Recent Advances in the Synthesis of SCF2 H- and SCF2 FG-Containing Molecules

Synthesis of deuteriodifluoromethylthiolated isocoumarins-1-imines and isocoumarins enabled by multi-component reagents system (MCRS)

The combining use of BnSCF2D, mCPBA and Tf2O serves as an efficient multi-component reagents system (MCRS) for the synthesis of deuteriodifluoromethylthiolated isocoumarins-1-imines/isocoumarins via intramolecular cyclization/deuteriodifluoromethylthiolation of 2-alkynylbenzamides/2-alkynylbenzoates. The approach features the generation of the crucial reactive electrophilic sulfonium salt through a sequence process involving the oxidation of BnSCF2D by mCPBA followed by Tf2O promoted activation.

Visible light-promoted difluoromethylthiolation of cycloalkanols by C-C bond cleavage

A mild and general methodology for the difluoromethylthiolation of cycloalkanols has been developed by employing N-difluoromethylthiophthalimide as the SCF2H radical source, in combination with an acridinium-derived organo-photosensitizer, under redox-neutral conditions. This reaction protocol demonstrates high efficiency, scalability, and mild reaction conditions, thus presenting a green approach for the rapid synthesis of distal difluoromethylthiolated alkyl ketones that are challenging to be synthesized through alternative means.

Copper-Catalyzed C-H (Phenylsulfonyl)difluoromethylation of Acrylamides: Scope, Mechanism, and Critical Role of Additives

Herein, we report the Cu-complex catalyzed, native functional group-assisted, and TFA/NMF additives promoted (phenylsulfonyl)difluoromethylation of vinylic C(sp2 )-H bond of acrylamides. Using our in-home designed reagent, this reaction enables the construction of the C(sp2 )-CF2 SO2 Ph bond from simple C-H bond activation by copper catalysis under mild reaction conditions with total Z-selectivity. The versatility of utilized fluorinated group was illustrated by its conversion into value-added CF2 moieties as well as the remarkable =CHF residue. The performed experimental and computational mechanistic studies enabled to identify the true nature of active catalyst and substrate, as well as establish critical roles of TFA and NMF additives. In this reaction, the TFA acts as a promoter of the much-needed CuII /CuII →CuIII /CuI disproportionation, while the NMF facilitates the following ligand exchange and C-C coupling processes. We ruled out the generation of radical intermediates and established the C-H activation to be irreversible and the rate-determining step of the entire process.

Carbon-Carbon Bond Cleavage for Late-Stage Functionalization

Late-stage functionalization (LSF) introduces functional group or structural modification at the final stage of the synthesis of natural products, drugs, and complex compounds. It is anticipated that late-stage functionalization would improve drug discovery's effectiveness and efficiency and hasten the creation of various chemical libraries. Consequently, late-stage functionalization of natural products is a productive technique to produce natural product derivatives, which significantly impacts chemical biology and drug development. Carbon-carbon bonds make up the fundamental framework of organic molecules. Compared with the carbon-carbon bond construction, the carbon-carbon bond activation can directly enable molecular editing (deletion, insertion, or modification of atoms or groups of atoms) and provide a more efficient and accurate synthetic strategy. However, the efficient and selective activation of unstrained carbon-carbon bonds is still one of the most challenging projects in organic synthesis. This review encompasses the strategies employed in recent years for carbon-carbon bond cleavage by explicitly focusing on their applicability in late-stage functionalization. This review expands the current discourse on carbon-carbon bond cleavage in late-stage functionalization reactions by providing a comprehensive overview of the selective cleavage of various types of carbon-carbon bonds. This includes C-C(sp), C-C(sp2), and C-C(sp3) single bonds; carbon-carbon double bonds; and carbon-carbon triple bonds, with a focus on catalysis by transition metals or organocatalysts. Additionally, specific topics, such as ring-opening processes involving carbon-carbon bond cleavage in three-, four-, five-, and six-membered rings, are discussed, and exemplar applications of these techniques are showcased in the context of complex bioactive molecules or drug discovery. This review aims to shed light on recent advancements in the field and propose potential avenues for future research in the realm of late-stage carbon-carbon bond functionalization.

[(SIPr)Ag(CF2 H)]: A Shelf-Stable, Versatile Difluoromethylation Reagent

Due to its unique physical and electrophilic properties, the difluoromethyl group (-CF2 H) has been playing an irreplaceable role in the field of pharmaceutical and agrochemical industry. Methods that could efficiently incorporate the difluoromethyl group into the target molecules are increasing in the recent years. Developing a stable and efficient difluoromethylating reagent is thus highly attractive. In this review, we describe the development of a nucleophilic difluoromethylation reagent [(SIPr)Ag(CF2 H)], including its elemental reaction, difluoromethylation reaction with different types of electrophiles, and its application in the synthesis of a nucleophilic and an electrophilic difluoromethylthiolating reagent.

