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The first example of Cu-promoted cyclization of α-amino nitrile-tethered enynes incorporating an electron-deficient alkene component is described. A wide range of functionalized 3-azabicyclo[4.1.0]hepta-2,4-dienes and 4,5-dihydro-3H-azepines were prepared efficiently in a controllable manner. Moreover, the diverse cascade process enables efficient incorporation of tertiary amine moieties under mild reaction conditions. A possible reaction pathway is proposed on the basis of a series of control experiments.

A simple and facile copper-catalyzed synthesis of β-ketophosphine oxides via direct oxyphosphorylation of alkynes with H-phosphine oxides and dioxygen has been developed under mild conditions without any base or cocatalyst. A radical reaction pathway for the formation of β-ketophosphine oxides is proposed. An 18O labeling experiment suggested that the carbonyl oxygen atom of β-ketophosphine oxides originated from dioxygen.

An iodine mediated intramolecular C—H amination of N-2-pyridyl substituted electron rich anilines is developed to produce pyrido[1,2-a]benzimidazoles in good yields, in general.

Benzo[h]-naphth[1,2-f]quinazolines and benzo[h]-phenanthren[9,10-f]quinazoines were synthesized from intermediates 4-(2-hydroxyphenyl)-5-(naphthalen-1-yl)pyrimidines and 4-(2-hydroxyphenyl)-5-(phenanthren-1-yl) pyrimidines by the intramolecular dehydration of photocyclization. The intermediates were obtained by the condensation of 3-arylchromone with formamidine, acetamidine or guanidine refluxing in ethanol, respectively. Irradiation of the corresponding intermediates by a high-pressure mercury lamp in 19:1 (v/v) EtOH H2O or 18:1:1 (v/v) EtOH H2O-Dioxane lead to target products. This photocyclization showed advantages including catalyst-free and mild reaction condition. Moreover, water was the only by-product of this reaction. The crystal structure of 2-amino-12-methoxy-benzo[h]-naphth[1,2-f]quinazoline was determined and the fluorescence properties of these polybenzoquinazolines were also investigated.

An efficient copper-catalyzed decarboxylative coupling of cinnamic acids with N-fluorobenzenesulfonimide (NFSI) to give the corresponding substituted (E)-amination products stereospecifically is demonstrated. This new method is efficient and practical, and the corresponding products were obtained in moderate to good yields. The present protocol should broaden the scope of the decarboxylative cross-coupling reactions and provide a useful strategy for the construction of C–N bonds.

Two new steroidal glycosides, cynotophyllosides K (I) and L (II), are isolated from the roots of Cynanchum otophyllum together with three known steroids.

A convenient and cost-effective NaOH-promoted direct sulfenylation of pyrazolones with aryl thiols has been developed under mild and metal-free conditions. In this transformation, a range of valuable sulfenylated pyrazoles can be easily achieved in moderate to excellent yields, with high atom efficiency and good functional group tolerance.

A simple and catalyst-free method has been developed for the construction of β-hydroxyphosphine oxides through direct difunctionalization of alkenes with H-phosphine oxides and dioxygen under mild conditions. Preliminary mechanistic studies indicated that the hydroxyl oxygen atom of β-hydroxyphosphine oxide originated from the dioxygen and the present reaction might involve a radical process.

A convenient and efficient copper-catalyzed domino method has been initially developed for the synthesis of benzo[d]imidazo[5,1-b]thiazole derivatives via the reactions of readily available substituted o-bromoarylisothiocyanates with isocyanides under ligand-free conditions. This chemistry involves intermolecular [3 + 2] cycloaddition and intramolecular Ullmann-type C–S bond formation.

A direct difunctionalization protocol of alkenes with nitriles and thiols toward β-acetamido sulfide derivatives has been proposed under metal-free synthesis conditions. The present protocol provides the facile and highly efficient synthesis of various β-acetamido sulfides in a scaled-up manner with good to excellent yields simply using inexpensive molecular iodine as a catalyst, DMSO as a mild oxidant, and readily available thiols as thiolating reagents.

This stereoselective method relies on an organo-catalyzed asymmetric Diels—Alder reaction/iminium ion-induced cyclization sequence.

We have successfully developed a novel and efficient catalyst-free method for the synthesis of 3-nitroso-substituted imidazopyridines, from readily available imidazo[1,2-a]pyridines and tert-butyl nitrite, in good to excellent yields. Importantly, the use of transition-metal catalysts, stoichiometric amounts of acids, and toxic or potentially dangerous oxidants is avoided. This easy and practical method complements nitrosation reactions by expanding the scope and practicality, and should attract much attention in synthetic and pharmaceutical chemistry.

