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Herein, we describe a stereoselective Ni‐catalyzed N‐glycosylation of glycals. The reaction is enabled by addition of an in situ generated nickel hydride across an olefin prior to C−N bond‐formation. Stereodivergence can be accomplished on kinetic or thermodynamic grounds, thus giving access to either α‐ or β‐N‐glycosides with equal ease. The protocol is distinguished by its operational simplicity, generality and exquisite selectivity, thus offering a new gateway to expedite the synthesis of N‐glycosides. [ABSTRACT FROM AUTHOR]

Herein, we disclose a new strategy that rapidly and reliably incorporates bromine atoms at distal, secondary C(sp3)−H sites in aliphatic amines with an excellent and predictable site‐selectivity pattern. The resulting halogenated building blocks serve as versatile linchpins to enable a series of carbon‐carbon and carbon‐heteroatom bond‐formations at remote C(sp3) sites, thus offering a new modular and unified platform that expediates the access to advanced sp3 architectures possessing valuable nitrogen‐containing saturated heterocycles of interest in medicinal chemistry settings. [ABSTRACT FROM AUTHOR]

This study reports the extraction of phenolic compound from shells and kernels of the Raphia farinifera fruit and the biological activities of the extract. A face-centered composite design was established to optimize the extraction conditions: ethanol/water ratio (0-100%), solvent/powder ratio (10-30 mL/g), and extraction time (90-180 min). Subsequently, the extracts obtained under the optimal conditions were used for the evaluation of the radical scavenging capacity, the capacity to chelate ferric ions, and the antimicrobial and anti-inflammatory activities. The optimal extraction conditions for the shells are an extraction time of 134.24 min, 65% ethanol in water, and a solvent/substrate ratio of 21.16 mL/g, and for the kernel, an extraction time of 180 min, 94.3% ethanol in water, and a solvent/substrate ratio of 18.6 mL/g. In these conditions, the phenolic compounds were 95.36 mg EAG/L for the shell extract and 139.72 mg EAG/L for the kernel extract. The antioxidant activity revealed that the half-maximal inhibitory concentrations (IC50) of the kernel extracts are 22.32 μg/mL and 55.73 μ g/mL for the shells. A reducing activity of Fe 3+ ions with an activity of 308.39 μg EAA/mg for the kernel extracts and 293 μg EAA/mg for the shells was observed. B. cereus was the most sensitive microorganism with a minimum inhibitory concentration (MIC) equal to the minimum bactericidal concentration (MBC) with a value of 156.25 ppm for the kernel extract while the shell extract showed MIC of 625 ppm and MBC of 2500 ppm. The IC50 values for the denaturation of proteins by extracts of shells and kernels are 0.76 μg/mL and 0.56 μ g/mL, respectively. Membrane stabilization revealed IC50 values of 1054.54 μ g/mL and 1339 μ g/mL for the shell and kernel extracts, respectively. This work has shown the potential of Raphia farinifera extracts for the food industry and cosmetics. [ABSTRACT FROM AUTHOR]

Unactivated olefins rank amongst the most important feedstocks in organic synthesis. Their availability makes them particularly useful synthons for subsequent functionalization, particularly in a catalytic manner. Driven by the popularity ascribed by nickel catalysis as a new tool to rapidly forge molecular architectures via one‐or two‐electron manifolds, the recent years have witnessed significant advances in Ni‐catalyzed olefin difunctionalization. While 1,2‐difunctionalization or remote functionalization via "chain‐walk" have become mature disciplines for repurposing the potential of olefins as building blocks, it was only recently that extensions of this chemistry to 1,1‐difunctionalization have been possible. This review summarizes the recent advances in Ni‐catalyzed olefin 1,1‐difunctionalization, holding considerable promise as a new powerful strategy for our ever‐growing synthetic repertoire. [ABSTRACT FROM AUTHOR]

An α‐difluoroalkylation of benzyl amines with trifluoromethylarenes is disclosed herein. This protocol is characterized by its operational simplicity, excellent chemoselectivity and broad scope—even with advanced synthetic intermediates—, thus offering a new entry point to medicinally‐relevant α‐difluoroalkylated amines from simple, yet readily accessible, precursors. [ABSTRACT FROM AUTHOR]

