Allylic Sulfones Research Articles

Photoinduced Pd-Catalyzed Direct Sulfonylation of Allylic C-H Bonds.

Allylic sulfones are valuable motifs due to their medicinal and biological significance and their versatile chemical reactivities. While direct allylic C-H sulfonylation represents a straightforward and desirable approach, these methods are primarily restricted to terminal alkenes, leaving the engagement of the internal counterparts a formidable challenge. Herein we report a photocatalytic approach that accommodates both cyclic and acyclic internal alkenes with diverse substitution patterns and electronic properties. Importantly, the obtained allylic sulfones can be readily diversified into a wide range of products, thus enabling formal alkene transposition and all-carbon quaternary center formation through the sequential C-H functionalization.

Photoinduced Pd‐Catalyzed Direct Sulfonylation of Allylic C−H Bonds

AbstractAllylic sulfones are valuable motifs due to their medicinal and biological significance and their versatile chemical reactivities. While direct allylic C−H sulfonylation represents a straightforward and desirable approach, these methods are primarily restricted to terminal alkenes, leaving the engagement of the internal counterparts a formidable challenge. Herein we report a photocatalytic approach that accommodates both cyclic and acyclic internal alkenes with diverse substitution patterns and electronic properties. Importantly, the obtained allylic sulfones can be readily diversified into a wide range of products, thus enabling formal alkene transposition and all‐carbon quaternary center formation through the sequential C−H functionalization.

Nickel‐Catalyzed Reductive Cross‐Coupling of α–Trifluoromethylated Alkyl Electrophiles and Allylic Sulfones

AbstractFluorinated motifs are commonly found in drugs and agrochemicals. The inclusion of fluorine‐containing motifs in drug candidates during lead optimization has become a valuable strategy in pharmaceutical research and development. Significant research efforts have been dedicated to synthesizing molecules with a trifluoromethyl (CF3−) group on a stereogenic carbon. Herein, we disclose a mild and efficient nickel‐catalyzed reductive cross‐coupling between α–trifluoromethyl alkyl bromides and allylic sulfones, enabling the efficient synthesis of α–trifluoromethyl homoallylic alkanes. This reaction featuring base‐free, mild conditions, a broad substrate scope, and high functional group tolerance. The synthetic versatility of this approach is further underscored by its successful application in the late‐stage functionalization of a range of drug molecules. Our preliminary mechanistic study suggests that this allylation process operates through a radical intermediate.

Photocatalytic Aldehyde Allylation for Site‐Specific DNA Functionalization

Comprehensive SummaryEnhancing the DNA toolbox with innovative photochemical reactions is pivotal for advancing nucleic acid‐based technologies. Aldehyde groups, versatile bioorthogonal handles for imine formation under acidic conditions, are particularly valuable due to their roles in nucleic acid epigenetics. Here, we present the first photocatalytic on‐DNA aldehyde allylation, enabling precise DNA functionalization under mild, neutral aqueous conditions. Our approach utilizes a photocatalytic polarity‐reversal reaction between DNA‐conjugated benzaldehydes and allyl sulfones. This reaction demonstrates exceptional chemoselectivity while preserving DNA integrity. By varying allyl sulfones, we achieve site‐specific labeling of non‐native DNA with the aldehyde group and cross‐linking with DNA‐bearing allyl sulfones. Furthermore, our method facilitates selective labeling and pull‐down enrichment of 5‐formylpyrimidine nucleotides among complex cellular DNA. This photocatalytic on‐DNA aldehyde transformation expands the limited bioorthogonal photochemical toolboxes, providing novel avenues for functionalizing both non‐native and native aldehyde modifications on DNA.

Electrochemical Synthesis of Vinyl, Alkyl, and Allyl Sulfones from Sodium Sulfinates and Olefins.

An electrochemical synthesis of vinyl, alkyl, and allyl sulfones using sodium sulfinates and olefins was reported. This method uses direct current to pass through an undivided cell equipped with graphite carbon electrodes, and a series of diverse sulfone compounds can be synthesized at room temperature in high yields.

Easily water soluble cellulose-based fluorescent probes for the detection of 4-nitrophenol

Cellulose, an abundantly available natural polymer, is generally insoluble in water or common organic solvents. In this study, fluorescent probes based on cellulose were fabricated, rendering them soluble in H2O and capable of selectively recognizing 4-nitrophenol (4-NP). Firstly, the modified cellulose with -Cl was prepared by the substitution reaction of –OH and SOCl2 on cellulose. Secondly, the reversible addition-fragmentation chain transfer (RAFT) reagent FNT with –NO2 and –CHO was obtained by reacting p-nitrophenylthiophenol with p-chloromethyl benzaldehyde. It was then reacted with 2,4-dimethylpyrrole to obtain a fluoroboronodipyrrole fluorescent RAFT reagent BNT with –NO2, followed by the reduction of –NO2 to –NH2 to obtain ABT. RAFT polymerization was conducted using reagent ABT with sodium vinyl sulfonate (SVS), sodium p-styrene sulfonate (SSS), sodium allyl sulfonate (SAS) in DMF. In the polymerization process, azobisisobutyronitrile (AIBN) was used as the initiator, yielded polymers with superior water solubility. Finally, three cellulose based fluorescent probes were prepared by substitutional reaction between -Cl on cellulose and –NH2 on the as-prepared polymers. The solubility of the probes was much higher than that of the original cellulose, and it can be served as macromolecular probes for the detection of 4-NP, and applied in environmental systems.

