Synthesis Of Sulfoxides Research Articles

Two Schiff-base complexes of cadmium and manganese on modified MCM-41 as practical, recyclable and selective nanocatalysts for the synthesis of sulfoxides

Two Schiff-base complexes of cadmium and manganese on modified MCM-41 as practical, recyclable and selective nanocatalysts for the synthesis of sulfoxides

Oxidative Dehydrogenative Coupling of Thiols with Alkanes for the Synthesis of Sulfoxides.

An oxidative dehydrogenative coupling of thiols with alkanes via direct C(sp3)-H bond functionalization to form a new C-S bond and S═O double bond was developed. The present reaction features the use of readily available reagents and high step- and atom-efficiency, thus providing an efficient access to sulfoxides. A possible mechanism is proposed.

Synthesis, Characterization of Zirconia and Molybdenum Doped on Silica: Study their Catalytic Activity for Oxidation of Sulphides

To explore the structural, green methodology and thermal stability for synthesizing series of ternary mixed metal oxides were prepared by doping ZrO2 and MoO3 on SiO2 (ZMS) by sol-gel method. Catalysts were examined by XRD, FT-IR, XPS, Raman spectroscopy, temperature programmed desorption (TPD) and TEM techniques. Both oxides showed the high stability with nanocrystalline nature and the catalytic activity of synthesized ZMS catalyst were tested for oxidation of sulfides to sulfoxides at room temperature. Gas chromatography was used to analyze the products. A high selectivity obtained by nicely controlled a variation of catalyst amount as well as amounts of oxidant applied. Recycling experiments explained that the synthesized ZMS catalysts can be recycled many times without major loss of their activity. The catalytic system provided a number of advantages including clean, use of green solvent and easy handling strategy for the synthesis of sulfoxides at mild conditions.

A reductive Sandmeyer-type reaction for the synthesis of sulfoxides from anilines under photocatalysis

A reductive Sandmeyer-type sulfinylation reaction of aryldiazonium salts with sodium sulfinates is reported, affording a range of valuable sulfoxides in a radical substitution pathway.

Visible-light-induced sulfoxidation using chitosan-supported organic dyes photocatalyst

Heterogeneous photocatalysts are recognized as promising candidates for photoredox reactions owing to their environmental benignity and economic efficiency. However, various functionalized organic or inorganic materials are usually utilized as carriers while not considering their complex preparation procedures and the high costs. Moreover, the catalyst loadings are not given sufficient attention. Herein, a novel recyclable photocatalyst is developed by anchoring organic dyes on biomass-derived polymers through a facile ion-exchange process. It was applied for triggering photooxidation of sulfides using air as an environmentally benign oxidant. Results show that it is a highly effective photocatalyst for selective oxidation reactions to afford a wide assortment of valuable sulfoxides. The strategy is also applicable to the synthesis of sulfoxides from alkenes and thiols. The synthetic utility of the biomass-supported organic dyes photocatalysts, together with its recoverability, reusability, and simplified purification process, renders it promising for the transformation of organic chemicals into valuable complexes.

Asymmetric synthesis of sulfoxides by novel Baeyer-Villiger monooxygenase from Fusarium

In the chemical industry, the oxidation reaction is one of the essential reactions, although some oxidizing reagents are potentially explosive. Hence, the safe reaction catalyzed by monooxygenases, enzymes that can catalyze oxidation reactions using molecular oxygen in the air, becomes an attractive alternative as it promotes green and sustainable chemistry. Herein, sulfoxidation of alkyl aryl sulfides by a novel Baeyer-Villiger monooxygenase from a fungus, Fusarium sp. NBRC 109816 (FBVMO), was investigated. The effect of organic cosolvents was also examined using purified FBVMO, improving the activity by up to 247%. E. coli whole cell expressing FBVMO was used for the synthetic purpose, and various chiral sulfoxides were obtained successfully in up to 92% isolated yield and up to 99% ee (R).

A Sulfoxide Reagent for One‐Pot, Three‐Component Syntheses of Sulfoxides and Sulfinamides**

AbstractSulfoxides and sulfinamides represent versatile sulfur functional groups found in ligands, chiral auxiliaries, and bioactive molecules. Canonical two‐component syntheses, however, rely on substrates with a preinstalled C−S bond and impede efficient and modular access to these sulfur motifs. Herein is presented the application of an easily prepared, bench‐stable sulfoxide reagent for one‐pot, three‐component syntheses of sulfoxides and sulfinamides. The sulfoxide reagent donates the SO unit upon the reaction with a Grignard reagent (RMgX) as a sulfenate anion (RSO−). While subsequent trapping reactions of this key intermediate with carbon electrophiles provide sulfoxides, a range of tertiary, secondary, and primary sulfinamides can be prepared by substitution reactions with electrophilic amines. The syntheses of sulfinamide analogs of amide‐ and sulfonamide‐containing drugs illustrate the utility of the method for the rapid preparation of medicinally relevant molecules.

