A simple and efficient transition-metal/photocatalyst-free visible-light-driven one-pot three-component reaction between thianthrenium salts, carbon disulfide and amines under an air atmosphere for the preparation of biologically relevant S-aryl dithiocarbamates is developed. This methodology is robust and scalable, and exhibits a broad substrate scope and excellent functional group tolerance. Of note, a wide range of primary aliphatic amines bearing different groups are suitable for this strategy. The synthetic utility was further demonstrated by a two-step one-pot multi-component reaction and photo-flow decagram-scale synthesis. Preliminary mechanistic studies suggest that the association of the dithiocarbamate anion with thianthrenium salts formed an electron donor-acceptor complex, which upon excitation with visible light produced an aryl radical via single-electron transfer.

Alkyl boronic acids and their derivatives constitute vital building blocks in organic synthesis and are important motifs identified in medicinal chemistry. Herein, we present a phototriggered, CuCl2-catalyzed radical hydroalkylation and hydrosilylation of vinylboronic esters to alkylboronic esters. This approach exhibits mild reaction conditions, utilization of easily accessible reagents, and scalability up to a gram scale. Further synthetic transformations of the hydrosilylation products and mechanistic studies are also demonstrated.

An efficient nickel-catalyzed removal of alkene protection group under mild condition with high functional group tolerance through chain walking process has been established. Not only phenolic ethers, but also alcoholic ethers can be tolerated with the retention of stereocenter adjacent to hydroxyl group. The new reaction brings the homoallyl group into a start of new type of protecting group.

Cobalt sulfides (including CoS, CoS2, Co3S4, Co9S8 and nonstoichiometric Co1-xS) are deemed to a kind of novel anode material for lithium ion batteries due to their large specific capacities. However, cobalt sulfides suffer from poor cycling stability with the large volume expansion. In this work, we designed and synthesized a novel Co-metal organic frameworks (MOFs) material by using carbazolyl carboxylates ligand H4DCDC. The Co1-xS nanoparticles embedded in N-doped carbon sheets (Co1-xS/NCS) composites are obtained via vulcanizing the Co-MOFs precursor. As a result, the Co1-xS/NCS exhibits outstanding cycling stability and maintains a high capacity of 796.3 mA h g(-1) at the current density of 200 mA g(-1) after 100 cycles. The N-doped carbon sheets can not only enhance the conductivity of materials but also buffer the volume expansion during charge-discharge process.

The efficient, one-pot access to the transamidation of 8-aminoquinoline (8-AQ), notorious for its harsh removal conditions, has been widely employed as an auxiliary in C–H functionalization reactions due to its strong directing ability. In this study, the facile and mild Boc protection of the corresponding 8-AQ amide was critical to activate the amide C(acyl)–N bond by twisting its geometry to lower the amidic resonance energy. Both aryl and alkyl amines proceeded transamidation in one-pot, user-friendly conditions with excellent yields.

Described is a cross-electrophilic, deaminative coupling strategy harnessing Katritzky salts as a new species of electrophile in Ni/photoredox dual catalytic reductive cross-coupling reactions. Distinguishing features of this arylation protocol include its mild reaction conditions, high chemoselectivity, and adaptability to a variety of complex substrates [i.e., pyridinium salts derived from amines and partners derived from (hetero)aryl bromides].

A redox-neutral alkyl Petasis reaction has been developed that proceeds via photoredox catalysis. A diverse set of primary, secondary, and tertiary alkyltrifluoroborates participate effectively in this reaction through a single-electron transfer mechanism, in contrast to the traditional two-electron Petasis reaction, which accommodates only unsaturated boronic acids. This protocol is ideal to diversify benzyl-type and glyoxalate-derived aldehydes, anilines, and alkyltrifluoroborates toward the rapid assembly of libraries of higher molecular complexity important in pharmaceutical and agrochemical settings.

New carbon-carbon bond formation reactions expand our horizon of retrosynthetic analysis for the synthesis of complex organic molecules. Although many methods are now available for the formation of C(sp(2))-C(sp(3)) and C(sp(3))-C(sp(3)) bonds via transition metal-catalyzed cross-coupling of alkyl organometallic reagents, direct use of readily available olefins in a formal fashion of hydrocarbonation to make C(sp(2))-C(sp(3)) and C(sp(3))-C(sp(3)) bonds remains to be developed. Here we report the discovery of a general process for the intermolecular reductive coupling of unactivated olefins with alkyl or aryl electrophiles under the promotion of a simple nickel catalyst system. This new reaction presents a conceptually unique and practical strategy for the construction of C(sp(2))-C(sp(3)) and C(sp(3))-C(sp(3)) bonds without using any organometallic reagent. The reductive olefin hydrocarbonation also exhibits excellent compatibility with varieties of synthetically important functional groups and therefore, provides a straightforward approach for modification of complex organic molecules containing olefin groups.

