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Dearomatization of indole is a useful strategy to access indolimines: a motif widely exists in biologically active molecules and natural products. Herein, an efficient method for the dearomatization of 2,3-disubstituted indoles to generate diverse indolimines with tetrasubstituted allenes is described. This work accomplishes dearomatization of 2,3-disubstituted indoles through 1,8-addition of (aza)-para-quinone methides, which are generated in situ from propargylic alcohols. A series of synthetically useful indolimines containing quaternary carbon centers and tetrasubstituted allenes can be accessed in good yields (up to 99%). Additionally, the separability of product isomers, diversified product transformations, and easy scale-up of the reaction demonstrate the potential application of this method.

An efficient method for the stereoselective synthesis of (Z)-3-((arylamino)methylene)indoline-2-thiones have been developed via a novel multicomponent reaction of indoles, CS2 and nitroarenes. A range of functionalized indoline-2-thiones were prepared in moderate to good yields from easily available starting materials. The indoline-2-thione products can be easily derivatized to give biologically active thieno[2,3-b]indole and thiopyrano[2,3-b]indole skeletons in high yields.

A visible-light-induced carbonylation of indoles with phenols for the synthesis of indole-3-carboxylates has been developed. The reaction proceeded via a radical carbonylation process in which elementary I2 was used as an effective photosensitive initiator and, thus, avoided the use of transition metal catalysts. A series of different aryl indole-3-carboxylates were prepared in moderate to good yields. The broad applicability of this methodology was further highlighted by the late-stage functionalization of several phenol-containing natural products and pharmaceuticals.

A novel Bronsted acid catalyzed 1,8-addition mediated (3 + 4)-annulation of in situ generated propargylic p-quinone methides with 2-indolylmethanols is described. This method provides a convenient and mild approach to structurally interesting and synthetically important polysubstituted indole-fused oxepines in high yields. Moreover, 2-indolylmethanols as four-atom synthons in the (3 + 4)-annulations under Bronsted acid conditions have been explored for the first time.

Herein, we describe a highly effective 1,8-conjugate-addition-mediated formal (3+3)-annulation of (aza)-para-quinone methides in situ generated from propargylic alcohols with 4-hydroxycoumarins and 1,3-dicarbonyl compounds under the catalysis of a Bronsted acid. This methodology affords efficient and practical access to synthetically important and highly functionalized pyranocoumarins and pyrans in excellent yields under mild conditions. Importantly, these products exhibit impressive inhibitory activity toward α-glucosidase.

An efficient synthesis of disubstituted γ-butyrolactones and spirocyclopropanes via a multicomponent reaction of aldehydes, Meldrum's acid and sulfoxonium ylides has been developed. Under mild conditions, electron-rich aromatic aldehydes reacted with Meldrum's acid and sulfoxonium ylides and produced trans-β,γ-disubstituted γ-butyrolactones, while neutral and electron-deficient aromatic aldehydes and aliphatic aldehydes led to the formation of trans-spirocyclopropanes. The cyclopropane could be converted to the γ-butyrolactone under Lewis acid conditions.

A novel spiro-pyrrolidine (SPD)-derived bifunctional thiourea catalyst has been developed, enabling the development of a stereoselective conjugate addition of furfurals to β,γ-unsaturated α-ketoesters. The reaction represents an example of asymmetric trienamine catalysis in the benzylic C–H functionalization of 5-benzylfurfurals, and the rigid spirocyclic framework of the catalyst is proven to be essential for a highly enantioselective transformation.

Herein, we report an efficient Bronsted acid-catalyzed formal (3+3)-annulation of (aza)-para-quinone methides generated in situ from propargylic alcohols with naphthol derivatives, which involves a 1,8-conjugate addition/6-endo annulation process. This protocol provides an effective method for preparing important functionalized pyranocoumarins under mild conditions.

An efficient and straightforward Lewis-acid-mediated stereoselective (4 + 3)-cyclization of indole-substituted alkylidene malonates and donor-acceptor cyclopropanes has been developed involving the Friedel-Crafts/Michael addition cyclization cascade. This reaction provides a mild and effective method for the construction of synthetically and structurally interesting functionalized cycloheptannelated indoles.

