Transition-Metal-Free Diarylannulated Sulfide and Selenide Construction via Radical/Anion-Mediated Sulfur–Iodine and Selenium–Iodine Exchange

Versatile Dibenzothio[seleno]phenes via Hexadehydro-Diels-Alder Domino Cyclization

A facile strategy to synthesize highly substituted dibenzoselenophenes and dibenzothiophenes by a domino hexadehydro-Diels–Alder reaction is reported in this article. The formation of three new C–C bonds, one new Caryl–Se/Caryl–S bond, and C–H σ-bond migration via one-pot multiterminal cycloaddition reactions were involved in over three transformations. The target tetracyclic compounds were prepared from tetraynes with a triphenylphosphine selenide or triphenylphosphine sulfide. This reaction played a pivotal role in constructing natural thio[seleno]phene cores, which were highly substituted, and is a robust method for producing fused heterocycles.

Black Phosphorus: An Effective Feedstock for the Synthesis of Phosphorus-Based Chemicals

We propose and demonstrate the novel concept of synthesizing organophosphorus compounds directly from black phosphorus (BP) nanoparticles as the feedstock. Compounds such as alkyl phosphines, alkyl phosphine oxides, phosphine sulfide, and hexafluorophosphate anion are prepared with good isolation yields under mild conditions. Selective synthesis of primary, secondary, and tertiary organophosphorus compounds is also demonstrated utilizing this one-pot approach. Reaction mechanisms are proposed and discussed. Compared with traditional white phosphorus (P4)-based methods, the new synthetic concept and process utilizing elemental phosphorus are more efficient and environmentally friendly.

Copper-catalyzed synthesis of 2-acylbenzo[b]thiophenes from 3-(2-iodophenyl)-1-arylpropan-1-ones and potassium sulfide under aerobic conditions

A method was developed for the synthesis of 2-acylbenzo[b]thiophenes via a copper-catalyzed sulfuration of 3-(2-iodophenyl)-1-arylpropan-1-ones with K2S under aerobic conditions. Mechanistically, this procedure was proved to involve the formation of a dihydrobenzo[b]thiophene intermediate.

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.

Using SeO2 as a selenium source to make RSe-substituted aniline and imidazo[1,2-a]pyridine derivatives

A mild and practical method is developed for the synthesis of ArSe-substituted aniline and imidazo[1,2-a]pyridine derivatives using SeO₂ as a selenium agent.

Ring-opening/annulation reaction of cyclopropyl ethanols: concise access to thiophene aldehydes via C–S bond formation

The synthesis of thiophene aldehydes from easily available cyclopropyl ethanol derivatives and potassium sulfide has been developed.

Catalyst- and additive-free annulation/aromatization leading to benzothiazoles and naphthothiazoles

Catalyst- and additive-free three-component annulation/aromatization enable a highly efficient entry to naphtho[1,2-d]thiazoles and benzo[d]thiazoles.

Three-component bis-heterocycliation for synthesis of 2-aminobenzo[4,5]thieno[3,2-d]thiazoles

A cooperative base system has been developed for the novel three-component synthesis of 2-aminobenzo[4,5]thieno[3,2-d]thiazoles via bis-heterocyclization of methylketoxime acetates.

The role of polysulfide dianions and radical anions in the chemical, physical and biological sciences, including sulfur-based batteries

Polysulfide dianions and radical anions play a crucial role in biological chemistry, geochemical processes, alkali metal–sulfur batteries, organic syntheses, coordination chemistry, and materials sciences.

Synthesis of α-Keto Thioamides by Metal-Free C═C Bond Cleavage in Enaminones Using Elemental Sulfur

An unprecedented method for cleaving the C═C bond in N, N-disubstituted enaminones in the presence of elemental sulfur and N, N-dimethyl-4-aminopyridine is disclosed. Without using any metal catalyst or additive, the cascade functionalization of both C═C and C-H bonds takes place to enable the formation of new C═S and C-N bonds, thus providing a facile and practical method for the synthesis of N, N-disubstituted α-keto thioamides.

Transition-Metal-Free Sulfuration/Annulation of Alkenes: Economical Access to Thiophenes Enabled by the Cleavage of Multiple C-H Bonds

A novel, atom economical, and transition-metal-free strategy for the synthesis of thiophenes from substituted buta-1-enes with potassium sulfide has been presented. The reaction achieves double C-S bond formations via cleavage of multiple C-H bonds and provides an efficient approach to access various functionalized thiophenes. Moreover, the strategy can also be used for the synthesis of thiophenes from 1,4-diaryl-1,3-dienes. Mechanistically, DMSO plays a role of oxidant and S₃^•- in situ generated from K₂S is involved.

