Recent advances in the application of bromodimethylsulfonium bromide (BDMS) in organic synthesis

Solvent-controlled halohydroxylation or C3-C2 coupling of pyridinium salts through an interrupted dearomative reduction

Herein, we report an efficient and easily operable method to halohydroxylate pyridiniums through an interrupted dearomative reduction strategy. In this process, we make the most of the halide anion from the pyridinium salts by performing the reaction in DMSO without the need of external HX added. Notably, by changing the solvents from DMSO into Et2O, the bimolecular C3-C2 coupling occurs successfully.

Glycosylation of n-pentenyl glycosides using bromodiethylsulfonium salt as an activator: interception of the glycosyl intermediate by chloride ion transfer

Utilization of n-pentenyl glycosides (NPGs) in modern carbohydrate synthesis may be hindered by their sluggish activation, which results from reversible halogenation and cyclization processes. Bromodiethylsulfonium bromopentachloroantimonate (BDSB) has been previously shown to be a powerful brominating agent for the cation-π polyene cyclization of less reactive and electron-poor polyenes. This study demonstrates the activation of NPGs using BDSB as a powerful brominating agent. BDSB effectively activates the terminal olefins of NPGs and the reaction proceeds through 5-exo-tet cyclization, offering a rapid and mild approach for glycosylation with a wide range of glycosyl donors, including n-pentenyl mannoside, n-pentenyl galactoside, and n-pentenyl glucoside. The success of this approach derives from the chloride ion transfer from the nonnucleophilic SbCl5Br anion to the glycosyl intermediate, which disrupts the equilibrium and produces a glycosyl chloride intermediate that is smoothly converted to 22 coupling products, with yields ranging from moderate to excellent (49-100%). The β-selective glycosylation is accomplished when employing NPGs equipped with a neighboring participating group. The practicality of the BDSB-activated glycosylation is demonstrated by a gram-scale synthesis. This study showcases BDSB as a potent activator for NPG glycosylation through the interception of a glycosyl intermediate that diminishes the equilibration during halogenation and 5-exo-tet cyclization.

1,2-Fluorosulfenylation of unactivated alkenes with thiols and a fluoride source promoted by bromodimethylsulfonium bromide

A practical method that enables the fluorosulfenylation of unactivated alkenes processed directly with thiols and fluoride salts is presented. Good to excellent efficiencies and functional group tolerance are observed for both alkene substrates and thiols. The procedure also allows the use of gaseous ethylene as a two-carbon building block for β-fluoro thioether products.

Efficient Green Synthesis, Anticancer Activity, and Molecular Docking Studies of Indolemethanes Using a Bioglycerol-Based Carbon Sulfonic Acid Catalyst

Indolemethane derivatives are significant molecules in the study of N-heterocyclic chemistry. Herein, we designed and developed a highly efficient green synthesis of indolemethane compounds using a recyclable biodegradable glycerol-based carbon solid acid catalyst under solvent-free conditions at room temperature for 5 min with excellent yields. The synthesized compounds were subjected to cytotoxic activity against prostate (DU145), hepatocellular carcinoma (HepG2), and melanoma (B16) cell lines. The highest cytotoxicity effects were found with 1k (1.09 μM) and 1c (2.02 μM) against DU145, followed by 1a, 1d, 1f, 1n, and 1m between 5.10 and 8.18 μM concentrations. The anticancer activity is validated using molecular docking simulations, and comparing binding energies with the standard drug doxorubicin suggests that the title compounds are well fitted into the active site pocket of the target molecules..

Regiodivergent sulfonylation of terminal olefins via dearomative rearrangement

Sulfones are fascinating and highly used functional groups, but current syntheses still have limitations. Here, a regiodivergent transition metal-free approach towards sulfones [(E)-allylic sulfones and α-sulfonyl-methyl styrenes] is reported. The method employs commercially available olefins, bases, additives, solvents, and sodium sulfinates (RSO2Na) and produces adducts in good yields. Considering that up to 4 reactions (bromination, dearomative rearrangement, E2, and SN2) are happening, this approach is very efficient. The structures of key adducts were confirmed by X-ray crystallography.

A theoretical study on the proton affinity of sulfur ylides

The proton affinities of sulfoxide ylides, carbonyl ylides, allyl ylides, benzenyl ylides and heterocyclic ylides with typical substituents were investigated using the SOGGA11-X functional.

