Deoxygenation Of Sulfoxides Research Articles

Deoxygenation of sulfoxides using D-camphorsulfonic acid as an efficient reducing agent under metal and additive-free conditions

Deoxygenation of sulfoxides using D-camphorsulfonic acid as an efficient reducing agent under metal and additive-free conditions

Triethyl amine as an effective reducing agent for sulfoxide deoxygenation.

Enabled by triethyl amine (Et3N) and thionyl chloride (SOCl2), an efficient and practical protocol for deoxygenation of sulfoxide to sulfide was developed. This new method features a wide range of substrate scope, including diaryl, dialkyl and aryl alkyl substituted sulfoxides. Detailed mechanistic investigations reveal the crucial role played by Et3N as an electron-donating reductant rather than a hydrogen-atom donor.

Hydrogenation of sulfoxides to sulfides mediated by incomplete cubane-type Mo3S4 clusters: synthetic applications and mechanistic insights

Homogeneous catalysts for the deoxygenation of sulfoxides to sulfides have not been widely explored. Herein, we report a green and efficient protocol for the catalytic hydrogenation of sulfoxides using an...

One-pot thermo-induced radical-radical oxidative cross-coupling for symmetrical dimeric thiadiazole monosulfide formation

The production of heterocyclic sulfide is the key building block in various applications, especially in the field of medicinal chemistry. Currently, heterocyclic sulfide was synthesized via deoxygenation of sulfoxide or cross coupling between sulfur sources and halogen compounds. However, these conventional methods suffer from drawbacks such as the use of toxic solvents, harsh reaction conditions, the requirement for transition metal catalysts, inert conditions, and the generation of toxic and corrosive halide-containing waste. In this study, a milder approach using hydrogen peroxide-mediated oxidative cross-coupling of 5-alkylsulfanyl-[1,3,4]thiadiazole-2-thiol successfully produces symmetrical dimeric thiadiazole monosulfide with an isolated yield of 73‒87 %. The molecular structure of bis(2-octylsulfanyl-[1,3,4]thiadiazolyl)-5,5′-sulfide was confirmed by X-ray crystal structure analysis. Interestingly, the formation of dimeric thiadiazole monosulfide undergoes a one-pot thermo-induced pathway. Density functional theory (DFT) indicates the formation of thiadiazole monosulfide is thermodynamically favorable through the cross-coupling reaction between thiadiazole thiyl radical and thiadiazole carbon-centered radical.

Sisal-derived acid-char molybdenum catalyst for reductive deoxygenation of sulfoxides

The deoxygenation of sulfoxides is a rather important reaction from both synthetic and biological points of view, due to the potential of sulfides as intermediates in a variety of processes. Homogenous Mo-based catalysts successfully perform the reduction of diphenyl sulfoxide to diphenyl sulfide with high yields but present the well-known limitations regarding recovery and recycling. Thus, in the present work, two new supported catalysts were prepared through the immobilization of molybdenum precursor species (dichlorodioxodi(aquo)molybdenum(VI) and sodium molybdate), onto a sisal-derived acid-char (S13.5), obtained from rope industry wastes by acid-mediated carbonization. The heterogeneous Mo-based materials were characterized by IR spectroscopy, elemental analysis, ICP, solid state NMR, XPS, and SEM, and were evaluated as catalysts for the reduction of sulfoxides to sulfides in the presence of phenylsilane as reducing agent under different reaction conditions. The influence of various experimental parameters, including reducing agent type and amount, solvent type, and acid promoter were investigated. Catalytic studies revealed that both catalysts deoxygenate sulfoxides at 120 °C in toluene solution with high yields (up to 97%). The MoO2Cl2 derived catalyst shown to be highly efficient in the reduction of diaryl, alkylaryl, dibenzyl, and dialkyl sulfoxides to the corresponding sulfoxides using phenylsilane as reductant and no need of acid promoter.

Revolutionizing regeneration of NADH and deoxygenation of sulfide: Harnessing visible light with SDG@TPP composites for powerful synthetic applications

Aqueous ascorbic acid splitting through photocatalysis is a potential method for turning solar energy into value-added compounds. As a result, converting solar light into green solar fine chemicals in an ecologically responsible and cost-effective manner remains a difficult issue. The solvothermal approach was used to effectively construct an SDG@TPP composite photocatalyst.To that end, we present here the synthesis and development of a sulfur-doped graphene (SDG)-based visible light active composite photocatalyst (SDG@TPP), in which SDG interacts with TPP (tetraphenyl porphyrin) through - stacking. Due to its high molar extinction coefficient and delayed recombination features, the newly manufactured SDG@TPP photocatalyst acts in a highly effective way, resulting in higher NADH regeneration (66.1 %) and sulfoxide deoxygenation than SDG photocatalyst. More importantly, a little quantity of TPP on the surface of SDG can efficiently stimulate photoelectron injection and improved photocatalytic activity. This research should shed light on how to create metal-free SDG@TPP composites with good solar energy conversion.

