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CO2-Driven reversible phase transfer of amine-functionalized ZIF-90 has been used for trans-esterification to achieve efficient coupling of reaction, separation, and component recycling for green sustainable processes.

An unprecedented water oxidation reaction by a small organic molecule is observed for the first time. This led to the facile synthesis of thioethers via Brønsted acid-catalyzed reactions of alcohols, alkenes, and alkynes with advantageous disulfides.

Phase transfer of metal-organic frameworks is highly desired in many areas, which remains a challenge. Herein, we present for the first time a CO

Owing to the small electronegativity of the sulfur atom, it is commonly supposed that at most one weak H-bond can be formed between a sulfur atom and an H-bond donor. In this paper, an unprecedented 2 : 1 binding species generated from two molecules of phenol and a molecule of thioether was observed and characterized by various nuclear magnetic resonance (NMR) techniques, Fourier transform-infrared (FT-IR) techniques and density functional theory (DFT) calculations, revealing the formation of sulfur-centred O-H⋯S⋯H-O bifurcated H-bonds. This work may provide a simple and efficient method for the quantitative analysis of weak H-bonds between small organic molecules.

Herein, we report a palladium-catalyzed relay Heck-type reaction of fluoroalkyl bromide and terminal alkenes. The reaction involves fluoroalkylation of alkenes and migration of double bonds via a 1,5-hydrogen atom transfer strategy. Through this method, a series of remote fluoroalkylated alkenes was obtained under mild conditions.

The first experimental evidence for the palladium-catalyzed secondary bond activation of allylic alcohols in a Tsuji–Trost reaction was provided by NMR methods, such as variable-temperature 1H NMR,...

A substrate self-assisted activation of allylic alcohols by tautomerizable heteroarenes via hydrogen bonding was disclosed by various NMR techniques, including variable-temperature 1H NMR, Job plot, and 1H NMR titration. Guided by these finding, a much milder allylic substitution of tautomerizable heteroarenes with allylic alcohols was developed, affording the target products in high yields.

A convenient and precise nitration and oximation of alkenes with tert-butyl nitrite has been reported, yielding α-nitro ketoximes in satisfactory yields with broad substrate generality and excellent stereoselectivity under mild conditions. Experiments indicate that tert-butyl nitrite serves as both NO and NO2 sources and water plays a key role in this difunctionalization reaction.

A practical and efficient method for selective intramolecular radical trifluoromethylacylation and -arylation of alkenes with inexpensive CF3SO2Na and K2S2O8 in aqueous media has been developed, respectively, affording the highly chemoselective synthesis of CF3-functionalized chroman-4-ones and chromanes in satisfactory yields. Control experiments and DFT calculations indicate that the CF3SO2Na/K2S2O8 system is capable of trifluoromethylating the substrate of alkenes without a transition metal catalyst and the oxidation of CF3SO2Na to ·CF3 by K2S2O8 is involved in the rate-determining step.

The famous Michaelis–Arbuzov reaction is extensively used both in the laboratory and industry to manufacture tons of widely-used organophosphoryl compounds every year. However, this method and the modified Michaelis–Arbuzov reactions developed recently still have some limitations. We now report a new alcohol-version of the Michaelis–Arbuzov reaction that can provide an efficient and environmentally-benign method to address the problems of the known Michaelis–Arbuzov reactions. That is, a wide range of alcohols can readily react with phosphites, phosphonites, and phosphinites to give all the three kinds of phosphoryl compounds (phosphonates, phosphinates, and phosphine oxides) using an n-Bu4NI-catalyzed efficient C–P(O) bond formation reaction. This general method can also be easily scaled up and used for further synthetic transformations in one pot.

By screening the copper catalysts, ligands, and the reaction conditions, a simple CuCl/DMEDA/TEMPO catalyst system readily available from commercial sources is developed for a direct and selective synthesis of the useful nitriles by an aerobic oxidation reaction of primary amines using air as an advantageous oxidant under mild conditions.

A metal- and base-free three-component coupling of alcohols, heteroaryl halides, and thiourea has been developed for direct and selective synthesis of heteroaryl thioethers. This method can be easily scaled up to the gram scale and extended to dialkyl thioethers, heteroaryl selenides, benzothiazoles, and some antimycobacterially-active thioethers. Mechanistic studies revealed that a by-product-promoted in situ C–O activation of alcohols to more reactive alkyl halides and slow release of the thiol and alkyl halide intermediates are the key to the high selectivity and success of the reaction.

It is observed the crystal water in sodium thiosulfate pentahydrate (Na2S2O3·5H2O) can promote its multicomponent reaction with heteroaryl chlorides and alcohols, providing a facile, green, and spe...