As a special functional and structural material, the rare metal beryllium has been widely applied in many key areas due to its excellent nuclear properties, optical properties and physical properties such as low density, high specific stiffness, high specific strength, and excellent thermal properties. This article systematically reviews application of beryllium in strategic nuclear energy, high-energy physics, inertial navigation systems, aircraft structural components, optical systems and commercial fields. The paper also examines how beryllium promoted technological advances and improved the facilities performance in its applications fields. Beryllium plays an important role in the development of nuclear technology, defense, and aerospace, which make beryllium become a strategic and critical engineering material. The paper provides a reference for scientists and technicians to employ beryllium in more fields.

A new polysaccharide (MIPW50-1) with a molecular weight of 28.5 kDa was isolated from Morchella importuna fruiting bodies. Structural analysis indicated that MIPW50-1 was composed of N-acetylglucosamine, galactose, glucose, and mannose with molar ratios of 1.00:14.95:1.53:10.51, and its structure was characterized as a repeating unit consisting of →2,3,6)-α-D-Manp-(1→, →3,6)-α-D-Manp-(1→, →2)-α-D-Galp-(1→, →6)-α-D-Manp-(1→, →4)-β-D-Glcp-(1→, →4)-α-D-GlcpNAc-(1→, →6)-α-D-Glcp-(1→, α-D-Galp-(1→, α-D-GlcpNAc-(1→ and β-D-Glcp-(1→. The immunoregulatory effect of MIPW50-1 was also evaluated. MIPW50-1 was capable of stimulating macrophage function, rising phagocytosis of RAW264.7 cells as well as promoting secretion of NO, TNF-α and IL-6. Moreover, the immunoblot and ELISA assays demonstrated that MIPW50-1 exerted immune-potentiating effect through the TLR4/JNK and Akt/NF-κB signalling pathways in RAW264.7 cells. This is the first polysaccharide containing N-acetylglucosamine isolated from Morchella mushrooms, and MIPW50-1 might be used as one of potential immunoenhancing components in functional foods.

A tunable procedure on palladium-catalyzed carbonylative divergent synthesis of α , β -unsaturated amides and maleimides from symmetrical internal alkynes and nitroarenes has been developed. By using Pd(acac) 2 /dppp/4-ClBSA/DMF and Pd(TFA) 2 /DPEphos/PTSA/H 2 O/toluene as the catalytic systems, a range of multi-substituted maleimides and α , β -unsaturated amides were selectively prepared in moderate to good yields with Mo(CO) 6 as the solid CO source and nitroarene as a cheap and abundant nitrogen source.

A palladium-catalyzed aminocarbonylation of aryl boronic acids with nitroarenes for the synthesis of amides has been developed. A wide range of substrates were well-tolerated and gave the corresponding amides in moderate to good yields. No external oxidant or reductant was needed in this procedure. This procedure provides a redox-economical process for the synthesis of amides.

The carbonylative coupling of aryl halides with unactivated alkenes remains a challenge, because of the low reactivity of acyl-palladium intermediate to the olefins. In this paper, a palladium-cata...

Summary Carbon monoxide is one of the most important C1 molecules in organic chemistry. Many novel procedures for its conversion have been developed, and some have even been industrialized. In this review, we discuss and categorize CO chemistry into four classes: (1) transition-metal-mediated carbonylation, (2) strong-acid-initiated cationic carbonylation, (3) anionic carbonylation, and (4) free-radical carbonylation. Relevant achievements are selected and discussed in detail.

Amide synthesis is one of the most important transformations in organic chemistry due to their ubiquitous presence in our daily life. In this communication, a palladium catalyzed cascade azidation / carbonylation of aryl halides for the synthesis of amides was developed. Both iodo- and bromobenzene derivatives were transformed to the corresponding amides using PdCl 2 / xantphos as the catalyst system and sodium azide as the nitrogen-source. The reaction proceeds via a cascade azidation / carbonylation process. A range of alkyl and halogen substituted amides were prepared in moderate to good yields.