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

Most of the polyvalent organoiodine compounds derive from iodoarenes, which are released in stoichiometric amounts in any reaction mediated by λ3- or λ5-iodanes. In parallel to the development of solid-supported reagents or reactions catalytic in iodine, a third strategy has emerged to address this issue in terms of sustainability. The atom-economy of transformations involving stoichiometric amounts of λ3- or λ5-iodanes, thus, has been improved by designing tandem reactions that allows for incorporating the aryl motif into the products through a subsequent one-pot nucleophilic addition or catalytic coupling reaction. This review summarizes the main achievements reported in this area.

A Pd-catalyzed optional approach for the synthesis of dibenzothiophenes

A direct and practical approach for the construction of DBTs was developed via a Pd-catalyzed tandem reaction, in which commercially available o-bromo-iodobenzenes combined with benzene thiols or iodobenzenes combined with o-bromo-benzene thiols were applied. These two approaches will provide an alternative for the synthesis of DBT derivatives.

Fused multifunctionalized dibenzoselenophenes from tetraynes

The facile synthesis of fused multifunctionalized dibenzoselenophenes by a one-pot-three-step cascade hexadehydro-Diels-Alder reaction of tetraynes is reported. The overall transformation involves the formation of four new C-C bonds and one new C_aryl-Se bond and C-H activation via both intramolecular cyclization and intermolecular free radical reactions.

Green carbon disulfide surrogateviaa combination of potassium sulfide and chloroform for benzothiazine-thione and benzothiazole-thione construction

An efficient and green carbon disulfide surrogateviafacile combination of potassium sulfide and chloroform has been developed.

Photocatalytic acylarylation of unactivated alkenes with diaryliodonium salts toward indanones and related compounds

A photocatalytic acylarylation of unactivated alkenes using diaryliodonium salts is described, giving 2-benzyl indanones and related compounds in promising yields with excellent diastereoselectivity.

Direct thiolation of aza-heteroaromatic N-oxides with disulfides via copper-catalyzed regioselective C–H bond activation

A novel and efficient thiolation reaction of aza-heteroaromatic N-oxides with disulfides via copper catalyzed C–H activation has been developed.

Elemental sulfur accelerated the reactivity of the 3-position of indole for the construction of chromeno[2,3-b]indoles

Elemental sulfur not only acted as an additional oxidant but also facilitated the reactivity of the 3-position of indole to construct chromeno[2,3-b]indoles.

Construction of Functionalized Annulated Sulfone via SO2/I Exchange of Cyclic Diaryliodonium Salts

A straightforward protocol for diarylannulated sulfone construction is efficiently established via SO₂/I exchange of iodonium(III) salts. Readily available inorganic Na₂S₂O₅ was served as a safe and convenient SO₂ surrogate. Diverse functionalized diarylannulated sulfones were smoothly achieved in good to excellent yields with great functional group compatibility. Organic light emitting diodes (OLEDs) material molecules were subsequently established via this method in gram scale. The unsymmetrical conjugated systems with donor-acceptor groups and π-conjugation bridges motifs, which substantially communicate electron mobility in semiconductor material molecules, were successfully afforded under the facile conditions of the exchange strategy.

Synthesis of Functionalized Biaryls and Poly(hetero)aryl Containing Medium-Sized Lactones with Cyclic Diaryliodonium Salts

A novel one-pot procedure is described for the transition-metal catalyzed sequential difunctionalization of diaryliodonium reagents. Reaction of commercially available anthranilic acid derivatives with readily available cyclic diaryliodonium salts followed by a Sonogashira coupling afforded various alkyne substituted biaryls in good to excellent yields. The functionalized biaryls were then utilized for the rapid and efficient one-pot synthesis of novel poly(hetero)aryl containing 10-membered lactones which are potential G-quadruplex binders and telomerase inhibitors.

Thiocarbonyl Surrogate via Combination of Sulfur and Chloroform for Thiocarbamide and Oxazolidinethione Construction

An efficient and practical thiocarbonyl surrogate via combination of sulfur and chloroform has been developed. A variety of thiocarbamides and oxazolidinethiones have been established, including chiral thiourea catalysts and chiral oxazolidinethione auxiliaries with high selectivity. Meanwhile, pesticides Diafenthiuron (an acaricide), ANTU (a rodenticide), and Chloromethiuron (an insecticide) were practically synthesized through this method in gram scale. Dicholorocarbene, as the key intermediate, was further confirmed via a carbene-trapping control experiment.

Oxidative dual C–H thiolation of imidazopyridines with ethers or alkanes using elemental sulphur

Dual C–H thiolation reactions using elemental sulphur remain a challenge.

Cu(ii)-catalyzed sulfide construction: both aryl groups utilization of intermolecular and intramolecular diaryliodonium salt

A sulfur–iodine exchange strategy was developed that utilized both aryl groups of diaryliodonium salt employed in intermolecular and intramolecular reactions.