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Tricks of the trade: Because intramolecular Cu‐catalyzed access to bicyclo[4.2.0]octanes is not feasible, an oxygen bridge was introduced to facilitate the [2+2] photocycloaddition. Starting from compounds similar to 1, products such as 2 could be obtained enantioselectiviely in three steps after ring‐opening metathesis (see scheme). [ABSTRACT FROM AUTHOR]

Abstract: The enthalpies of dilution have been measured for aqueous Li2B4O7 solutions from 0.0212 to 2.1530molkg−1 at 298.15K. The relative apparent molar enthalpies, L ϕ , and relative partial molar enthalpies of the solvent and solute, and were calculated. The thermodynamic properties of the complex aqueous solutions were represented with a modified Pitzer ion-interaction model. [Copyright &y& Elsevier]

A method is proposed for the extraction and individual separation of trivalent gallium, indium and thallium with sec-octylphenoxy acetic acid (CA-12), sec-nonylphenoxy acetic acid (CA-100) and naphthenic acid (NA) from chloride media. The distribution equilibria of gallium (III), indium (III), thallium (III) and thallium (I) between carboxylic acids (CA-12, CA-100 and NA) dissolved in kerosene and acidic aqueous chloride media has been investigated as a function of the concentration of extractants and the concentration of hydrogen ion in aqueous phase. A possible mechanism of the extraction is discussed. The method permits rapid and precise individual separation of gallium (III), indium (III) and thallium (III), and is applicable to the analysis of alloy samples. [Copyright &y& Elsevier]

Comprehensive Summary Chiral 1,3‐substituted fragments are ubiquitous in pharmaceutical molecules and natural products, prompting the development of numerous methods to access these structures. Nonetheless, devising synthetic routes for complex chiral architectures in practical applications typically demands years of expertise. Herein, we developed a nickel‐catalyzed enantioselective migratory arylboration reaction of allylboronic esters using a chiral 1,2‐diamine ligand, yielding a range of chiral 1,3‐bis(boronates) with high enantioselectivity. The protocol is characterized by its use of commercially available substrates, mild reaction conditions, user‐friendly procedures, and a broad substrate compatibility. Moreover, we demonstrate the practicality and application potential of this reaction by synthesizing several key drug intermediates. [ABSTRACT FROM AUTHOR]

Abstract: Carbon dioxide is a ubiquitous and inexpensive one‐carbon source for chemical synthesis, and the efficient incorporation of CO2 into organic molecules is of widespread research interest both for economic and ecological reasons. The methodologies to employ carbon dioxide as a single‐carbon unit to construct molecules relevant for agrochemical and pharmaceutical research include many elegant approaches, including asymmetric transformations. Even though remarkable achievements have been made in the field of light‐driven catalysis, especially photoredox catalysis, homogeneous light‐driven catalytic carboxylation by employing CO2 as the key reagent has only become a subject of increasing attention in recent years. Therefore, this concise review will discuss the latest advances in this research area. [ABSTRACT FROM AUTHOR]

Abstract: Carbon dioxide is a ubiquitous and inexpensive one‐carbon source for chemical synthesis, and the efficient incorporation of CO2 into organic molecules is of widespread research interest both for economic and ecological reasons. The methodologies to employ carbon dioxide as a single‐carbon unit to construct molecules relevant for agrochemical and pharmaceutical research include many elegant approaches, including asymmetric transformations. Even though remarkable achievements have been made in the field of light‐driven catalysis, especially photoredox catalysis, homogeneous light‐driven catalytic carboxylation by employing CO2 as the key reagent has only become a subject of increasing attention in recent years. Therefore, this concise review will discuss the latest advances in this research area. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Multi‐substituted cyclohexanes play a crucial role as scaffolds in bioactive compounds. While significant progress has been made in synthesizing substituted cyclohexanes, methods for the stereoselective assembly of 1,3‐disubstituted cyclohexanes remain scarce. This study presents a novel approach involving nickel catalysis to achieve stereoselective carboboration of 1,4‐cyclohexadiene. This innovative process allows for the simultaneous introduction of a boron group and an aryl or an alkyl fragment into the 1,4‐cyclohexadiene framework under mild conditions, with exclusive regioselectivity and excellent cis configuration. The resulting products feature a double carbon bond and the incorporation of the boron group, offering significant potential for subsequent transformations and downstream applications. [ABSTRACT FROM AUTHOR]

We report herein a modular catalytic method for the efficient enantioselective synthesis of chiral allylboronates from abundant feedstock chemicals through an asymmetric 1,1-difunctionalization of alkenes. This protocol is distinguished by its use of an inexpensive chiral catalyst, mild and convenient reaction conditions, wide substrate scope, scalability and practicality. The utility of this method is demonstrated by the rapid synthesis of key intermediates of complex drug molecules. Mechanistic studies reveal that β-H elimination is a highly regioselective step and the reversible homolysis and convergance to the lower energy pre-reductive elimination intermediate is the enantio-determining step., (© 2022 Wiley-VCH GmbH.)