Palladium-Catalyzed Ligand-Enabled Cyclization of Substituted Aliphatic Carboxylic Acids with Allylic Electrophiles.

A palladium-catalyzed cyclization of the β-C(sp3)-H bond of aliphatic carboxylic acids with allylic electrophiles providing five-membered γ-lactones in good to excellent yields is demonstrated. An acetyl-protected aminoethyl phenyl thioether ligand is used to promote the C-H activation reaction. A diverse range of allylic electrophiles such as allyl alcohols, allyl acetates, allyl sulfones, allyl phosphonate, allyl amine, and allyl ester have been utilized for this reaction. A feasible reaction mechanism has been proposed to account for the present cyclization reaction.

Polymerizable alkyl 2-(tosylmethyl)acrylates: Highly efficient addition-fragmentation chain transfer agents for the development of low shrinkage dental composites

One of the major drawbacks for restorative dentistry is the polymerization shrinkage and the consequential shrinkage stress in methacrylate-based dental composites. An efficient way to reduce shrinkage stress is the incorporation of addition fragmentation chain transfer agents (AFCT agents). In this contribution, five novel polymerizable allyl sulfones were synthesized in four to five steps. A photo-DSC study was carried out in order to evaluate the influence of the addition of each AFCT agent on the polymerization rate of a dimethacrylate-based monomer mixture. The glass transition temperature (Tg) of the resulting networks was measured using DMTA. Dental composites based on these new chain transfer agents (CTAs) were prepared. A combination of camphorquinone, ethyl 4-(dimethylamino)benzoate and bis-(4-t-butylphenyl)-iodonium hexafluorophosphate was selected as photoinitiator system. Low shrinkage force values, suitable ambient light working time and excellent mechanical properties were obtained for all CTA based materials. Composites based on three of the synthesized CTAs even exhibited higher flexural modulus than the corresponding CTA-free material. Furthermore, a significant reduction of unreacted CTA leaching was found if a polymerizable moiety was introduced in the CTA structure. Hence, the incorporation of polymerizable allyl sulfones in dental composites is a promising strategy to obtain low shrinkage materials exhibiting improved biocompatibility.

Pd-Catalyzed Aerobic Synthesis of Allylic Sulfones from Allylic Alcohols and Sulfonyl Hydrazines in Water.

A mild and green synthesis of allylic sulfones from allylic alcohols and sulfonyl hydrazines was developed in water media. The simple and commercially available Pd(PPh3)4 is used as the best catalyst, and the reaction can proceed smoothly at 40 °C under air. This new method does not require the common nitrogen protection and organic media, and can be readily scaled up in gram scale, showing the good practicality value.

Cover Feature: Synthesis of Diverse Allylic Sulfone Derivatives via Sequential Hydroalkoxylation of 1,3‐Enynes (Chem. Eur. J. 42/2024)

Cover Feature: Synthesis of Diverse Allylic Sulfone Derivatives via Sequential Hydroalkoxylation of 1,3‐Enynes (Chem. Eur. J. 42/2024)

Synthesis of Diverse Allylic Sulfone Derivatives via Sequential Hydroalkoxylation of 1,3-Enynes.

A first metal-free protocol for the synthesis of allylic sulfones featuring aldehyde functionality at the δ-position has been reported. The formation of structurally complex δ,δ-dimethoxy allylic sulfones is enabled by the direct nucleophilic attack of methoxide onto the sulfone-containing 1,3-enynes. The present approach allows facile installation of acetal groups within the allylic sulfone scaffold, providing versatile platforms for further functionalization and drug development.

Enantioselective Synthesis of Allylic Sulfones via Rhodium-Catalyzed Direct Hydrosulfonylation of Allenes and Alkynes.

A highly regio- and enantioselective hydrosulfonylation using commercially available sodium sulfinates is reported, providing the first direct asymmetric rhodium-catalyzed hydrosulfonylation of allenes/alkynes to synthesize chiral allylic sulfones. Ligand screening studies demonstrated the indispensable role of the C1-symmetric P,N-ligand (Rax,S,S)-StackPhim for achieving both high regioselecitivity (>20:1) and enantioselectivity (up to 97% ee). Notably, the operationally simple method and mild conditions allow for the rapid preparation of chiral allylic sulfones with a wide scope of functional groups. Moreover, the use of sodium tert-butyldimethylsilyloxymethanesulfinate enables the collective synthesis of various chiral sulfone derivatives after simple transformations of the protected hydroxymethyl product.