Pd-catalyzed decarboxylative Heck-type coupling of 3-chlorobenzo[b]thiophene-2-carboxylic acids with styrenes have been developed as an efficient strategy for the construction of functionalized benzo[b]thiophenes. Theoretical analysis shows that AgCl generated during the reaction, instead of Pd, π-coordinates with the carboxyl O atom, making easy the rate-determining CO2 dissociation. The divergent reactivities of the Cl-substituted and H-substituted 3-benzo[b]thiophene-2-carboxylic acids are mainly due to the presence of the Cl substituent, which reduces the adjacent π–π interplay, thereby significantly contributing to decarboxylation. Therefore, the presence of both AgCl and the Cl substituent are of key importance in ensuring the occurrence of the reaction under the given conditions.

The copper-catalyzed double C–S bond formation via Ullmann-type S-arylation and C–H thiolation using K2S as a sulfur source is described. This novel one-step sulfur-incorporation method provides a straightforward avenue to benzo[b]thiophene and imidazo[1,2-a]pyridine frameworks.

A highly regioselective TBHP-mediated ring opening of imidazopyridines via cleavage of C–C and C–N bonds has been achieved for the first time to afford N-(pyridin-2-yl)benzamides. Preliminary mechanistic investigations revealed that the present metal-free transformation involved a radical pathway, and the oxygen atom incorporated in the end products might derive from TBHP.

One new diketopiperazine alkaloid amauromine B (1), along with three known meroterpenoids, austalide B (2), austalides N and O (3 and 4), and two known steroids (5 and 6), was isolated and identified from the culture broth of the fungus Aspergillus terreus 3.05358. Their structures were elucidated by extensive spectroscopic techniques, including 2D-NMR and MS analysis, the absolute configuration of 1 was unambiguously established by single crystal X-ray diffraction analysis. All the isolates were evaluated for their inhibitory effects on α-glucosidase. Amauromine B (1) and austalide N (3) exhibited more potent α-glucosidase inhibitory activities than the positive control acarbose.

A direct approach for the highly regioselective thiocyanation of imidazoheterocycles through C—H functionalization is realized.

Crystalline [Me2NH][Sb4S5(S3)] is prepared by a surfactant solvothermal reaction of Sb2S3 and S (1:7.5) together with DMF, H2N-NH2·H2O, and octylamine (autoclave, 160 °C, 6 d).

A new and convenient silver-catalyzed direct oxidative spirocyclization of alkynes with thiophenols is described. This methodology provides a simple and practical approach to various 3-thioazaspiro[4,5]trienones in moderate to good yields with high atom efficiency and excellent functional group tolerance.

A novel iodine-catalyzed method for the synthesis of benzothiophene derivatives through cascade reactions of substituted thiophenols with alkynes has been demonstrated under metal- and solvent-free conditions. The present protocol uses inexpensive and environmentally friendly molecular iodine as the catalyst, and the corresponding products are obtained in moderate to excellent yields. Such an efficient, economical, and green transformation should provide an attractive approach to various benzothiophenes within organic and medicinal chemistry.

A novel and efficient procedure for direct difunctionalization of alkenes with I2O5 and P(O)–H compounds has been developed under metal-free conditions. The present methodology produces a series of substituted β-iodophosphates in moderate to good yields with high regioselectivity and favorable functional group tolerance.

A simple and convenient procedure has been developed for the construction of α-hydroxyketone phosphates via I2O5/DBU mediated direct α-phosphoryloxylation of ketones with H-phosphonates. This new reaction proceeds through three steps involving α-iodination of ketones, oxidation of H-phosphonates, and nucleophilic substitution of α-iodo ketones to access a series of α-hydroxyketone phosphates of biological importance.

Optimized conditions allow the direct thiolation of various methoxybenzenes, aniline (IVc) and heteroaromatic compounds.

A novel, efficient, and catalyst-free strategy has been initially developed for the construction of thioesters via the direct radical oxidative decarboxylation of α-keto acids with thiols, and the corresponding target products were obtained in moderate to good yields. It offers an alternative approach for the synthesis of useful diverse thioesters.

