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A rhodium(iii)-catalyzed regioselective C2-alkenylation of indoles for the construction of α-CF3 substituted enamines has been developed, which utilizes CF3-imidoyl sulfoxonium ylides (TFISYs) as alkenylating agents for the first time.

Catalyzed by CuCl and DPEphos, various β-polyfluoroaryl boronates were obtained from styrenes and polyfluoroarenes via defluorinative arylboration. With the use of a chiral ligand, the first example of chiral version was realized.

Recent advances in the direct synthesis of trifluoromethyl-containing heterocycles from trifluoroacetimidoyl chlorides (TFAICs) and derivatives, including trifluoroacetimidohydrazides (TFAIHs) and CF3–imidoyl sulfoxonium ylides (TFISYs), are systematically summarized and discussed.

A one-pot 1,2-borocyclopropanation of aryl olefins for synthesizing β-boryl cyclopropanes was developed, catalyzed by the inexpensive copper catalyst. Various β-boryl cyclopropanes were produced in moderate to good yields.

We developed a palladium-catalyzed four-component carbonylative cyclization of alkenyl-tethered aryl iodides, trifluoroacetimidoyl chlorides and propargyl amines for the construction of carbonyl-bridged bisheterocycles.

A palladium-catalyzed cascade Heck-type cyclization and carbonylation reaction has been developed for the synthesis of functionalized thioesters.

A copper-catalyzed carbonylation process has been developed for the synthesis of diborylated cyclopropanes from both stable internal and terminal aryl olefins in moderate to good yields.

Herein, we reported an efficient and sustainable intramolecular electrochemical cyclization of N-allylcarboxamides for the synthesis of various halogenated oxazolines. This method was conducted in a simple undivided cell by employing lithium halogen salts as redox mediums and halogen sources. A wide range of oxazolines, including five- and six-membered heterocycles, iodine-, bromo-, and chloro-methyl oxazolines were constructed in moderate to good yields at room temperature. Notably, this electrochemical oxidative cyclization obviates the use of external oxidants.

A metal-free difunctional carbonylation procedure toward the synthesis of olefin sulfonyl methyl esters has been developed to give the desired olefin sulfonyl methyl esters in moderate to good yields.

A palladium-catalyzed Heck/carbonylative cyclization process has been explored for the synthesis of functionalized amides. By using nitroarenes as readily accessible nitrogen sources, a variety of amide products were obtained in moderate to excellent yields with good functional group compatibility. Furthermore, a late-stage modification of a natural molecule is also achieved by this protocol.

The electron pair of the heteroatom in heterocycles will coordinate with metal catalysts and decrease or even inhibit their catalytic activity consequently. In this work, a pincer ruthenium-catalyzed heterocycle compatible alkoxycarbonylation of alkyl iodides has been developed. Benefitting from the pincer ligand, a variety of heterocycles, such as thiophenes, morpholine, unprotected indoles, pyrrole, pyridine, pyrimidine, furan, thiazole, pyrazole, benzothiadiazole, and triazole, are compatible here.

A new cobalt-catalyzed carbonylative synthesis of free (NH)-tetrahydro-β-carbolinones from tryptamine derivatives has been developed. A variety of free (NH)-tetrahydro-β-carbolinones were produced in good yields. The oxidant, silver salt, can be recycled and reused.

The synthesis of diverse products from the same starting materials is always attractive in organic chemistry. Here, a palladium-catalyzed substrate-controlled regioselective functionalization of unactivated alkenes with trifluoroacetimidoyl chlorides has been developed, which provides a direct but controllable access to a variety of structurally diverse trifluoromethyl-containing indoles and indolines. In more detail, with respect to γ,δ-alkenes, 1,1-geminal difunctionalization of unactivated alkenes with trifluoroacetimidoyl chloride enables the [4 + 1] annulation to produce indoles; as for β,γ-alkenes, a [3 + 2] heteroannulation with the hydrolysis product of trifluoroacetimidoyl chloride through 1,2-vicinal difunctionalization of alkenes occurs to deliver indoline products. The structure of alkene substrates differentiates the regioselectivity of the reaction.

A new process for the synthesis of arylacetamides has been explored through a palladium-catalyzed reductive desulfonative aminocarbonylation reaction of benzylsulfonyl chlorides with nitroarenes.

A facile and straightforward approach for the expedite construction of indole-3-carboxamide skeletons via a palladium-catalyzed carbonylative cyclization of 2-ethynylanilines with nitroarenes has been developed.