While chiral allylic organophosphorus compounds are widely utilized in asymmetric catalysis and for accessing bioactive molecules, their synthetic methods are still very limited. We report the development of asymmetric nickel/Brønsted acid dual-catalyzed hydrophosphinylation of 1,3-dienes with phosphine oxides. This reaction is characterized by an inexpensive chiral catalyst, broad substrate scope, and high regio- and enantioselectivity. This study allows the construction of chiral allylic phosphine oxides in a highly economic and efficient manner. Preliminary mechanistic investigations suggest that the 1,3-diene insertion into the chiral Ni-H species is a highly regioselective process and the formation of the chiral C-P bond is an irreversible step., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

This report widens the repertoire of emerging Pd I catalysis to carbon-heteroatom, that is, C-S bond formation. While Pd 0 -catalyzed protocols may suffer from the formation of poisonous sulfide-bound off-cycle intermediates and lack of selectivity, the mechanistically diverse Pd I catalysis concept circumvents these challenges and allows for C-S bond formation (S-aryl and S-alkyl) of a wide range of aryl halides. Site-selective thiolations of C-Br sites in the presence of C-Cl and C-OTf were achieved in a general and a priori predictable fashion. Computational, spectroscopic, X-ray, and reactivity data support dinuclear Pd I catalysis to be operative. Contrary to air-sensitive Pd 0 , the active Pd I species was easily recovered in the open atmosphere and subjected to multiple rounds of recycling., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

While nickel catalysts have previously been shown to activate even the least reactive Csp 2 -O bonds, i.e. aryl ethers, in the context of C-C bond formation, little is known about the reactivity limits and molecular requirements for the introduction of valuable functional groups under homogeneous nickel catalysis. We identified that due to the high reactivity of Ni-catalysts, they are also prone to react with existing or installed functional groups, which ultimately causes catalyst deactivation. The scope of the Ni-catalyzed coupling protocol will therefore be dictated by the reactivity of the functional groups towards the catalyst. Herein, we showed that the application of computational tools allowed the identification of matching functional groups in terms of suitable leaving groups and tolerated functional groups. This allowed for the development of the first efficient protocol to trifluoromethylthiolate Csp 2 -O bonds, giving the mild and operationally simple C-SCF 3 coupling of a range of aryl, vinyl triflates and nonaflates. The novel methodology was also applied to biologically active and pharmaceutical relevant targets, showcasing its robustness and wide applicability.

While palladium catalysis is ubiquitous in modern chemical research, the recovery of the active transition-metal complex under routine laboratory applications is frequently challenging. Described herein is the concept of alternative cross-coupling cycles with a more robust (air-, moisture-, and thermally-stable) dinuclear Pd(I) complex, thus avoiding the handling of sensitive Pd(0) species or ligands. Highly efficient C-SCF3 coupling of a range of aryl iodides and bromides was achieved, and the recovery of the Pd(I) complex was accomplished via simple open-atmosphere column chromatography. Kinetic and computational data support the feasibility of dinuclear Pd(I) catalysis. A novel SCF3-bridged Pd(I) dimer was isolated, characterized by X-ray crystallography, and verified to be a competent catalytic intermediate., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Palladium-catalyzed oxidative amination of unactivated alkyl olefins has been developed to produce linear (E)-allylimides with high regioselectivity. This highly efficient transformation of alkenes has been achieved by enhancing the reoxidation of palladium with the strong oxidant PhI(OPiv)(2). The present work also provides the first systematic analysis of the mechanism of the allylic C-H oxidative amination. It has been found that naphthoquinone (NQ) plays a vital role in promoting olefin coordination to the palladium catalyst: in the absence of NQ, the turnover-limiting step is olefin coordination to palladium catalyst; in the presence of NQ, the reaction involves a rapid equilibration to give a nitrogen-coordinated olefin-Pd(NQ) complex that undergoes turnover-limiting allylic C-H bond activation to generate a pi-allyl-Pd intermediate. This work provides valuable insights for further studies on the functionalization of unactivated olefins.