Intramolecular Heterocyclization/Fluoromethylthiolation of Alkynes Enabled by a Multicomponent Reagent System

The BnSR_f (R_f = CF₂H or CF₃)/mCPBA/Tf₂O system was found to be an effective multicomponent reagent system for the one-pot synthesis of di/trifluoromethylthiolated heterocycles from alkynes. The reaction was postulated to proceed via a cascade sequence involving the oxidation of BnSR_f by mCPBA, activation of the in situ-generated sulfoxide by Tf₂O, and intramolecular cyclization/fluoromethylthiolation of the alkyne substrates enabled by the formed electrophilic sulfonium salt to give di/trifluoromethylthiolated heterocycles.

Deoxygenation of ClSO2CF2COOMe with Triphenylphosphine for the Metal-Free Direct Electrophilic Difluoroalkylthiolation of Various Heterocycles

A direct electrophilic difluoroalkylthiolation reaction of indole derivatives and other electron-rich heterocycles using methyl 2,2-difluoro-2-(chlorsulfonyl)acetate (ClSO₂CF₂COOMe) derived from Chen's reagent (FSO₂CF₂COOMe) is described. The ester group in the product can be further utilized in subsequent versatile transformations. The reactions provide good yields of the corresponding difluoroalkylthiolation products and exhibit high functional group compatibility. It is expected to serve as an alternative and practical protocol for difluoroalkylthiolation of various heterocycles.

Transition-metal-catalyzed C-H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

The last decade has witnessed the emergence of innovative synthetic tools for the synthesis of fluorinated molecules. Among these approaches, the transition-metal-catalyzed functionalization of various scaffolds with a panel of fluorinated groups (XR_F, X = S, Se, O) offered straightforward access to high value-added compounds. This review will highlight the main advances made in the field with the transition-metal-catalyzed functionalization of C(sp²) and C(sp³) centers with SCF₃, SeCF₃, or OCH₂CF₃ groups among others, by C-H bond activation. The scope and limitations of these transformations are discussed in this review.

Mechanism-Driven Development of Group 10 Metal-Catalyzed Decarbonylative Coupling Reactions

Transition-metal-catalyzed cross-coupling reactions are widely used in both academia and industry for the construction of carbon-carbon and carbon-heteroatom bonds. The vast majority of cross-coupling reactions utilize aryl (pseudo)halides as the electrophilic coupling partner. Carboxylic acid derivatives (RC(O)X) represent a complementary class of electrophiles that can engage in decarbonylative couplings to produce analogous products. This decarbonylative approach offers the advantage that RC(O)X are abundant and inexpensive. In addition, decarbonylative coupling enables both intramolecular (between R and X of the carboxylic acid derivative) as well as intermolecular bond-forming reactions (in which an exogeneous nucleophile is coupled with the R group derived from RC(O)X). In these intermolecular reactions, the X-substituent on the carboxylic acid can be tuned to facilitate both oxidative addition and transmetalation, thus eliminating the need for an exogeneous base. This Account details our group's development of a diverse variety of base-free decarbonylative coupling reactions catalyzed by group 10 metals. Furthermore, it highlights how catalyst design can be guided by stoichiometric organometallic studies of these systems.Our early studies focused on intramolecular decarbonylative couplings that transform RC(O)X to the corresponding R-X with extrusion of CO. We first identified Pd and Ni monodentate phosphine catalysts that convert aryl thioesters (ArC(O)SR) to the corresponding thioethers (ArSR). We next expanded this reactivity to fluoroalkyl thioesters, using readily available fluoroalkyl carboxylic acids as the fluoroalkyl (RF) source. A Ni-phosphinoferrocene catalyst proved optimal, and the large bite angle bidentate ligand was necessary to promote the challenging RF-S bond-forming reductive elimination step.We next pursued intramolecular decarbonylative couplings of aroyl halides. Palladium-based catalysts bearing dialkylbiaryl ligands (e.g., BrettPhos) were identified as optimal for converting aroyl chlorides (ArC(O)Cl) to aryl chlorides (ArCl). These ligands were selected based on their ability to facilitate the key C-Cl bond-forming reductive elimination step of the catalytic cycle. In contrast, all attempts to convert aroyl fluorides [ArC(O)F)] to aryl fluorides (ArF) were unsuccessful with either Pd- or Ni-based catalysts. Organometallic studies of the Ni-system show that C(O)-F oxidative addition and CO deinsertion proceed smoothly, but the resulting nickel(II) aryl fluoride intermediate fails to undergo C-F bond-forming reductive elimination.In contrast to its inertness to reductive elimination, this nickel(II) aryl fluoride proved highly reactive toward transmetalation. The fluoride ligand serves as an internal base, such that no additional base is required. We leveraged this "transmetalation active" intermediate to achieve base-free Ni-catalyzed intermolecular decarbonylative coupling reactions between aroyl fluorides and boron reagents to access both biaryl and aryl-boronate ester products. By tuning the electrophile, transmetalating reagent, and catalyst, this same approach also proved applicable to base-free intermolecular decarbonylative fluoroalkylation (between difluoromethylacetyl fluoride and arylboronate esters) and aryl amination (between phenol esters and silyl amines).Moving forward, a key goal is to identify catalyst systems that enable more challenging bond constructions via this manifold. In addition, CO inhibition remains a major issue leading to the requirement for high temperatures and high catalyst loadings. Identifying catalysts that are resistant to CO binding and/or approaches to remove CO under mild conditions will be critical for making these reactions more practical and scalable.