A nickel-catalyzed carbonylative domino cyclization of arylboronic acid pinacol esters with 2-alkynyl nitroarenes has been developed.

We report here a cooperative Cu/Pd-catalyzed multi-component borocarbonylation of ethylene with aryl iodides. A variety of synthetically useful β-boryl ketones were assembled from the most basic C1 (CO) and C2 (ethylene) building blocks in good yields.

Dimethyl carbonate (DMC), an environment-friendly compound prepared from CO2, shows diverse reactivities. In this communication, an efficient procedure using DMC as both a C1 building block and solvent in the aminocarbonylation reaction with nitro compounds has been developed. W(CO)6 acts both a CO source and a reductant here.

A nickel-catalyzed carbonylative cyclization of 2-nitroalkynes and aryl iodides has been developed for the expedite construction of N-benzoyl indole scaffolds. Using Co2(CO)8 as the CO source, this cascade reaction proceeded with high efficiency to give a variety of N-benzoyl indoles in moderate to high yields. Control experiments were performed as well to gain a better understanding of the reaction mechanism.

A palladium-catalyzed carbonylation of iminoquinones and aryl iodides has been developed for the construction of aryl p-amino benzoates. Using benzene-1,3,5-triyl triformate (TFBen) as the CO source, the reaction proceeded well to give various aryl p-amino benzoates in good to excellent yields. Additionally, control experiments were conducted to gain more insights into the reaction mechanism.

Herein, a facile and straightforward route to synthesize 3-trifluoromethyl-1,2,4-triazoles via copper-mediated [3 + 2] cycloaddition of trifluoroacetimidoyl chlorides and N-isocyanoiminotriphenylphosphorane (NIITP) has been described. Mo(CO)6 is utilized as an effective promotor to activate NIITP. The transformation features readily accessible reagents, mild reaction conditions, a broad substrate scope and high efficiency, and could be reproducible on a 3 mmol scale.

A palladium-catalyzed three-component carbonylative reaction of trifluoroacetimidohydrazides and aryl iodides for the synthesis of pharmaceutically valuable 5-trifluoromethyl-1,2,4-triazoles has been achieved. The reaction is characterized by a low catalyst loading amount, a broad substrate scope, high efficiency, no participation of CO gas and good application prospects. The protocol has been successfully applied to prepare the bioactive molecule GlyT1 inhibitor.

A palladium-catalyzed regioselective cyclocarbonylation of N-(2-pyridyl)sulfonyl (N-SO2Py)-2-iodoanilines with allenes has been developed. With the assistance of the directing group N-SO2Py, the regioselectivity of arylallenes was reversed and the reaction proceeded well to give various 3-methylene-2,3-dihydroquinolin-4(1H)-ones with up to 95% yield by using benzene-1,3,5-triyl triformate (TFBen) as the CO source. Control experiments and DFT calculations were performed to understand the reaction details and a possible reaction mechanism is proposed accordingly.

A nickel-catalyzed reductive aminocarbonylation reaction for the synthesis of α,β-unsaturated amides has been described. By employing vinyl triflates and nitroarenes as readily available starting materials, a wide range of α,β-unsaturated amide products were obtained in moderate to excellent yields with very good functional group tolerance in the absence of an external reductant. Notably, this is the first example of carbonylative synthesis of α,β-unsaturated amides by applying a Ni/Mo(CO)6 catalytic system with nitroarenes as promising nitrogen precursors. In addition, a late-stage modification of natural products was also achieved via this reductive aminocarbonylation approach.

The construction of structurally complexed and high-value chemical molecules from simple and readily available feedstocks is a long-standing challenge to chemists. Here, we describe a copper-catalyzed borofunctionalization of styrenes with B2pin2 and carbon monoxide. A set of new sodium cyclic borates were obtained with NaOtBu as the base. These unique sodium cyclic borates can be easily converted into a variety of multifunctional β-boryl vinyl esters, boryl carbonates, β-boryl aldehydes, and boryl vinyl ether. In addition, the procedure also features good functional group tolerance and utilizes CO as the C1 source.

A palladium-catalyzed 1,2-amino carbonylation of 1,3-dienes with (N-SO2Py)-2-iodoanilines has been developed for the construction of 2,3-dihydroquinolin-4(1H)-one scaffolds. Using benzene-1,3,5-triyl triformate (TFBen) as the CO source under the assistance of the N-SO2Py directing group, the reaction proceeded well to afford various 2,3-dihydroquinolin-4(1H)-ones in good yields (up to 88%). The effect of the directing groups was investigated and control experiments were performed to have a better understanding of the reaction pathway.