A dual photocatalytic sulfonylation‐arylation of electron‐rich alkenes is described. By combining sulfinate salts, (hetero)‐aryl‐bromides and 2,3‐dihydrofuran under Ru and Ni dual catalysis, over 35 examples of aryl‐sulfonylated scaffolds could be obtained in good to excellent yields, under mild reaction conditions and high diastereoselectivity. [ABSTRACT FROM AUTHOR]

Herein, we describe a catalytic intramolecular decarboxylative/desulfonylative sp3 allylation triggered by sulfinate salts under light irradiation. The reaction is likely enabled by a non‐classical, radical‐polar crossover mechanism, allowing rapid and reliable access to valuable allyl architectures from readily accessible precursors. The protocol is characterized by its operational simplicity and scalability, employing abundant, commercially available catalysts. [ABSTRACT FROM AUTHOR]

Herein, we report a Cu‐mediated trifluoromethylation of carbonyl‐type compounds and unactivated olefins enabled by visible‐light irradiation via σ C(sp3)−C bond‐functionalization. The reaction is distinguished by its modularity, mild conditions and wide scope—even in the context of late‐stage functionalization—thus offering a complementary approach en route to valuable C(sp3)−CF3 architectures from easily accessible precursors. [ABSTRACT FROM AUTHOR]

Herein, we describe the development of a copper‐catalyzed C(sp3)‐amination of proaromatic dihydroquinazolinones derived from ketones. The reaction is enabled by the intermediacy of open‐shell species arising from homolytic C−C bond‐cleavage driven by aromatization. The protocol is characterized by its operational simplicity and generality, including chemical diversification of advanced intermediates. [ABSTRACT FROM AUTHOR]

A nickel‐catalyzed site‐selective intermolecular amidation of saturated C(sp3)−H bonds is reported. This mild protocol exhibits a predictable reactivity pattern to incorporate amide functions at C(sp3)−H sites adjacent to nitrogen and oxygen atoms in either cyclic or acyclic frameworks, thus offering a complementary reactivity profile to existing oxidative‐type processes or metal‐catalyzed C(sp3)−N bond‐forming reactions operating via two‐electron manifolds. [ABSTRACT FROM AUTHOR]

Bumble bees are key pollinators with some species reared in captivity at a commercial scale, but with significant evidence of population declines and with alarming predictions of substantial impacts under climate change scenarios. While studies on the thermal biology of temperate bumble bees are still limited, they are entirely absent from the tropics where the effects of climate change are expected to be greater. Herein, we test whether bees' thermal tolerance decreases with elevation and whether the stable optimal conditions used in laboratory‐reared colonies reduces their thermal tolerance. We assessed changes in the lower (CTMin) and upper (CTMax) critical thermal limits of four species at two elevations (2600 and 3600 m) in the Colombian Andes, examined the effect of body size, and evaluated the thermal tolerance of wild‐caught and laboratory‐reared individuals of Bombus pauloensis. We also compiled information on bumble bees' thermal limits and assessed potential predictors for broadscale patterns of variation. We found that CTMin decreased with increasing elevation, while CTMax was similar between elevations. CTMax was slightly higher (0.84°C) in laboratory‐reared than in wild‐caught bees while CTMin was similar, and CTMin decreased with increasing body size while CTMax did not. Latitude is a good predictor for CTMin while annual mean temperature, maximum and minimum temperatures of the warmest and coldest months are good predictors for both CTMin and CTMax. The stronger response in CTMin with increasing elevation, and similar CTMax, supports Brett's heat‐invariant hypothesis, which has been documented in other taxa. Andean bumble bees appear to be about as heat tolerant as those from temperate areas, suggesting that other aspects besides temperature (e.g., water balance) might be more determinant environmental factors for these species. Laboratory‐reared colonies are adequate surrogates for addressing questions on thermal tolerance and global warming impacts. [ABSTRACT FROM AUTHOR]

A catalytic 1,1‐difunctionalization of unactivated olefins en route to sp3bis‐organometallic B,B(Si)‐reagents is described. The protocol is characterized by exceptional reaction rates, mild conditions, wide scope, and exquisite selectivity pattern, constituting a new platform to access sp3bis‐organometallics. [ABSTRACT FROM AUTHOR]