Visible light induced deoxygenation of sulfoxides with isopropanol

We report visible light induced deoxygenation of sulfoxides to sulfides catalyzed by anthraquinone under irradiation at 430–440 nm at room temperature employing cheap isopropanol as a green reducing agent.

1,2‐Bis(diphenylphosphino)ethane (dppe)/NBS: An Unprecedented Combination for Deoxygenation of Sulfoxides Under Mild Conditions

AbstractA novel, efficient and metal‐free strategy for the deoxygenation of sulfoxides to sulfides has been disclosed under mild conditions using dppe/NBS reagent system. Among several developed methods using phosphine based ligands, very few are convenient as most of them are confined to harsh reaction conditions, inseparable side products, moderate yields, and the use of costly and toxic reagents. The developed dppe/NBS promoted deoxygenation strategy tolerates a wide range of functional groups to afford good yields of desired sulfides.

Phosphorus-Alloying as a Powerful Method for Designing Highly Active and Durable Metal Nanoparticle Catalysts for the Deoxygenation of Sulfoxides: Ligand and Ensemble Effects of Phosphorus.

The modification of metal nanoparticles (NPs) by incorporating additional metals is a key technique for developing novel catalysts. However, the effects of incorporating nonmetals into metal NPs have not been widely explored, particularly in the field of organic synthesis. In this study, we demonstrate that phosphorus (P)-alloying significantly increases the activity of precious metal NPs for the deoxygenation of sulfoxides into sulfides. In particular, ruthenium phosphide NPs exhibit an excellent catalytic activity and high durability against sulfur-poisoning, outperforming conventional catalysts. Various sulfoxides, including drug intermediates, were deoxygenated to sulfides with excellent yields. Detailed investigations into the structure–activity relationship revealed that P-alloying plays a dual role: it establishes a ligand effect on the electron transfer from Ru to P, facilitating the production of active hydrogen species, and has an ensemble effect on the formation of the Ru–P bond, preventing strong coordination with sulfide products. These effects combine to increase the catalytic performance of ruthenium phosphide NPs. These results demonstrate that P-alloying is an efficient method to improve the metal NP catalysis for diverse organic synthesis.

CoCe/N–C hybrids constructed via Ce–O–Co solid solution for the deoxygenation of sulfoxide

CeO2-promoted Co–N–C hybrids were prepared by the strategy of solid solution construction for the deoxygenation of sulfoxide.

Indium‐Catalyzed Deoxygenation of Sulfoxides with Hydrosilanes

AbstractDescribed herein is that a novel InBr3/PhSiH3 reducing system in a 1,4‐dioxane solution smoothly and effectively undertook deoxygenation of a variety of sulfoxides leading to the facile preparation of sulfide derivatives. Also, it was demonstrated that the reducing system shows a higher reactivity towards sulfoxides than that towards commonly reducible functional groups, such as carboxylic acids, esters, amides, and sulfones.

Deoxygenation of Sulfoxides on Nano-Nickel Phosphide/Titania Catalyst

Deoxygenation of Sulfoxides on Nano-Nickel Phosphide/Titania Catalyst

Deoxygenation of Sulfoxides with Dimethylthiocarbamoyl Chloride in the Absence of Additional Solvent

Deoxygenation of Sulfoxides with Dimethylthiocarbamoyl Chloride in the Absence of Additional Solvent

Electrophilic Chlorine from Chlorosulfonium Salts: A Highly Chemoselective Reduction of Sulfoxides.

Herein, we describe a selective late-stage deoxygenation of sulfoxides based on a novel application of chlorosulfonium salts and demonstrate a new process using these species generated in situ from sulfoxides as the source of electrophilic chlorine. The use of highly nucleophilic 1,3,5-trimethoxybenzene (TMB) as the reducing agent is described for the first time and applied in the deoxygenation of simple and functionalized sulfoxides. The method is easy to handle, economic, suitable for gram-scale operations, and readily applied for poly-functionalized molecules, as demonstrated with more than 45 examples, including commercial medicines and analogues. We also report the results of competition experiments that define the more reactive sulfoxide and we present a mechanistic proposal based on substrate and product observations.