Substituents modification of BN-heterocycles on the boron atom has proven important to the photoreactivity and optoelectronic properties of BN-heterocycles. We developed a sequential and diverse synthetic strategy toward BN-heterocycles, in which the boron building block can be introduced with fully pre-functionalized substituents (Route A) or the substituents can be partially (Route B) or fully (Route C) modified after borylation. These three routes are complementary to provide more diverse BN-heterocycles, which will find broad applications in manipulating/controlling molecular transformations and the development of new photoresponsive materials.

A convenient palladium-catalyzed carbonylation reaction for the efficient synthesis of (E)-3-benzylidenechroman-4-ones has been developed. Using TFBen as a solid CO source, a range of substituted (E)-3-benzylidenechroman-4-ones were prepared in moderate to good yields with 2-iodophenols and allyl chlorides as the substrates. Additionally, substituted quinolin-4(1H)-ones can also be obtained with 2-iodoaniline as the starting material.

The homogeneous heteropolysaccharide CMSPW90-1 was first purified from bergamot by DEAE Sepharose Fast Flow and Sephadex G-75 column with a molecular weight of 18.8 kDa. The structure of CMSPW90-1 was elucidated with high-performance gel permeation chromatography, gas chromatography–mass spectrometry, infrared spectrum, methylation, nuclear magnetic resonance (NMR), Congo red test, and circular dichroism. In comparison with CMSPW90-1, the sulfated derivative CMSPW90-M1 showed significant ultra-structural differences with a molecular weight of 75.4 kDa. The antioxidant and immunomodulatory activities of CMSPW90-M1 were examined to determine the relationships of structure-bioactivity. CMSPW90-M1 exhibited stronger scavenging activities for DPPH and ABTS+ than those of CMSPW90-1. CMSPW90-M1 exhibited more immunomodulatory activity in vitro by promoting the proliferation of mouse splenocytes and the neutral red phagocytosis of RAW264.7 cells. The results demonstrated that CMSPW90-M1 could be developed as one of the potential free radical inhibitors and immunomodulators.

A new homogeneous heteropolysaccharide (CMSPA90-1) was purified from bergamot by DEAE sepharose fast flow and Sephadex G-75 columns, and was shown to have a molecular weight of 17.6 kDa. Its chemical structure was elucidated by acid hydrolysis and methylation analysis, along with high-performance anion-exchange chromatography, Fourier transform infrared spectroscopy coupled with gas chromatography-mass spectrometry, NMR spectroscopies, the Congo red test, and circular dichroism. CMSPA90-1 consisted of a pyranoside and funanside with branches containing α- and β-configurations simultaneously. Arabinose and glucose might form an arabinoglucan backbone. The ultrastructure of CMSPA90-1 was further characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results of thermogravimetric analysis (TGA) revealed that CMSPA90-1 had good thermal stability. The results of DPPH˙ and ABTS+˙ radical scavenging assays indicated that CMSPA90-1 exhibited free-radical-scavenging properties. Otherwise, CMSPA90-1 could promote the proliferation of mouse splenocytes and the neutral red phagocytosis of RAW264.7 cells, which indicated that CMSPA90-1 could be researched and developed as one of the potential functional foods or natural medicines.

A palladium-catalyzed four-component carbonylative cyclization reaction for the synthesis of 2,3-disubstituted quinazolin-4(3H)-ones has been developed. A range of different 2,3-disubstituted quinazolin-4(3H)-one derivatives were prepared in moderate to good yields employing simple and readily accessible 2-iodoanilines, nitro compounds and acid anhydrides as the synthetic precursors. Mo(CO)6 acted both as a solid CO source and a reductant. Notably, methaqualone as a sedative and hypnotic medication can be prepared easily in 68% yield (4b) under our conditions as well.

A gold-catalyzed regiospecific hydration of N-tosyl propargylic amines has been developed. In the presence of a catalytic amount of the gold catalyst NaAuCl4·2H2O, both alkyl and aryl-substituted N-tosyl propargylic amines were smoothly converted into the corresponding β-amino ketones with excellent regioselectivities and high yields (up to 85%). Further transformations of the obtained β-amino ketones to valuable 1,3-amino alcohols were demonstrated as well.