A modular, site‐selective 1,2‐dicarbofunctionalization of vinyl boronates with organic halides through dual catalysis is described. This reaction proceeds under mild conditions and is characterized by excellent chemo‐ and regioselectivity. It thus represents a complementary new technique for preparing densely functionalized alkyl boron architectures from simple and accessible precursors. [ABSTRACT FROM AUTHOR]

Nickel catalysts have recently played an important role for rapidly and reliably converting feedstock chemicals into valuable compounds of interest for both pharmaceutical and academic laboratories. Herein, we summarize the recent advances on the ability of nickel catalysts to trigger olefin isomerization via "chain‐walking", causing a displacement of the nickel catalyst throughout the alkyl chain while opening up new grounds for forging C−C and C‐heteroatom linkages at remote, yet unfunctionalized, sp3 C−H bonds. [ABSTRACT FROM AUTHOR]

A base‐catalyzed reaction that enables stereoselective 1,1‐silaboration of terminal alkynes is described. This method not only offers a new strategy to functionalize simple and readily accessible alkynes beyond 1,2‐difunctionalization, but also provides an unconventional atom‐ and step‐economical approach to rapidly and reliably access versatile geminal silylboranes in the absence of transition metals and with exquisite stereoselectivity. [ABSTRACT FROM AUTHOR]

A photoinduced carboxylation of alkyl halides with CO2 at remote sp3 C−H sites enabled by the merger of photoredox and Ni catalysis is described. This protocol features a predictable reactivity and site selectivity that can be modulated by the ligand backbone. Preliminary studies reinforce a rationale based on a dynamic displacement of the catalyst throughout the alkyl side chain. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Driven by the inherent synthetic potential of CO2 as an abundant, inexpensive and renewable C1 chemical feedstock, the recent years have witnessed renewed interest in devising catalytic CO2 fixations into organic matter. Although the formation of C−C bonds via catalytic CO2 fixation remained rather limited for a long period of time, a close look into the recent literature data indicates that catalytic carboxylation reactions have entered a new era of exponential growth, evolving into a mature discipline that allows for streamlining the synthesis of carboxylic acids, building blocks of utmost relevance in industrial endeavors. These strategies have generally proven broadly applicability and convenient to perform. However, substantial challenges still need to be addressed reinforcing the need to cover metal‐catalyzed carboxylation area in a conceptual and concise manner, delineating the underlying new principles that are slowly emerging in this vibrant area of expertise. With a certain lag time, metal‐catalyzed carboxylation reactions of organic matter with CO2 as C1 feedstock have entered a new era of exponential growth. These C−C bond formations are characterized by their mild conditions and excellent chemo‐ and site selectivity for a wide range of coupling partners, holding promise to streamline synthetic sequences en route to carboxylic acids. [ABSTRACT FROM AUTHOR]

The natural occurrence of amides and their unique roles in synthetic materials and biologically active compounds make amide synthesis one of the most routinely performed reactions in organic chemistry. Despite the advances achieved, there is a growing need for the design of new catalytic technologies to complement existing amide bond‐forming reactions, which are often based on the formation of carbon–nitrogen bonds. Recent years have witnessed the development of a new disconnection approach to forging amides by means of metal‐catalyzed carbon–carbon bond‐forming reactions. This microreview highlights the most recent developments in the use of isocyanates in metal‐catalyzed amidations that take place according to this design principle. With the aim of illustrating the prospective impact of the use of isocyanates as amide synthons, this review highlights the advantages and drawbacks of the existing methods and describes the mechanistic implications when appropriate. [ABSTRACT FROM AUTHOR]

Abstract: A nickel‐catalyzed reductive arylation of ambiphilic α‐bromoalkyl boronic esters with aryl halides is described. This platform provides an unrecognized opportunity to promote the catalytic umpolung reactivity of ambiphilic reagents with aryl halides, thus unlocking a new cross‐coupling strategy that complements existing methods for the preparation of densely functionalized alkyl‐substituted organometallic reagents from simple and readily accessible precursors. [ABSTRACT FROM AUTHOR]