By altering the amount of Selectfluor, the highly selective mono- and difluorination of 1,3-dicarbonyl compounds has been achieved, affording a variety of 2-fluoro- and 2,2-difluoro-1,3-dicarbonyl compounds in good to excellent yields. The reaction can be readily performed in aqueous media without any catalyst and base, which features practical and convenient fluorination. Importantly, a gram-scale reaction, transformation of 2-fluoro-1,3-diphenylpropane-1,3-dione to 4-fluoro-1,3,5-triphenyl-1H-pyrazole, and chlorination and bromination of 1,3-dicarbonyl compounds are realized to further exhibit its synthetic utility.

By catalyst and condition screening, a simple method for the synthesis of benzazole and quinoxaline heterocycles via Cu-catalyzed direct aerobic oxidative cyclocondensation of o-thio/hydroxy/aminoanilines and amines was developed by using air as the safe, cheap, effective, and clean oxidant. Due to the observed great promoting effect of the substrates on the reaction, single CuI can be used as the efficient catalyst without requiring additional oxidation co-catalysts. This method provides a simple and practical way for preparation of the useful benzothiazoles, benzimidazoles and benzoxazoles from amines.

Using only catalytic amounts of alkyl halides in the reactions of poor nucleophilic amines/amides and alcohols led to a selective Hofmann N-alkylation reaction catalytic in alkyl halides, providing a practical and efficient method for the practical synthesis of mono- or di-alkylated amines/amides in high selectivities. This new method avoids the use of large amounts of bases, alkyl halides, and solvents, and generates water as the only byproduct. Preliminary mechanistic studies showed that alkyl halides are key intermediates/catalysts regeneratable in the reaction cycle.

An efficient alkali hydroxide-mediated SNAr reaction of heteroaryl halides has been developed for the practical synthesis of the useful unsymmetrical heteroaryl thioethers and chalcogenides. The usually odorless, easily available, lowly toxic, and easily stored and handled diorganyl dichalcogenides can be used as safer and convenient chalcogen nucleophile precursors and diverse unsymmetrical heteroaryl chalcogenides can be obtained in good to high yields by the method.

Alcohols can be efficiently converted into the useful thioethers by a transition metal- and base-free dehydrative S-alkylation reaction with thiols or disulfides by employing alkyl halides as the effective catalyst. This simple and efficient method is a green and practical way for the preparation of thioethers, as it tolerates a wide range of substrates such as aryl and alkyl thiols, as well as benzylic, allylic, secondary, tertiary, and even the less reactive aliphatic alcohols.

Using only catalytic amounts of alkyl halides in the reactions of poor nucleophilic amines/amides and alcohols led to a selective Hofmann N-alkylation reaction catalytic in alkyl halides, providing a practical and efficient method for the practical synthesis of mono- or di-alkylated amines/amides in high selectivities. This new method avoids the use of large amounts of bases, alkyl halides, and solvents, and generates water as the only byproduct. Preliminary mechanistic studies showed that alkyl halides are key intermediates/catalysts regeneratable in the reaction cycle.

An efficient alkali hydroxide-mediated SNAr reaction of heteroaryl halides has been developed for the practical synthesis of the useful unsymmetrical heteroaryl thioethers and chalcogenides. The usually odorless, easily available, lowly toxic, and easily stored and handled diorganyl dichalcogenides can be used as safer and convenient chalcogen nucleophile precursors and diverse unsymmetrical heteroaryl chalcogenides can be obtained in good to high yields by the method.

Owing to the importance of amine/amide derivatives in all fields of chemistry, and also the green and environmentally benign features of using alcohols as alkylating reagents, the relatively high atom economic dehydrative N-alkylation reactions of amines/amides with alcohols through hydrogen autotransfer processes have received much attention and have developed rapidly in recent decades. Various efficient homogeneous and heterogeneous transition metal catalysts, nano materials, electrochemical methods, biomimetic methods, asymmetric N-alkylation reactions, aerobic oxidative methods, and even certain transition metal-free, catalyst-free, or autocatalyzed methods, have also been developed in recent years. With a brief introduction to the background and developments in this area of research, this chapter focuses mainly on recent progress and technical and conceptual advances contributing to the development of this research in the last decade. In addition to mainstream research on homogeneous and heterogeneous transition metal-catalyzed reactions, possible mechanistic routes for hydrogen transfer and alcohol activation, which are key processes in N-alkylation reactions but seldom discussed in the past, the recent reports on computational mechanistic studies of the N-alkylation reactions, and the newly emerged N-alkylation methods based on novel alcohol activation protocols such as air-promoted reactions and transition metal-free methods, are also reviewed in this chapter. Problems and bottlenecks that remained to be solved in the field, and promising new research that deserves greater future attention and effort, are also reviewed and discussed.