positional behaviors of fossil primates. This study quantifies aspects of theflexor hallucis longusgroove (FHLG) to test if: (1) a lateral FHLG is a derived strepsirrhine feature, (2) a lateral FHLG reflects inverted and abducted foot postures, and (3) a deeper FHLG indicates a larger muscle.MethodsWe used linear measurements of microCT‐generated models from a sample of euarchontans (n = 378 specimens, 125 species) to quantify FHLG position and depth. Data are analyzed with ANOVA, Ordinary and Phylogenetic Generalized Least Squares, and Bayesian Ancestral State Reconstruction (ASR).ResultsExtant strepsirrhines, adapiforms, plesiadapiforms, dermopterans, andPtilocercusexhibit lateral FHLGs. Extant anthropoids, subfossil lemurs, andTupaiahave medial FHLGs. FHLGs of omomyiforms and basal fossil anthropoids are intermediate between those of strepsirrhines and extant anthropoids. FHLG position has few correlations with pedal inversion features. Relative FHLG depth is not significantly correlated with body mass. ASRs support a directional model for FHLG position and a random walk model for FHLG depth.ConclusionsThe prevalence of lateral FHLGs in many non‐euprimates suggests a lateral FHLG is not a derived strepsirrhine feature. The lack of correlations with pedal inversion features suggests a lateral FHLG is not a sufficient indicator of strepsirrhine‐like foot postures. Instead, a lateral FHLG may reduce the risk of tendon displacement in abducted foot postures on large diameter supports. A deep FHLG does not indicate a larger muscle, but likely reduces bowstringing during plantarflexion.
Horticultural activity predicts later localized limb status in a contemporary pre‐industrial population
Authors: Stieglitz Jonathan , Trumble Benjamin C. , Kaplan Hillard , Gurven Michael 
Published: March 2017

AbstractObjectivesModern humans may have gracile skeletons due to low physical activity levels and mechanical loading. Tests using pre‐historic skeletons are limited by the inability to assess behavior directly, while modern industrialized societies possess few socio‐ecological features typical of human evolutionary history. Among Tsimane forager‐horticulturalists, we test whether greater activity levels and, thus, increased loading earlier in life are associated with greater later‐life bone status and diminished age‐related bone loss.Materials and MethodsWe used quantitative ultrasonography to assess radial and tibial status among adults aged 20+ years (mean ± SD age = 49 ± 15; 52% female). We conducted systematic behavioral observations to assess earlier‐life activity patterns (mean time lag between behavioural observation and ultrasound = 12 years). For a subset of participants, physical activity was again measured later in life, via accelerometry, to determine whether earlier‐life time use is associated with later‐life activity levels. Anthropometric and demographic data were collected during medical exams.ResultsStructural decline with age is reduced for the tibia (female: −0.25 SDs/decade; male: 0.05 SDs/decade) versus radius (female: −0.56 SDs/decade; male: −0.20 SDs/decade), which is expected if greater loading mitigates bone loss. Time allocation to horticulture, but not hunting, positively predicts later‐life radial status (βHorticulture = 0.48, p = 0.01), whereas tibial status is not significantly predicted by subsistence or sedentary leisure participation.DiscussionPatterns of activity‐ and age‐related change in bone status indicate localized osteogenic responses to loading, and are generally consistent with the logic of bone functional adaptation. Nonmechanical factors related to subsistence lifestyle moderate the association between activity patterns and bone structure.
Accelerating, guiding, and sub‐wavelength trapping of neutral atoms with tailored optical vortices
Authors: Schulze D. , Thakur A. , Moskalenko A.S. , Berakdar J. 
Published: March 2017

Single neutral atom mechanics is controllable by focused, high‐intensity optical vortices. The intensity‐dependent, laser‐driven motion of the atom's active electrons subsumes to a net transfer of the orbital angular momentum of the light to the neutral atom. The ponderomotive force on these electrons translates so into an unbounded or a bounded radial drift of the atom depending on its initial kinetic energy, as set by the temperature. Appropriate combination of laser beams results in sub‐wavelength, dynamical radial traps for tweezing atoms controllably, an effect that can be exploited for atom guiding, structuring, and lithographic applications.
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para‐Selective C−H Borylation of (Hetero)Arenes by Cooperative Iridium/Aluminum Catalysis
Authors: Yang Lichen , Semba Kazuhiko , Nakao Yoshiaki 
Published: March 2017