A Sulfoxide Reagent for One-Pot, Three-Component Syntheses of Sulfoxides and Sulfinamides.

Sulfoxides and sulfinamides represent versatile sulfur functional groups found in ligands, chiral auxiliaries, and bioactive molecules. Canonical two-component syntheses, however, rely on substrates with a preinstalled C-S bond and impede efficient and modular access to these sulfur motifs. Herein is presented the application of an easily prepared, bench-stable sulfoxide reagent for one-pot, three-component syntheses of sulfoxides and sulfinamides. The sulfoxide reagent donates the SO unit upon the reaction with a Grignard reagent (RMgX) as a sulfenate anion (RSO- ). While subsequent trapping reactions of this key intermediate with carbon electrophiles provide sulfoxides, a range of tertiary, secondary, and primary sulfinamides can be prepared by substitution reactions with electrophilic amines. The syntheses of sulfinamide analogs of amide- and sulfonamide-containing drugs illustrate the utility of the method for the rapid preparation of medicinally relevant molecules.

Organophotoredox-Catalyzed Sulfurization of Alkenes and Alkynes: Selective and Controlled Synthesis of Sulfoxides, β-Hydroxysulfoxides, and β-Keto Sulfides.

A visible-light organophotoredox-catalyzed sulfurization of alkenes and alkynes with aromatic and heteroaromatic thiols using eco-friendly air (O2) as the sole oxidant has been demonstrated. The established method delivers a novel, benign, and metal-free strategy for the difunctionalization of alkenes and alkynes using organophotoredox catalyst Eosin Y. The selective and controlled synthetic approach shows good substrate generality to afford sulfoxides, β-hydroxysulfoxides, and β-keto sulfides in high yield and excellent regioselectivity.

Synthesis of Enantioenriched Sulfoxides by an Oxidation-Reduction Enzymatic Cascade.

Chiral sulfoxides are versatile synthons and have gained a particular interest in asymmetric synthesis of active pharmaceutical and agrochemical ingredients. Herein, a linear oxidation-reduction bienzymatic cascade to synthesize chiral sulfoxides is reported. The extraordinarily stable and active vanadium-dependent chloroperoxidase from Curvularia inaequalis (CiVCPO) was used to oxidize sulfides into racemic sulfoxides, which were then converted to chiral sulfoxides by highly enantioselective methionine sulfoxide reductase A (MsrA) and B (MsrB) by kinetic resolution, respectively. The combinatorial cascade gave a broad range of structurally diverse sulfoxides with excellent optical purity (>99 % ee) with complementary chirality. The enzymatic cascade requires no NAD(P)H recycling, representing a facile method for chiral sulfoxide synthesis. Particularly, the envisioned enzymatic cascade not only allows CiVCPO to gain relevance in chiral sulfoxide synthesis, but also provides a powerful approach for (S)-sulfoxide synthesis; the latter case is significantly unexplored for heme-dependent peroxidases and peroxygenases.

Low‐Voltage‐Driven Electrochemical Aerobic Oxygenation with Flavin Catalysis: Chemoselective Synthesis of Sulfoxides from Sulfides

AbstractThe chemoselective electrochemical oxygenation of sulfides to sulfoxides is performed using a biomimetic flavin catalyst that enables the activation of molecular oxygen under a low cathode potential. Diverse functional groups, including alcohols, ketones, aldehydes, cyclopropane, carboxylic acids, pyridine, alkenes, and alkynes, are well tolerated under low‐voltage electrolytic conditions.magnified image

“Nonpolarity paving” in substrate tunnel of a Limnobacter sp. Phenylacetone monooxygenase for efficient single whole-cell synthesis of esomeprazole

Baeyer-Villiger monooxygenase (BVMO) mediated sulfoxidation is a sustainable approach for the synthesis of esomeprazole. In this work, a novel phenylacetone monooxygenase from Limnobacter sp. (LnPAMO) was found to have trace activity for synthesis of enantiopure esomeprazole. Through engineering in the substrate tunnel using a mutagenesis strategy called “nonpolarity paving” and some modifications in cofactor binding domains, a mutant harboring 15 mutations (LnPAMO Mu15) was obtained with 6.6 × 103-fold higher activity to convert omeprazole sulfide into esomeprazole. The activities of the mutant for synthesis of (S)-methyl phenyl sulfoxide and (S)-pantoprazole also increased much, indicating the versatility of the mutant for sulfoxide synthesis. Importantly, no over-oxidation byproduct omeprazole sulfone was detected in the sulfoxidation products by both mass spectrometry and HPLC analysis. Then NADP-dependent Burkholderia stabili formate dehydrogenase was ligated behind Mu15 along with a ribosome binding site sequence in pET-28a for co-expression. By single whole-cell of recombinant Escherichia coli BL21 coexpressing Mu15 and formate dehydrogenase, omeprazole sulfide was efficiently converted into esomeprazole without production of sulfone (16 g/L substrate, enantiomeric excess > 99.9% (S) and > 99% conversion) and the space–time-yield reached 1.67 g product/L/h.