A redox-neutral intermolecular dicarbofunctionalization of styrenes with CO2 at atmospheric pressure and carbon-centered radicals is described. This mild protocol results in multiple C−C bond-forming reactions from simple precursors in the absence of stoichiometric reductants, thus exploiting a previously unrecognized opportunity that complements existing catalytic carboxylation events. [ABSTRACT FROM AUTHOR]

A switchable site-selective catalytic carboxylation of allylic alcohols has been developed in which CO2 is used with dual roles, both facilitating C−OH cleavage and as a C1 source. This protocol is characterized by its mild reaction conditions, absence of stoichiometric amounts of organometallic reagents, broad scope, and exquisite regiodivergency which can be modulated by the type of ligand employed. [ABSTRACT FROM AUTHOR]

A switchable site-selective catalytic carboxylation of allylic alcohols has been developed in which CO2 is used with dual roles, both facilitating C−OH cleavage and as a C1 source. This protocol is characterized by its mild reaction conditions, absence of stoichiometric amounts of organometallic reagents, broad scope, and exquisite regiodivergency which can be modulated by the type of ligand employed. [ABSTRACT FROM AUTHOR]

In this Communication one of the affiliations for the author Prof. Ruben Martin was inadvertently omitted. Corrigendum: Nickel-Catalyzed Site-Selective Intermolecular C(sp3)-H Amidation Full and complete affiliations for this author are given below: Prof. Ruben Martin Institute of Chemical Research of Catalonia (ICIQ) The Barcelona Institute of Science and Technology Av. Països Catalans 16, 43007 Tarragona (Spain) and Catalan Institution for Research and Advanced Studies (ICREA) Passeig Lluïs Companys, 23, 08010 Barcelona (Spain). [Extracted from the article]

A user-friendly, nickel-catalyzed reductive amidation of unactivated primary, secondary, and tertiary alkyl bromides with isocyanates is described. This catalytic strategy offers an efficient synthesis of a wide range of aliphatic amides under mild conditions and with an excellent chemoselectivity profile while avoiding the use of stoichiometric and sensitive organometallic reagents. [ABSTRACT FROM AUTHOR]

A user-friendly Ni-catalyzed reductive carboxylation of benzylic C−N bonds with CO2 is described. This procedure outperforms state-of-the-art techniques for the carboxylation of benzyl electrophiles by avoiding commonly observed parasitic pathways, such as homodimerization or β-hydride elimination, thus leading to new knowledge in cross-electrophile reactions. [ABSTRACT FROM AUTHOR]

A user-friendly Ni-catalyzed reductive carboxylation of benzylic C−N bonds with CO2 is described. This procedure outperforms state-of-the-art techniques for the carboxylation of benzyl electrophiles by avoiding commonly observed parasitic pathways, such as homodimerization or β-hydride elimination, thus leading to new knowledge in cross-electrophile reactions. [ABSTRACT FROM AUTHOR]

The first catalytic intermolecular proximal C1C2 cleavage of benzocyclobutenones (BCB) without prior carbonyl activation or employing noble metals has been developed. This protocol operates at room temperature and is characterized by an exquisite chemo-, regio- and diastereoselectivity profile, constituting a unique platform for preparing an array of elusive carbocyclic skeletons. [ABSTRACT FROM AUTHOR]

We report the first enantioselective CC bond formation through CO bond cleavage using aryl ester counterparts. This method is characterized by its wide substrate scope and results in the formation of quaternary stereogenic centers with high yields and asymmetric induction. [ABSTRACT FROM AUTHOR]

Erneut im Rampenlicht steht die Fähigkeit von Nickelkomplexen zur Spaltung starker σ ‐ Bindungen nach einer jüngsten Arbeit, in der die Decarbonylierung von Diarylketonen beschrieben wurde. Diese Umwandlung verläuft unter Spaltung zweier starker C ‐ C(O) ‐ Bindungen und benötigt kein Edelmetall. Die Ergebnisse bekräftigen das Potential der Decarbonylierung als Methode zur Knüpfung von C ‐ C ‐ Bindungen. [ABSTRACT FROM AUTHOR]

The ability of nickel to cleave strong σ‐bonds is again in the spotlight after a recent report that demonstrates the feasibility of using nickel complexes to promote decarbonylation of diaryl ketones. This transformation involves the cleavage of two strong C−C(O) bonds and avoids the use of noble metals, hence reinforcing the potential of decarbonylation as a technique for forging C−C bonds. [ABSTRACT FROM AUTHOR]