In this communication, a transition-metal-free deaminative carbonylation of activated alkylamines with thiophenols has been developed. Thioesters with various substituents were produced in moderate to good yields through Katritzky salt intermediates.

A cobalt-catalyzed domino Pauson–Khand and [4 + 2] cycloaddition of substituted diynes has been developed for the rapid construction of complexed polycyclic ring systems. Using benzene-1,3,5-triyl triformate (TFBen) as the CO source, the reaction proceeded well to give various tetracyclic compounds bearing two new quaternary carbon cores in high yields with excellent regioselectivity and diastereoselectivity. Control experiments were performed to gain a better understanding of the reaction mechanism.

A metal-free oxidative cyclization of trifluoroacetimidohydrazides with methylhetarenes for the efficient synthesis of 3-hetaryl-5-trifluoromethyl-1,2,4-triazoles has been developed. Notable features of this protocol include readily accessible starting materials, a broad substrate scope, high efficiency and scalability. The transformation provides a facile and straightforward route to valuable multi-functionalized 1,2,4-triazole derivatives.

A palladium-catalyzed carbonylative synthesis of N-acyl indoles from 2-alkynylanilines and aryl iodides has been developed. Using benzene-1,3,5-triyl triformate (TFBen) as the CO source, the reaction produced a variety of N-acyl indoles in a facile manner with high yields.

How to make a carbonylative coupling faster than the easier nucleophilic substitution? In this communication, a rhodium-catalyzed radical-based carbonylative coupling of alkyl halides with thiolphenols has been realized. Thioesters were isolated in good yields in general.

A metal-, azide- and CF3-reagent free approach for the synthesis of 5-trifluoromethyl-1,2,3-triazoles via base-mediated cascade annulation of diazo compounds with trifluoroacetimidoyl chlorides has been developed. Notable advantages of the reaction include readily available reagents, mild reaction conditions, a broad substrate scope, high efficiency, and promising synthetic utility. The protocol could be scaled up to the gram scale and be applied to construct the key skeleton of the analogue of LCRF-0004.

The preparation of fluorine-containing compounds has attracted considerable attention due to the important applications of their related chemicals. Among the candidates, trifluoroacetimidoyl halides are considered as potent trifluoromethyl synthons to construct a wide variety of trifluoromethyl-containing compounds and trifluoromethyl-substituted N-heterocycles, which have found extensive applications in the fields of organic synthesis, pharmaceuticals, agrochemicals, and materials science. In the review, recent advances in the synthetic applications of trifluoroacetimidoyl halides are summarized. We specially focused on two different reaction modes upon trifluoroacetimidoyl halides, namely, coupling and annulation reactions to illustrate their synthetic applications and potentials in the construction of valuable trifluoromethyl-containing molecules. Their preparations were covered as well.

A series of nanocrystalline copper–manganese oxides (denoted as Cu3−xMnx, x = 0, 1, 1.5, 2, 2.5, 3, where x means the molar ratio of Cu and Mn) were successfully prepared by a facile citric acid sol–gel method. The combination of Cu2+ and Mn3+ is intensified and enhanced interface effects generated, which is beneficial for the catalytic oxidation of benzene. A series of analyses, such as X-Ray Diffraction (XRD), N2 adsorption–desorption, X-ray photoelectron spectroscopy (XPS), and hydrogen temperature programmed reduction (H2-TPR), were employed to further investigate the structural properties of the catalysts. An optimal Mn/Cu ratio of 2 forms CuMn2O4 spinels. CuMn2 with CuMn2O4 spinel structure presents a larger specific surface area, smaller pore diameter as well as more lattice oxygen species, exhibiting remarkable activity and stability for the catalytic oxidation of benzene. On account of these factors, CuMn2 possesses better low temperature reducibility and shows the best catalytic performance with 90% benzene conversion at 186 °C. The enhanced catalytic activity of CuMn2 is attributed to the stabilization of CuMn2O4 active phases and the intensive synergistic effect between Cu–Mn oxides. To prove the effect of CuMn2O4 spinel structure on catalytic performance, a CuO/Mn2O3 mixed catalyst (molar ratio 1 : 1) was prepared and applied to benzene oxidation (T90% = 198 °C), which indicates that the spinel structure has an encouraging effect on benzene catalysis. The catalytic properties of single copper oxide and manganese trioxide were also tested, the results show that CuMn2O4 has a crucial role in facilitating electronic transmission and mobility of the lattice oxygen.