Access to Sulfoxides under NHC/Photocatalysis via a Radical Pathway.

A photocatalyzed transformation from sulfinic acids to sulfoxides under visible-light irradiation in the presence of N-heterocyclic carbene is established. Various alkyl groups from four-substituted Hantzsch esters or Meyer nitriles are smoothly converted to the corresponding sulfoxides through a radical coupling pathway in the presence of 1,1-carbonyldiimidazole. This method allows sulfoxide synthesis to refrain from relying on the oxidation of sulfides and provides an alternative route for the preparation of sulfoxides.

Switchable Synthesis of Sulfoxides, Sulfones and Thiosulfonates through Selectfluor-Promoted Oxidation with H2O as O-Source

AbstractA practical and efficient protocol for the switchable synthesis of sulfoxides, sulfones, and thiosulfonates via Selectfluor-mediated oxidation of sulfides and thiols, respectively, at ambient temperature has been developed. All these organosulfur compounds can be prepared with nearly quantitative yields by applying eco-friendly H2O as O-source. The formation of sulfoxides and thiosulfonates takes only a few minutes (3–20 min). As suggested by the control experiments, the oxidation procedure might proceed through the fluorination of sulfide, nucleophilic addition with H2O, and elimination of hydrogen fluoride.

Catalytic sulfoxidation of sulphide to sulfoxide over cobalt and iron doped chromium oxide nanoparticle catalyst

Iron and cobalt-doped chromium oxide nanoparticles were synthesized by the co-precipitation method and calcined at 400 °C for 3 h. The obtained nanoparticles were characterized by various spectroscopic techniques like powder X-ray diffraction (PXRD), Fourier transforms infrared (FTIR), UV/visible spectroscopy, Field emission scanning electron spectroscopy (FESEM). The average particle size of synthesized nanoparticles was found in the range of 15–60 nm with a spherical shape. Result of the powder XRD pattern indicates the amorphous nature of the iron-doped chromium oxide nanoparticles. Furthermore, the application part of nanoparticles was studied as a catalyst for the synthesis of sulfoxide from sulphide. It was found that the catalyst convert sulfide into sulfoxide with H2O2, TBHP, and UHP as an oxidant and gave 97%, 95%, and 51% conversion respectively at 60 °C temperature in 10 h. Moreover, based on the time and temperature data, the iron-doped chromium oxide nanoparticles catalyst was shown the best result for sulfoxidation.

A sustainable photochemical aerobic sulfide oxidation: access to sulforaphane and modafinil.

Sulfoxide-containing molecules are an important class of compounds in the pharmaceutical industry and many efforts have been made to develop new and green protocols, targeting the chemoselective transformation of sulfides into sulfoxides. Photochemistry is a rapidly expanding research field employing light as the energy source. Photochemical aerobic processes possess additional advantages to photochemistry and may find applications in the chemical industries. Herein, a 370 nm catalyst-free aerobic protocol was developed, using 2-Me-THF as the green solvent. At the same time, two low-catalyst-loading anthraquinone-based processes (under a CFL lamp or 427 nm irradiation) in 2-Me-THF were developed. Furthermore, a broad range of substrates was tested. We also implemented our protocols towards the synthesis of the pharmaceutical active ingredients (APIs) sulforaphane and modafinil.

A POM-based porous supramolecular framework for efficient sulfide–sulfoxide transformations with a low molar O/S ratio

A porous supramolecular framework heterogeneously catalyzed the oxidative synthesis of sulfoxides and the detoxification of mustard gas simulants with a low molar O/S ratio.

Asymmetric Synthesis of Sulfoxides by Novel Baeyer-Villiger Monooxygenase from Fusarium

Asymmetric Synthesis of Sulfoxides by Novel Baeyer-Villiger Monooxygenase from Fusarium

Advances of Sulfenate Anions in Catalytic Asymmetric Synthesis of Sulfoxides.

In recent years, sulfenate anions as key intermediates in enantioselective synthesis have attracted considerable attention. Typically, development of novel synthetic methods to generate sulfenate anions allows for the preparation of various enantiopure sulfoxides, which are prevalently used as auxiliaries, ligands, organocatalysts, and biologically active compounds. This review presents the in situ preparation methods and the recent applications of sulfenate anions in catalytic asymmetric synthesis of chiral sulfoxides.

Switchable Synthesis of Sulfoxides and α-Alkoxy-β-ketothioethers Regulated by Temperature in a Selectfluor-Methanol System.

A switchable and benign protocol for chemoselective synthesis of sulfoxides and α-alkoxy-β-ketothioethers has been developed. It was determined that various thiophenols and alkenes/alkynes are compatible to realize the target compounds from a medium to a high yield by regulating the reaction temperature. In particular, methanol not only served as a solvent but also participated in the reaction process as a hydrogen donor. In this study, Selectfluor has been proved to be an efficient multifunctional reagent in the reaction system.