Abstractpara‐Selective C−H borylation of benzamides and pyridines has been achieved by cooperative iridium/aluminum catalysis. A combination of iridium catalysts commonly employed for arene C−H borylation and bulky aluminum‐based Lewis acid catalysts provides an unprecedented strategy for controlling the regioselectivity of C−H borylation to give variously substituted (hetero)arylboronates, which are versatile synthetic intermediates for complex multi‐substituted aromatic compounds.
Insight into Ion Transfer through the Sub‐Nanometer Channels in Zeolitic Imidazolate Frameworks
Authors: Jiang Ze‐Yu , Liu Hai‐Ling , Ahmed Saud Asif , Hanif Sumaira , Ren Shi‐Bin , Xu Jing‐Juan , Chen Hong‐Yuan , Xia Xing‐Hua , Wang Kang 
Published: March 2017

AbstractA crack‐free sub‐nanometer composite structure for the study of ion transfer was constructed by in situ growth of ZIF‐90 [Zn(ICA)2, ICA=Imidazole‐2‐carboxaldehyde] on the tip of a glass nanopipette. The potential‐driven ion transfer through the sub‐nanometer channels in ZIF‐90 is strongly influenced by the pH of the solution. A rectification ratio over 500 is observed in 1 m KCl solution under alkaline conditions (pH 11.58), which is the highest value reported under such a high salt concentration. Fluorescence experiments show the super‐high rectification ratio under alkaline conditions results from the strong electrostatic interaction between ions and the sub‐nanometer channels of ZIF‐90. In addition to providing a general pathway for further study of mass‐transfer process through sub‐nanometer channels, the approach enable all kinds of metal–organic frameworks (MOFs) to be used as ionic permselectivity materials in nanopore‐based analysis.
Increased Synthetic Control—Gaining Access to Predicted Mg2Si5N8 and β‐Ca2Si5N8
Authors: Bielec Philipp , Schnick Wolfgang 
Published: March 2017

AbstractNitridosilicates represent an intriguing class of materials and are typically made up of highly condensed tetrahedral network structures. Alkaline‐earth nitridosilicates emerged as unique host materials for Eu2+ doped luminophores which found broad application in phosphor‐converted (pc)‐LEDs. In contrast to common strategies of preparing nitridosilicates by bottom‐up syntheses, we have now succeeded to post‐synthetically design nitridosilicates by ion exchange in metal halide melts. We describe the syntheses of hitherto unknown but predicted alkaline‐earth nitridosilicates, Mg2Si5N8 and β‐Ca2Si5N8. Both compounds were obtained by ion exchange starting from pre‐synthesized nitridosilicates. In situ investigations of the ion‐exchange process show that the Si–N network topology remains preserved. Therefore the reaction offers a significant increase of synthetic control with respect to classical bottom‐up syntheses.
Boosting the Performance of the Nickel Anode in the Oxygen Evolution Reaction by Simple Electrochemical Activation
Authors: Shinagawa Tatsuya , Ng Marcus Tze‐Kiat , Takanabe Kazuhiro 
Published: March 2017

AbstractThe development of cost‐effective and active water‐splitting electrocatalysts that work at mild pH is an essential step towards the realization of sustainable energy and material circulation in our society. Its success requires a drastic improvement in the kinetics of the anodic half‐reaction of the oxygen evolution reaction (OER), which determines the overall system efficiency to a large extent. A simple electrochemical protocol has been developed to activate Ni electrodes, by which a stable NiOOH phase was formed, which could weakly bind to alkali‐metal cations. The electrochemically activated (ECA) Ni electrode reached a current of 10 mA at <1.40 V vs. the reversible hydrogen electrode (RHE) at practical operation temperatures (>75 °C) and a mild pH of ca. 10 with excellent stability (>24 h), greatly surpassing that of the state‐of‐the‐art NiFeOx electrodes under analogous conditions. Water electrolysis was demonstrated with ECA‐Ni and NiMo, which required an iR‐free overall voltage of only 1.44 V to reach 10 mA cmgeo−2.
Boosting the Energy Density of Carbon‐Based Aqueous Supercapacitors by Optimizing the Surface Charge
Authors: Yu Minghao , Lin Dun , Feng Haobin , Zeng Yinxiang , Tong Yexiang , Lu Xihong 
Published: March 2017

AbstractThe voltage of carbon‐based aqueous supercapacitors is limited by the water splitting reaction occurring in one electrode, generally resulting in the promising but unused potential range of the other electrode. Exploiting this unused potential range provides the possibility for further boosting their energy density. An efficient surface charge control strategy was developed to remarkably enhance the energy density of multiscale porous carbon (MSPC) based aqueous symmetric supercapacitors (SSCs) by controllably tuning the operating potential range of MSPC electrodes. The operating voltage of the SSCs with neutral electrolyte was significantly expanded from 1.4 V to 1.8 V after simple adjustment, enabling the energy density of the optimized SSCs reached twice as much as the original. Such a facile strategy was also demonstrated for the aqueous SSCs with acidic and alkaline electrolytes, and is believed to bring insight in the design of aqueous supercapacitors.