Pheochromocytomas and paragangliomas (PPGLs) are catecholamine-producing chromaffin cell tumors with diverse phenotypic features reflecting mutations in numerous genes, including MYC-associated factor X ( MAX). To explore whether phenotypic differences among PPGLs reflect a MAX-mediated mechanism and opposing influences of hypoxia-inducible factor (HIF)s HIF2α and HIF1α, we combined observational investigations in PPGLs and gene-manipulation studies in two pheochromocytoma cell lines. Among PPGLs from 140 patients, tumors due to MAX mutations were characterized by gene expression profiles and intermediate phenotypic features that distinguished these tumors from other PPGLs, all of which fell into two expression clusters: one cluster with low expression of HIF2α and mature phenotypic features and the other with high expression of HIF2α and immature phenotypic features due to mutations stabilizing HIFs. Max-mutated tumors distributed to a distinct subcluster of the former group. In cell lines lacking Max, re-expression of the gene resulted in maturation of phenotypic features and decreased cell cycle progression. In cell lines lacking Hif2α, overexpression of the gene led to immature phenotypic features, failure of dexamethasone to induce differentiation and increased proliferation. HIF1α had opposing actions to HIF2α in both cell lines, supporting evolving evidence of their differential actions on tumorigenic processes via a MYC/MAX-related pathway. Requirement of a fully functional MYC/MAX complex to facilitate differentiation explains the intermediate phenotypic features in tumors due to MAX mutations. Overexpression of HIF2α in chromaffin cell tumors due to mutations affecting HIF stabilization explains their proliferative features and why the tumors fail to differentiate even when exposed locally to adrenal steroids. [ABSTRACT FROM AUTHOR]

A tandem C(sp2)H and C(sp3)H functionalization/CO bond formation catalyzed by iodine(III) reagents generated in situ has been developed. The method shows wide scope under mild conditions and exhibits an unprecedented selectivity profile that can be switched depending on the catalyst employed. [ABSTRACT FROM AUTHOR]

Metal-catalyzed reductive coupling reactions of aryl halides and (pseudo)halides with carbonyl-type compounds have undergone an impressive development within the last years. These methodologies have shown to be a powerful alternate strategy, practicality aside, to the use of stoichiometric, well-defined, and, in some cases, air-sensitive organometallic species. In this Minireview, the recent findings in this field are summarized, with particular emphasis on the mechanistic interpretation of the results and future aspects of this area of expertise. [ABSTRACT FROM AUTHOR]

Aktivierung à la carte: Mit aromatischen Estern als Kupplungspartner und Nickel als Katalysator gelang die direkte Arylierung von Heteroarenen (HetAr; siehe Schema; Z=O, S). Der entscheidende Schritt ist eine unkonventionelle, neuartige Ni ‐ katalysierte decarbonylierende Kupplung. [ABSTRACT FROM AUTHOR]

Activation à la carte: The direct arylation of heteroarenes was accomplished by employing aromatic esters as effective coupling partners under nickel catalysis (see scheme; Z=O, S). The key process implies an unconventional and unprecedent Ni‐catalyzed decarbonylative coupling utilizing cost‐efficient nickel catalysts. [ABSTRACT FROM AUTHOR]

A carboacylation of iodoalkyl olefins with carbon monoxide provides 5- to 7-membered cyclic compounds under mild reaction conditions. [ABSTRACT FROM AUTHOR]

Der mächtige Drache …… hier das Sinnbild eines Nickel ‐ Katalysators, greift die Ausgangsmaterialien (Isocyanate und nichtaktivierte Alkylbromide) mit seinen Klauen und verschmilzt sie durch seinen feurigen Atem zu aliphatischen Amiden. R. Martin und E. Serrano zeigen in der Zuschrift auf S. 11373 ff., dass diese vielseitige Reaktion schon unter milden Bedingungen hoch chemoselektiv abläuft. Die Ouroboros ‐ Pose des Drachen verweist auf den abgeschlossenen Katalysezyklus und die Regenerierung des Ni ‐ Katalysators. [ABSTRACT FROM AUTHOR]

The back cover of the journal "Angewandte Chemie International Edition" is presented.