Electro-oxidative coupling of Bunte salts with aryldiazonium tetrafluoroborates: a benign access to unsymmetrical sulfoxides

An electrochemical strategy for the synthesis of unsymmetrical sulfoxides has been explored using Bunte salts and aryldiazonium tetrafluoroborates under constant current electrolysis at room temperature. In addition to being eco-safe and using mild conditions, the present protocol is free from the use of metal/oxidant, and is endowed with a broad substrate scope and good functional group tolerance.

Synthesis of functionalized alkenes via Cu(I)-catalysed allylation of acetanilides using Morita-Baylis-Hillman bromides

An easy access to functionalized alkenes has been developed by the C-H functionalization of anilides with Morita-Baylis-Hillman (MBH) bromides in the presence of copper chloride, TBHP and acetic acid. Unsubstituted as well as ortho/meta-substituted anilides exclusively give rise to the para-allylated products, whereas para-substitution brings about the formation of ortho-allylated anilides.

Elemental sulfur as the “S” source: visible-light-mediated four-component reactions leading to thiocyanates

An eco-friendly and photocatalyst-free visible-light-promoted four-component reaction of α-diazoesters, elemental sulfur, cyclic ethers and TMSCN leading to thiocyanates is described.

Cellulose-reinforced poly(ethylene-co-vinyl acetate)-supported Ag nanoparticles with excellent catalytic properties: synthesis of thioamides using the Willgerodt–Kindler reaction

Cellulose, a bio-derived polymer, is widely used in food packaging, dye removal, coatings, and solid-supported catalysis. Heterogeneous catalysts play a critical role in environmental remediation. In this context, the demand for green and cost-effective catalysts has rapidly increased. In this study, cellulose was extracted from rice straw, and a highly active solid-supported catalytic model was developed. First, cellulose was conjugated with poly(ethylene-co-vinyl acetate) (PEVA), and then Ag nanoparticles (AgNPs) were inserted into the cellulose–PEVA composite. The process involved the reduction of AgNPs in the presence of sodium borohydride. The fabricated hybrid catalyst was characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray, and powder X-ray diffraction. Thereafter, the obtained hybrid was used as a catalyst for the Willgerodt–Kindler reaction of aromatic aldehydes, amines, and S₈ to synthesize thioamides with excellent yields. The developed catalytic system exhibited high stability and recyclability. Moreover, the mechanical properties of the hybrid catalyst were evaluated using tensile strength and impact tests. RGB analysis of digital images was also performed to investigate the primary components of the catalyst.

The AgNPs@cellulose–PEVA hybrid catalyst presented excellent catalytic efficacy for the Willgerodt–Kindler reaction, facilitating the selective formation of C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> S bonds.

Visible-light-promoted nitrone synthesis from nitrosoarenes under catalyst- and additive-free conditions

A green and sustainable nitrone formation reaction via visible-light-promoted reaction of aryl diazoacetates with nitrosoarenes is described. This protocol exhibits good functional group tolerance and broad substrate scope for both aryl diazoacetates with nitrosoarenes. Comparing the reported methods for the synthesis of nitrones from nitrosoarenes, the reaction described herein occurs under sole visible-light irradiation without the need of any catalysts and additives.

Synthesis of Dibenzo[d,f][1,3]Diazepines via Elemental Sulfur-Mediated Cyclocondensation of 2,2'-Biphenyldiamines with 2-Chloroacetic Acid Derivatives

The three-component reaction of 2,2'-biphenyldiamines with 2-chloroacetic acid derivatives and elemental sulfur was developed for the practical synthesis of unknown 2-carboxamide-substituted dibenzo[d,f][1,3]diazepines. This protocol is distinguished by efficiency in water and good tolerance to functional groups and can be adapted to a large-scale synthesis. The chemoselective preparation of a variety of 2-S,N,O-substituted dibenzo[d,f][1,3]diazepines was accomplished using the developed method.