A procedure on palladium-catalyzed selective aminocarbonylation of styrenes with nitroarenes for the synthesis of α,β-unsaturated amides has been developed. A range of substituted α,β-unsaturated amides were synthesized in moderate to good yields. Interestingly, nitroarenes act as both a nitrogen source and oxidant, and Mo(CO)6 acts as a solid CO source and reductant in this catalytic system.

An efficient and convenient palladium-catalyzed carbonylative procedure for the synthesis of bis(indolyl)methanes has been established for the first time. With TFBen (benzene-1,3,5-triyl triformate) as the solid CO source, aryl iodides and indoles were transformed into the corresponding bis(indolyl)methane derivatives in moderate to excellent yields .

The main contributions in the field of first-row transition-metal-catalyzed (base-metal-catalyzed) carbonylative transformations have been summarized and discussed. The contents have been divided according to the electrophiles applied, followed by the different types of nucleophiles. Their reaction mechanisms and applications have been emphatically discussed.

Bottleneck issues such as difficult biofilm culturing, time-consuming granular formation and excessive nitrate production, always limited the application of anammox processes. By using the common but meaningful suspended activated sludge instead of biofilm or granule activated sludge, a combined anammox process, simultaneous partial nitrification, anammox and denitrification (SNAD), was established in a sequencing batch reactor (SBR) in this study to treat real domestic sewage and was operated for 300 days. Results indicated that a high ammonia removal rate and nitrogen removal rate (1.1 and 1.03 (kgN/(m3·d)), respectively) were achieved during the baseline phase treating high ammonia wastewater (350–550 mg/L). During the experimental phase treating domestic sewage with a C/N of 3–3.5, 86.1% of total nitrogen removal efficiency was achieved and only 1.02 mg/L of nitrate concentration was detected in the effluent with an averagely 64.6 mg/L of ammonium in the influent. Nitrogen mass balance analysis demonstrated that about 89% of total nitrogen (TN) was removed by anammox and the remaining 11% of TN was removed by denitrification. Bacterial abundance of Candidatus Brocadia and Thauera increased from 0.02% to 0.5% and 0.39% to 2.24% (from baseline phase to experimental phase), respectively, which made an essential contribution to the nitrogen removal. The advanced nitrogen removal performance reached in the SNAD process showed the possibility of using suspended sludge as a substitute of biofilm and granule sludge concerning anammox, and the process could treat real domestic sewage with a C/N of 3–3.5 without pretreatment of chemical oxygen demand (COD).

The development of highly selective procedures is one of the core goals in organic chemistry. Among the known organic transformations, carbonylation reactions present an ideal choice for the preparation of carbonyl-containing compounds. In this review, the recent achievements on the control of the selectivity for carbonylation reactions have been summarized. The effects of ligands, solvents, and bases on the selectivity are been discussed.

A Pd/C catalyzed reductive carbonylation of nitroarenes for the synthesis of unsymmetrical ureas has been developed. Using inexpensive and stable nitroarenes as the substrates, a series of unsymmetrical ureas were produced in moderate to good yields. A range of functional groups including thioethers, halides and vinyl were compatible with this reaction. As a heterogeneous catalyst, Pd/C was recycled and reused four times without losing activity. Notably, urea-based herbicide neburon was prepared in 64% yield under our standard conditions.

Quinolin-2(1H)-one is a useful structure unit present in a wide range of natural products and pharmaceuticals. A Pd(ii)-catalyzed synthesis of quinolin-2(1H)-ones from quinoline N-oxides was developed with azodicarboxylates which act as both the activating agent and oxidant. The reaction proceeded under mild conditions and no protection against air and moisture was needed.

A convenient palladium-catalyzed carbonylative homo-coupling of aryl iodides was developed. With formic acid as the CO source, various symmetrical diaryl ketones were synthesized in moderate to good yield in the presence of palladium catalyst.

A palladium-catalyzed Heck reaction of in-situ generated benzylic iodides and styrenes has been achieved. The reaction proceeds in a one-pot manner through 1) addition perfluoroalkyl iodides to styrenes to give benzylic iodides, 2) followed by a palladium-catalyzed Heck coupling of the resulting benzylic iodides with the same alkenes in high regio- and stereoselectivity. A variety of perfluoroalkylated alkenes were obtained in moderate to excellent yields .