Iodine-catalyzed direct arylthiation of substituted anilines for the synthesis of various diaryl sulfides has been developed under metal- and solvent-free conditions. The present method uses readily available thiols as the arylthiation reagents, and environmentally friendly and inexpensive I2 as the catalyst. Importantly, no base or ligand was necessary. Such a simple, efficient, and economical transformation provides an attractive approach to various diaryl sulfides in good to excellent yields.

ZnHg3Se2Cl4 is prepared by solid state reaction of Hg2Cl2, Zn, and Se powder in the molar ratio of 2:1:2, resp.

A light-induced, BiOBr nanosheets accelerated intermolecular one-pot tandem trifluoromethylation/arylation of alkenes was presented. With this method, a series of CF3-containing aza-heterocycles with high selectivity were fabricated in moderate to good yields. Preliminary mechanistic studies revealed that the exceptional transformation was originated from the synergistic effect of photogenerated electrons and holes. Density function theory (DFT) was adopted to understand the high selectivity of this photocatalytic chemical transformation.

The tandem process for the preparation of the biologically important scaffolds includes sulfonylation of the alkyne substrates, ipso-carbocyclization, dearomatization, hydration and oxidation.

A novel sulfa-Michael addition (SMA)-triggered tandem reaction is developed by combining a SMA reaction with a simultaneous rearomatization process utilizing a less reactive carbonyl group as an intramolecular electrophilic partner.

A metal-free direct hydrosulfonylation protocol of azodicarboxylates with sulfinic acids has been developed for the construction of sulfonylhydrazine-1,2-dicarboxylates at room temperature. This methodology provides an efficient and practical approach to prepare various sulfonylhydrazine-1,2-dicarboxylates in good to excellent yields, which has the advantages of operation simplicity, environmental friendliness, high atom economy, and mild reaction conditions.

A novel asymmetric synthetic approach for the construction of enantioenriched functionalized dihydroquinones incorporating adjacent quaternary and tertiary stereocenters is reported.

A green synthesis of vinyl sulfones is performed by sulfonylation of styrenes with sodium arylsulfinates.

A silver-catalyzed double-decarboxylative protocol has been proposed for the construction of chalcone derivatives via cascade coupling of substituted α-keto acids with cinnamic acids under the mild aqueous conditions. The developed method for constructing C-C bonds via double-decarboxylative reactions is efficient, practical, and environmentally benign by using the readily available starting materials. It should provide a promising synthesis candidate for the formation of diverse and useful chalcone derivatives in the fields of synthetic and pharmaceutical chemistry.

When α-methyl styrenes are used as substrates the corresponding allylic sulfones (VII) are obtained instead of the expected β-bromo sulfones.

Aryl alkynoates (I) are coupled with β-keto acids (II) giving coumarin derivatives (III) in moderate to good yields.

The synthesis of β-selective allylic 1,2-dihydroisoquinolines with high E/Z selectivity is achieved from the γ-allylic regioisomers under mild conditions either by warming or by catalysis with a Lewis base.

A wide range of the title compounds (III) is efficiently obtained from simple and easily available starting materials with excellent stereo- and regioselectivity and without use of any metal catalyst or additives.

A series of 3-sulfonated coumarins is readily prepared by Bu4NI-catalyzed oxidative arylsulfonylation of alkynes.

The first catalytic stereoselective approach to prepare multiple substituted cyclic nitriles by means of a novel metal-free intramolecular carbocyanation strategy has been developed, which provided an efficient protocol to construct densely functionalized diastereoenriched pyrrolo[2,1-a]isoquinoline derivates under mild reaction conditions (up to 20/1 d.r., 98% yield).

The metal-free oxidative coupling of methyl ketones with primary amines is operationally simple, proceeds under mild aerobic conditions and furnishes amides in good to excellent yields.

A novel Lewis base-promoted rearrangement of allylic cyanohydrins has been developed, in which the cyano group was rearranged, directly coupled with the generation of new functional groups. This protocol provides a unique and facile way to prepare highly functionalized nitriles bearing 1,3-diketone moieties under mild reaction conditions. Furthermore, the synthetic transformations of the functionalized products have also been demonstrated.

The evolution of photoelectrochemical (PEC) bioanalysis has resulted in substantial progress in its analytical performance and biodetection applications. The aim of this review is to provide a panoramic snapshot of the state of the art in this dynamically developing field, with special emphasis on PEC DNA analysis, immunoassay, enzymatic biosensing and cell-related detection. The future prospects in this area are also evaluated and discussed. This work will serve as a useful source to inform the interested audience of the latest developments and applications in the field of PEC bioanalysis.