An efficient and straightforward palladium-catalyzed carbonylation of benzyl formates and tertiary amines has been explored. In this reaction, benzyl formates were successfully utilized both as CO surrogates and benzyl alcohol substrates, and a variety of arylacetamides were obtained in high yields with good functional group tolerance. Notably, tertiary amines were used as an amine source through a C–N bond cleavage pathway in the absence of additional oxidants.

A palladium-catalyzed three-component carbonylative reaction of trifluoroacetimidoyl chlorides and amines for the synthesis of valuable 2-(trifluoromethyl)quinazolin-4(3H)-ones has been developed. Broad substrate scope (41 examples), high efficiency (up to 99% yield) and no manipulation of CO gas constitute the notable features of this reaction. The present strategy can be applied to the late-stage modification of natural molecules and to the synthesis of the bioactive alkaloid molecule rutaecarpine.

A palladium-catalyzed carbonylative transformation of aryl iodides and sulfonyl chlorides has been studied. Both aryl and alkyl sulfonyl chlorides were all successfully transformed into the desired thioesters with sulfonyl chlorides as the sulfur source. Mo(CO)6 played a dual role as both CO surrogate and reductant in this reaction.

In this communication, we disclosed a palladium-catalyzed carbonylative procedure for the synthesis of 1-aroyl-3-aryl-1,5-dihydro-2H-pyrrol-2-ones from propargyl amines and aryl halides. By using TFBen as the CO source, the reaction provides a facile and straightforward access to various aryl-substituted 2-oxo-2,5-dihydropyrroles in good yields. The reaction mechanism is proven to be attractive as well.

An efficient copper-catalyzed aminoborylation of γ,δ-unsaturated aromatic oxime esters with bis(pinacolato)diboron has been developed. A variety of α-(borylmethyl)pyrrolidine derivatives were constructed in high yields under mild conditions. Notably, examples of converting the obtained aminoborylated product, including cycloaddition, oxidation, and coupling reactions, have been given as well.

A palladium-catalyzed double-carbonylative cyclization of propargyl alcohols and aryl triflates has been developed. Various 4-aroyl-furan-2(5H)-one scaffolds were produced in good yields with Cr(CO)6 as the CO source. Control experiments were performed as well, and a reasonable reaction mechanism was proposed.

A new method of low-cost copper-catalyzed carbonylative cyclization for preparing pyrrolidine-containing amides from γ,δ-unsaturated aromatic oxime esters and amines has been described. A range of readily available amines were examined, including primary, secondary, and heterocycle amines, giving over 60 examples of targeted N-heterocycle substituted amides with broad functional group tolerance, good chemical selectivity and moderate to excellent yields.

CuO–CeO2 nanocatalysts with different amounts of Mn dopping (Mn/Cu molar ratios of 0.5 : 5, 1 : 5 and 1.5 : 5) were synthesized by flame spray pyrolysis (FSP) method and tested in the catalytic oxidation of CO. The physicochemical properties of the synthesised samples were characterized systematically, including using X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FESEM), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), oxygen-temperature programmed desorption (O2-TPD), hydrogen-temperature programmed reduction (H2-TPR) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). The results showed that the 1Mn–Cu–Ce sample (Mn/Cu molar ratio of 1 : 5) exhibited superior catalytic activity for CO oxidation, with the temperature of 90% CO oxidation at 131 °C at a high space velocity (SV = 60 000 mL g−1 h−1), which was 56 °C lower than that of the Cu–Ce sample. In addition, the 1Mn–Cu–Ce sample displays excellent stability with prolonged time on CO stream and the resistance to water vapor. The significantly enhanced activity was correlated with strong synergetic effect, leading to fine textual properties, abundant chemically adsorbed oxygen and high lattice oxygen mobility, which further induced more Cu+ species and less formation of carbon intermediates during the CO oxidation process detected by in situ DRIFTS analysis. This work will provide in-depth understanding of the synergetic effect on CO oxidation performances over Mn doped CuO–CeO2 composite catalysts through FSP method.

Palladium-catalyzed direct carbonylation of propargyl alcohols for the synthesis of butenolides has been achieved. This transformation employs benzene-1,3,5-triyl triformate (TFBen) as the CO source and provides a facile and straightforward access to various substituted butenolides in high yields (up to 85%). Notably, phloroglucinol as the decomposed product of TFBen promotes the formation of butenolides.