Photocatalytic Deoxygenation of Sulfoxides Using Visible Light: Mechanistic Investigations and Synthetic Applications.

The photocatalytic deoxygenation of sulfoxides to generate sulfides facilitated by either Ir[(dF(CF3)ppy)2(dtbbpy)]PF6 or fac-Ir(ppy)3 is reported. Mechanistic studies indicate that a radical chain mechanism operates, which proceeds via a phosphoranyl radical generated from a radical/polar crossover process. Initiation of the radical chain was found to proceed via two opposing photocatalytic quenching mechanisms, offering complementary reactivity. The mild nature of the radical deoxygenation process enables the reduction of a wide range of functionalized sulfoxides, including those containing acid-sensitive groups, in typically high isolated yields.

Nickel phosphide nanoalloy catalyst for the selective deoxygenation of sulfoxides to sulfides under ambient H2 pressure.

Exploring novel catalysis by less common, metal-non-metal nanoalloys is of great interest in organic synthesis. We herein report a titanium-dioxide-supported nickel phosphide nanoalloy (nano-Ni2P/TiO2) that exhibits high catalytic activity for the deoxygenation of sulfoxides. nano-Ni2P/TiO2 deoxygenated various sulfoxides to sulfides under 1 bar of H2, representing the first non-noble metal catalyst for sulfoxide deoxygenation under ambient H2 pressure. Spectroscopic analyses revealed that this high activity is due to cooperative catalysis by nano-Ni2P and TiO2.

Metal-free Reductive Deoxygenation of Sulfoxides by an Organosilicon Reductant, 1,1′-Bis(trimethylsilyl)-1H,1′H-4,4′-bipyridinylidene

A metal-free deoxygenation of sulfoxides to sulfides was established under mild conditions using a stoichiometric amount of 1,1′-bis(trimethylsilyl)-1H,1′H-4,4′-bipyridinylidene (1) as a reducing r...

Photocatalytic Deoxygenation of Sulfoxides and Pyridine N-Oxides

Photocatalytic Deoxygenation of Sulfoxides and Pyridine N-Oxides

Mild Deoxygenation of Sulfoxides over Plasmonic Molybdenum Oxide Hybrid with Dramatic Activity Enhancement under Visible Light.

Harvesting solar light to boost commercially important organic synthesis still remains a challenge. Coupling of conventional noble metal catalysts with plasmonic oxide materials which exhibit intense plasmon absorption in the visible light region is a promising option for efficient solar energy utilization in catalysis. Herein, we for the first time demonstrate that plasmonic hydrogen molybdenum bronze coupled with Pt nanoparticles (Pt/H xMoO3- y) shows a high catalytic performance in the deoxygenation of sulfoxides with 1 atm of H2 at room temperature, with dramatic activity enhancement under visible light irradiation relative to dark conditions. The plasmonic molybdenum oxide hybrids with strong plasmon resonance peaks pinning at around 556 nm are obtained via a facile H-spillover process. Pt/H xMoO3- y hybrid provides excellent selectivity for the deoxygenation of various sulfoxides as well as pyridine N-oxides, in which drastically improved catalytic efficiencies are obtained under the irradiation of visible light. Comprehensive analyses reveal that oxygen vacancies massively introduced via a H-spillover process are the main active sites, and the reversible redox property of Mo atoms and strong plasmonic absorption play key roles in this reaction. The catalytic system works under extremely mild conditions and can boost the reaction by the assistance of visible light, offering an ultimately greener protocol to produce sulfides from sulfoxides. Our findings may open up a new strategy for designing plasmon-based catalytic systems that can harness visible light efficiently.

B(C6F5)3-Catalyzed Reduction of Sulfoxides and Sulfones to Sulfides with Hydrosilanes

B(C6F5)3 is shown to catalyze the deoxygenation of sulfoxides and sulfones to the corresponding sulfides with Et3SiH as the stoichiometric hydride source. While the method is limited in terms of functional group tolerance, it is applicable to the reduction of alkyl/aryl-, aryl/aryl-, and alkyl/alkyl-substituted sulfoxides, including the benzyl/benzyl-substituted derivative. The same protocol converts alkyl/aryl- but not aryl/aryl-substituted sulfones into sulfides.