Photoswitched Stereodivergent Synthesis of Allylic Sulfones.

The present Letter demonstrates a photoswitched stereodivergent synthesis of allylic sulfones from sodium sulfinates, triphenylvinylphosphonium chloride, and (hetero)aromatic aldehydes in a single step. Mechanistically, cis-allylic sulfones, generated from the unstabilized ylide intermediates and aldehydes in situ, could be finally converted to trans-allylic sulfones via photochemical isomerization in the presence of a catalytic amount of bis(2-thienyl) ketone.

Visible-Light Induced Radical Addition-Elimination Reaction for Constructing Allylic Sulfones from Sulfonyl Chlorides and Allyl Bromides.

Allyl sulfones are commonly present in bioactive compounds and organic building blocks. This work introduces a photocatalytic radical addition-elimination reaction involving readily accessible sulfonyl chlorides and allyl bromides. It delivers structurally diverse allylic sulfones in moderate to excellent yields, showcasing a high tolerance to functional groups. Notably, this method operates under mild reaction conditions without the need for oxidants, stoichiometric reducing metals, or additives.

Water Soluble, Ionically Generated Thiopolymers

AbstractSodium allyl sulfonate (SAS) is a surfactant molecule that has occasional use as a monomer for the formation of functional polymers. A polymerization method is detailed herein, whereby it is demonstrated that the positioning of the individual functional groups can allow for the removal of protons adjacent to a sulfonate position before reaction with an electrophilic center to generate a polymeric material. In this case, sodium polysulfides are applied to promote the formation of a sulfur polymer using a mild synthesis that poses significant safety and energy benefits when compared to other methods of sulfur polymer generation, for example, inverse vulcanization. The polymer product that forms is demonstrated to retain all starting functionalities. Poly‐S‐SAS polymer also demonstrates impressive properties for application as a desiccant with a sorption maximum of 345 w/w % water, or as a flocculant material capable of removing up to 87% of different metals from low ppm solutions rapidly.

Nickel-Catalyzed Suzuki-Miyaura Coupling in Water for the Synthesis of 2-Aryl Allyl Phosphonates and Sulfones.

An operationally simple and green protocol using a NiSO4·6H2O/cationic 2,2'-bipyridyl ligand system as a water-soluble catalyst for the coupling of arylboronic acids with (2-haloallyl)phosphonates and (2-haloallyl)sulfones in water under air was developed. The reaction was performed at 120 °C with arylboronic acids (2 mmol) and (2-haloallyl)phosphonates or sulfones (1 mmol) in the presence of 5 mol % of the Ni catalytic system in a basic aqueous solution for 1 h, giving the corresponding 2-aryl allyl phosphonates or sulfones in good to excellent yields. This reaction features the use of an abundant transition metal as a catalyst in water and exhibits high functional group tolerance, rendering it an eco-friendly procedure.

Neutral nickel-catalyzed dehydrosulfonylation of unactivated allylic alcohols under mild conditions.

Allyl sulfones are important sulfur-containing compounds that have widespread applications in organic synthesis, medicinal chemistry and materials science. Herein, nickel-catalysed dehydrosulfonylation of unactivated allyl alcohols with aryl sulfonyl hydrazides without additional active agents under mild conditions was developed. A variety of functional allyl sulfones could be efficiently synthesized in the presence of air-stable Ni(acac)2 as the catalyst and 1,1'-bis(diphenylphosphino)ferrocene (DPPF) as the ligand.

Rh-catalyzed asymmetric hydrogenation of allylic sulfones for synthesis of chiral β-ester sulfones

The highly enantioselective hydrogenation of allylic sulfones catalyzed by Rh-(R,R)-f-spiroPhos for synthesis of chiral β-ester sulfones has been developed for the first time achieving high yields and excellent enantioselectivities (92–99.9% ee).

Study on the Effects of Additives on the Performance of Ni–Co–P Alloy Coatings Using Box–Behnken Design

Study on the Effects of Additives on the Performance of Ni–Co–P Alloy Coatings Using Box–Behnken Design

Hydroxyl-Directed Regio- and Diastereoselective Allylic Sulfone Reductions with [Sm(H2O)n]I2.

Allylic 1,2- and 1,3-hydroxy phenyl sulfones undergo regioselective and diastereoselective desulfonylation with double bond migration upon treatment with [Sm(H2O)n]I2. Selectivity in these reactions is thought to arise from the formation of a chelated organosamarium intermediate followed by intramolecular protonation by samarium-bound water, which is supported by observed diastereoselectivity and stereospecificity trends along with deuterium labeling experiments. The reaction was then featured in the synthesis of the phenolic fragment of the thailandamide natural products.