A carbonylation procedure for the transformation of benzyl formates in organic carbonates has been developed. In this reaction, benzyl formates were successfully applied as both the CO source and benzyl alcohol substrates. Additionally, organic carbonates played multiple roles as a green solvent, an in situ activator, and a nucleophile in this procedure; various alkyl 2-arylacetates could be obtained in moderate to excellent yields.

Core–shell metal@ZnO nanoparticles including Au@ZnO, Pd@ZnO and Pt@ZnO were synthesized and utilized for sensing low-concentration benzene. Various techniques were used to characterize the compositional properties of the typical core@shell structure and analyze the relation between the sensing properties and the metal–ZnO hetero-interfaces. When applied as gas-sensing materials, all three core–shell metal@ZnO nanoparticles showed better sensing performance than pure ZnO nanoparticles towards low concentration benzene. In particular, the gas-sensing response of the Pt@ZnO core–shell nanoparticles was 7 times higher than that of pure ZnO towards 0.1 ppm benzene and 63 times higher towards 5 ppm benzene, which was more sensitive than most gas-sensing materials in previous literature. Furthermore, the Pt@ZnO core–shell nanoparticles presented an ultra-low detection limit of no less than 10 ppb, which was lower than those of most gas-sensing materials in previous literature. Besides, the Pt@ZnO core–shell nanoparticles showed high selectivity and long-term response stability with a response value of 2.7 ± 1.6% towards 1 ppm benzene after operating for a month. The enhanced gas-sensing performances of the metal@ZnO core–shell nanoparticles are well correlated to the work function differences between the contacted metal and ZnO within the metal–ZnO hetero-interfaces, which produce high Schottky energy barriers and modulate the electron transfer.

Herein, we disclose an interesting iron-catalyzed approach for the carbonylation of a tertiary carbon radical. The tertiary carbon radical generated from a 1,5-hydrogen atom transfer can be captured by CO gas smoothly. Various six-membered lactams were constructed chemo-selectively in high yields.

High performance methane gas sensors have become more and more essential in different fields such as coal mining, kitchens and industrial production, which necessitates the design and synthesis of highly sensitive materials. Herein, mesoporous SnO2 hollow spheres with high surface area (>90 m2 g−1) are prepared by a progressive inward crystallization routine, showing a high response of 1.31 to 250 ppm CH4 at a working temperature of 400 °C. Furthermore, loading noble metal Pd onto the surface of SnO2 hollow spheres by an adsorption–calcination process improves the response to 4.88 (250 ppm CH4) at the optimal dosage of 1 wt% Pd. Meanwhile, the working temperature decreases to 300 °C, showing the prominent spillover effect of catalytic Pd and PdO–SnO2 heterostructure sensitization as evidenced by the binding energy shift in the X-ray photoelectron spectroscopy (XPS) analysis. The response/recovery time is as short as 3/7 s and the sensitivity is stable for a test period as long as 15 weeks. All these performances show the promise of the highly porous Pd-loaded SnO2 hollow spheres for high performance methane sensors.

An interesting palladium-catalyzed procedure for the synthesis of amidines from arylsilanes, isocyanides and amines has been developed. Moderate to good yields of the desired amidines were produced in the absence of a phosphine ligand under oxidative conditions.

Herein we present a new strategy for the dehydrogenative-decarboxylative coupling of indoles with glyoxylic acid. A broad range of indoles were transformed into the corresponding 3-formylindoles in moderate to good yields and excellent functional group tolerance. Notably, no N-formylation product was detected under our conditions.

Various Cu-based composites for catalytic ozone decomposition have been synthesized by the reduction of Cu2+ using NH2OH·HCl in an aqueous solution without the addition of any extra etching agent. A Cu2O–CuO heterogeneous composite with many nanometer-sized CuO nanoplates distributed on the Cu2O surface as well as Cu(OH)2 nanowires was fabricated, and the structural evolution process was explored. The mechanism for the structure's formation can be attributed to the synergistic reaction of oxidation etching and acidic etching. It was found that the surface morphology and chemical composition of the nanostructures play important roles in catalyzing ozone decomposition. The Cu2O–CuO–Cu(OH)2 hierarchical nanostructure exhibits a 100% ozone (20 ppm O3 per air) decomposition efficiency at room temperature after 30 h of continuous operation, showing high stability. In addition, the hierarchical nanostructure also shows high moisture resistance, and the ozone conversion can still be above 80% at high relative humidity levels (ca. 90%) after a 16 h test. The excellent performance can be attributed to the delocalized holes speculated by EPR spectroscopy, which may facilitate the necessary electron transfer between intermediate oxygen anions and the catalytic surface.