Flexible Synthesis of Phosphoryl-Substituted Imidazolines, Tetrahydropyrimidines, and Thioamides by Sulfur-Mediated Processes

The solvent-free sulfur-mediated reactions of phosphinic chlorides with alkyl diamines were developed for the practical synthesis of unknown phosphoryl-substituted 4,5-dihydro-1H-imidazoles, 1,4,5,6-tetrahydropyrimidines, and thioamides. Their good tolerance to functional groups, broad substrate scope, and easy scalability were shown. The chemoselective preparation of a variety of phosphoryl-substituted bis(thioamides) was accomplished via the adjustment of a solvent.

Metal-free synthesis of imidazo[1,5-a]pyridines via elemental sulfur mediated sequential dual oxidative Csp3-H amination

A simple and efficient approach has been developed for the synthesis of imidazo[1,5-a]pyridines using the elemental sulfur mediated sequential dual oxidative Csp3-H amination of 2-pyridyl acetates and amines under metal- and peroxide-free conditions. Broad substrate scope, operational simplicity and gram-scale ability make this chemistry very practical.

Visible light enabled γ-trifluoromethylation of Baylis–Hillman acetates: stereoselective synthesis of trisubstituted alkenes

Metal-free γ-trifluoromethylation of Baylis–Hillman acetates is reported using Langlois’ reagent under visible light photoredox catalysis.

Transition-Metal-Free Regiospecific Aroylation of Nitroarenes Using Ethyl Arylacetates at Room Temperature

A novel regiospecific C(sp³)-C(sp²) coupling between ethyl arylacetates and nitroarenes has been developed to deliver biaryl ketones in excellent yields. The protocol is metal-free, mild, and compatible with a number of functional groups on both of the reacting partners.

The diaza-Nazarov cyclization involving a 2,3-diaza-pentadienyl cation for the synthesis of polysubstituted pyrazoles

Functionally-rich pyrazoles in a cascade reaction from in situ generated hydrazones and acetophenones under aerobic conditions were synthesized through novel enamine–imino diaza-Nazarov 4π-electrocyclization which is supported by DFT calculations.

A practical protocol for the synthesis of bibenzyls via C(sp3)–H activation of methyl arenes under metal-free conditions

A variety of bibenzyl derivatives have been synthesized with excellent atom economy via C(sp³)–H–C(sp³)–H coupling of readily available methyl arenes using K₂S₂O₈ under metal-free and environmentally benign conditions.

Elemental sulfur mediated synthesis of benzoxazoles, benzothiazoles and quinoxalines via decarboxylative coupling of 2-hydroxy/mercapto/amino-anilines with cinnamic acids

A practical method has been developed for the synthesis of 2-benzylbenzoxazoles and 2-benzylbenzothiazoles using sulfur mediated decarboxylative coupling of cinnamic acids with 2-hydroxyanilines and 2-mercaptoanilines respectively.

Supramolecular Macrocyclic Pd(II) and Pt(II) Squares and Rectangles with Aryldithiolate Ligands and their Excellent Catalytic Activity in Suzuki C-C Coupling Reaction

Addition of 1,4-benezenedithiol and 4,4'-biphenyldithiol to M(OTf)2 (M = cis-[Pt(PEt3)2](2+) or cis-[Pd(dppe)](2+)) (dppe = 1,2-bis(diphenylphosphino)ethane) gave self-assembled tetranuclear complexes [M2{S(C6H4)nS}]2(OTf)4 (n = 1, 2). The same reaction with 1,4-benezenedimethanethiol yielded octanuclear supramolecular coordination complexes (SCC) [M2{SCH2C6H4CH2S}]4(OTf)8. These complexes were characterized by NMR, mass, and UV-vis spectroscopies, cyclic voltammetry, as well as density functional theory studies and represent the first examples of SCCs constructed by thiolate groups and square-planar metal ions. The rectangular shape of tetranuclear complexes and square shape of octanuclear complex are confirmed by single-crystal structures and computational studies. The palladium complexes showed excellent catalytic activity in Suzuki C-C cross-coupling reactions with high turnover numbers (2 × 10(7)), even with low catalyst loading.

Copper catalysed C–N bond formation via a sequential acylation and deacylation process: a novel strategy for the synthesis of benzanilides

An efficient oxidative amidation of aldehydes using acetanilides as amine component has been developed by copper catalysis. The approach is versatile and proceeds through sequential acylation and deacylation to afford benzanilides.