A sustainable procedure for the synthesis of N-heteroaryl amides directly from oxidative amidation of aldehydes catalyzed by heteropolyanion-based ionic liquids under microwave-promoted conditions has been reported. The transformation has proven to tolerate a wide range of aldehydes and amino heterocycles with different functional groups. Moderate to excellent yields, solvent-free media, operational simplicity and reusability of catalysts are the main highlights. Furthermore, the proposed N-directing dual-catalysis mechanistic pathway was briefly investigated in this report.

An efficient, eco-friendly and sustainable method for the tandem oxidative amidation of alcohols with amines has been reported. Using heteropolyanion-based ionic liquids as the catalyst and tert-butyl hydroperoxide as the oxidant, this amidation reaction is operationally straightforward and provides a series of primary, secondary and tertiary amides derivatives in moderate to good yields. Solvent-free media, microwave-promoted conditions and reusability of catalysts are the main highlights. Further, the proposed bifunctional catalysis mechanistic pathway has been briefly investigated in this report.

An efficient nickel catalyst system for the direct ortho C-H alkynylation of the amides has been successfully developed with the directing assistance of 8-aminoquinoline. It was found that the flexible bis(2-dimethylaminoethyl) ether (BDMAE) ligand was critical to achieve the optimized reactivity. This protocol showed good tolerance toward not only a wide range of (hetero)aryl amides but also the rarely studied α,β-unsaturated alkenyl amide. The directing amide group could be easily transformed to aldehyde or ester in high yields. Meanwhile, the removable TIPS substituent on the resultant aryl/alkenyl alkynes could be further converted to an aryl moiety through a Sila-Sonogashira coupling reaction. This Ni-catalyzed alkynylation procedure provides an alternative approach to construct a C(sp(2))-C(sp) bond.

A novel method for the synthesis of non-natural L- and D-amino acids by a Ni-catalyzed reductive cross-coupling reaction is described. This strategy enables the racemization-free cross-coupling of serine/homoserine- derived iodides with aryl/acyl/alkyl halides. It provides convenient access to varieties of enantiopure and functionalized amino acids, which are important building blocks in bioactive compounds and pharmaceuticals.

A copper-catalyzed Suzuki-Miyaura coupling of benzyl halides with arylboronates is described. Varieties of primary benzyl halides as well as more challenging secondary benzyl halides with β hydrogens or steric hindrance could be successfully converted into the corresponding products. Thus it provides access to diarylmethanes, diarylethanes and triarylmethanes.

Palladium- and nickel-catalyzed cross-coupling recations of unactivated alkyl bromides with diboron reagents have been developed as practical methods for the synthesis of primary and secondary alkylboronic esters. These reactions extend the concept and utility of Pd- and Ni-catalyzed cross-coupling of aliphatic electrophiles. They also show different substrate selectivity and ligand dependence as compared to the recently reported Cu-catalyzed borylation reaction.

A Pd-catalyzed coupling reaction of ArBr/ArCl/ArOTf with sodium thiosulfate takes place in presence of Cs2CO3 at 80°C. The reaction mixture is directly treated with Zn/HCl to afford aryl thiols in good to excellent yields.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Although nitrogen-containing group-directed cyclopalladation reactions have been well-known, Pd(II) insertion into C-H bonds promoted by coordination of an oxygen-only group to the palladium remains rather rare. In the present study, the first cyclopalladation complex formed from a simple phenol ester was characterized by X-ray crystallography. A promising protocol for the ortho C-H activation/aryl-aryl coupling of phenol esters that was not sensitive to moisture or air was then established. The utility of the reaction was demonstrated for the synthesis of useful phenol derivatives.

Resin-bound organic ionic bases (RBOIBs) were developed in which tetraalkyl-ammonium or phosphonium cations are covalently attached to solid resins. The application tests showed that the performance of the tetraalkyl-ammonium-type RBOIBs is slightly better than that of the corresponding Cs salts in Cu-catalyzed C-N cross-couplings, while the tetraalkylphosphonium-type RBOIBs are significantly better than all the inorganic bases. With these newly developed RBOIBs, room-temperature Cu-catalyzed C-N coupling with various nonactivated aryl iodides and even aryl bromides can be readily accomplished. Moreover, RBOIBs can be easily recycled and reused for a number of times without much drop of activity. The good performances of RBOIBs are proposed to arise from the relatively weak binding forces between the cationic polymer backbone and basic anions, as opposed to the strong metal-anion interactions in the inorganic bases. Further applications of RBOIBs in Ni-catalyzed Suzuki-type couplings at room temperature, Cu-catalyzed C-N couplings at -30 °C, a Pd-catalyzed Heck reaction at 60 °C, and Cu-catalyzed C-S couplings at room temperature demonstrate that RBOIBs are generally applicable bases with improved performance for many other types of organic transformations.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.