Redox-Divergent Construction of (Dihydro)thiophenes with DMSO

Thiophene-based rings are one of the most widely used building blocks for the synthesis of sulfur-containing molecules. Inspired by the redox diversity of these features in nature, we demonstrate herein a redox-divergent construction of dihydrothiophenes, thiophenes, and bromothiophenes from the respective readily available allylic alcohols, dimethyl sulfoxide (DMSO), and HBr. The redox-divergent selectivity could be manipulated mainly by controlling the dosage of DMSO and HBr. Mechanistic studies suggest that DMSO simultaneously acts as an oxidant and a sulfur donor. The synthetic potentials of the products as platform molecules were also demonstrated by various derivatizations, including the preparation of bioactive and functional molecules.

Nucleophilic halo-Michael addition under Lewis-base activation

A simple and general conjugate nucleophilic halogenation is presented. The THTO/halosilane combination has shown the ability to act as a nucleophilic halide source in the conjugate addition to a variety of Michael acceptors. In addition, a straightforward diastereoselective halogen installation using α,β-unsaturated acyloxazolidinones as platforms has been developed.

Structure-based design of human immuno- and constitutive proteasomes inhibitors

Starting from the X-ray structure of our previous tripeptidic linear mimics of TMC-95A in complex with yeast 20S proteasome, we introduced new structural features to induce a differential inhibition between human constitutive and immunoproteasome 20S particles. Libraries of 24 tripeptidic and 6 dipeptidic derivatives were synthesized. The optimized preparation of 3-hydroxyoxindolyl alanine residues from tryptophan and their incorporation in peptides were described. Several potent inhibitors of human constitutive proteasome and immunoproteasome acting at the nanomolar level (IC₅₀ = 7.1 nM against the chymotrypsin-like activity for the best inhibitor) were obtained. A cytotoxic effect at the submicromolar level was observed against 6 human cancer cell lines.

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

Bromination is one of the most important transformations in organic synthesis and can be carried out using bromine and many other bromo compounds. Use of molecular bromine in organic synthesis is well-known. However, due to the hazardous nature of bromine, enormous growth has been witnessed in the past several decades for the development of solid bromine carriers. This review outlines the use of bromine and different bromo-organic compounds in organic synthesis. The applications of bromine, a total of 107 bromo-organic compounds, 11 other brominating agents, and a few natural bromine sources were incorporated. The scope of these reagents for various organic transformations such as bromination, cohalogenation, oxidation, cyclization, ring-opening reactions, substitution, rearrangement, hydrolysis, catalysis, etc. has been described briefly to highlight important aspects of the bromo-organic compounds in organic synthesis.

The catalyst free synthesis of α-fluorinated aroylacyl imides

A convenient catalyst free one pot method to synthesize α-fluorinated aroylacyl imides with very good yields utilizing inexpensive reagents such as NaF and DMSO.

Bromination of olefins with HBr and DMSO

A simple and inexpensive methodology is reported for the conversion of alkenes to 1,2-dibromo alkanes via oxidative bromination using HBr paired with dimethyl sulfoxide, which serves as the oxidant as well as cosolvent. The substrate scope includes 21 olefins brominated in good to excellent yields. Three of six styrene derivatives yielded bromohydrins under the reaction conditions.

A direct approach for the expedient synthesis of unsymmetrical ethers by employing bromodimethylsulfonium bromide (BDMS) mediated C–S bond cleavage of naphthalene-2-ol sulfides

Synthesis of unsymmetrical ether derivatives using 1-(aryl(alkyl/arylthio)methyl)-naphthalene-2-ol and alcohols in the presence of bromodimethylsulfonium bromide (BDMS).

Synthesis of dimethyl aryl acylsulfonium bromides from aryl methyl ketones in a DMSO-HBr system

A new, simplified method for the synthesis of dimethyl aryl acylsulfonium salts has been developed. A series of dimethyl aryl acylsulfonium bromides were prepared by the reaction of aryl methyl ketones with hydrobromic acid and dimethylsulfoxide (DMSO). This sulfonium salt confirms that bromine production and the bromination reaction take place in the DMSO-HBr oxidation system. What’s more, it is also a key intermediate for the synthesis of arylglyoxals.