Directed Palladium Catalyzed C-H (Ethoxycarbonyl)difluoromethylthiolation Reactions

The unprecedented Pd-catalyzed (ethoxycarbonyl)difluoromethylthiolation reaction of various unsaturated derivatives was studied. In the presence of the (ethoxycarbonyl)difluoromethylsulfenamide reagent I and under mild reaction conditions (60 °C), both 2-(hetero)aryl and 2-(α-aryl-vinyl)pyridine derivatives were smoothly functionalized with this methodology (37 examples, up to 87 % yield). Moreover, the synthetic interest of this fluorinated moiety was further showcased by its conversion into various original fluorinated residues. Finally, a plausible mechanism for this transformation was suggested.

C3-Selective Trifluoromethylthiolation and Difluoromethylthiolation of Pyridines and Pyridine Drugs via Dihydropyridine Intermediates

Herein, we report a method for unprecedented C3-selective C-H tri- and difluoromethylthiolation of pyridines. The method relies on borane-catalyzed pyridine hydroboration for generation of nucleophilic dihydropyridines; these intermediates react with trifluoromethylthio and difluoromethylthio electrophiles to form functionalized dihydropyridines, which then undergo oxidative aromatization. The method can be used for late-stage functionalization of pyridine drugs for the generation of new drug candidates.

Difluoromethylarylation of Alkynes from [Bis(difluoroacetoxy)iodo]benzene: Access to CF2H-Containing Dibenzazepines

A photoinduced radical difluoromethylarylation via tandem addition-cyclization of alkynes with easily available [bis(difluoroacetoxy)iodo]benzene is accomplished, providing a straightforward and practical route for the construction of difluoromethylated dibenzazepines. Various sensitive functional groups can be compatible under photoinduced conditions. Mechanism investigation reveals that this transformation is initiated by the addition of alkyne with difluoromethyl radical, generated in situ from [bis(difluoroacetoxy)iodo]benzene.

Palladium-Catalyzed Regio- and Diastereoselective Olefinic C-H Difluoromethylthiolation at Room Temperature

Herein, we developed palladium-catalyzed regio- and diastereoselective difluoromethylthiolation of acrylamides to form the Z-isomer product at room temperature. Using 8-aminoquinoline as a directing group, this protocol resulted in a high efficiency under mild reaction conditions and showed good functional group tolerances, which opens a novel synthetic methodology for accessing SCF₂H-containing skeletons. Moreover, mechanistic studies were conducted to obtain insights into the reaction mechanism, and post-functionalization of the product reactions was performed.

Access to α,α-difluoro(arylthio)methyl oxetanes from α,α-difluoro(arylthio)methyl ketones and trimethylsulfoxonium halides: scope, mechanism and applications

A general and practical method for the synthesis of α,α-difluoro(arylthio)methyl oxetanes is reported that occurs by the reaction of α,α-difluoro(arylthio)methyl ketones with trimethylsulfoxonium halides. This reaction undergoes the sequential Corey-Chaykovsky...

Chemoselective Synthesis of Sulfenylated Spiroindolenines from Indolyl-ynones via Organosulfenyl Chloride-Mediated Dearomatizing Spirocyclization

A metal-free sulfenylation/spirocyclization of indolyl-ynones realized by organosulfenyl chloride, generated in situ from the reaction of disulfides and PhICl₂, is presented. This cascade one-pot process enables a chemoselective synthesis of diverse sulfenylated spiroindolenines depending on the substituent pattern at the two-position of indolyl-ynones.

Benzyl thioether formation merging copper catalysis

A novel copper-catalyzed thioetherification reaction has been developed to afford benzyl thioethers in moderate to excellent yields. Under the mild and easy-to-operate conditions, a variety of thioethers are efficiently prepared from readily available benzyl alcohols (primary, secondary, and tertiary) and thiols in the presence of Cu(OTf)2 as the Lewis acid catalysis. This C-S bond formation protocol furnishes exceptional chemoselectivity, and the preliminary mechanism studies show that the reaction should proceed through a Lewis-acid-mediated SN1-type nucleophilic attack of the carbocations formed in situ.

Catalytic regioselective construction of phenylthio- and phenoxyldifluoroalkyl tetrazoles from difluorodiazoketones

Here we report the design and synthesis of two new difluoro-diazoketone reagents (difluorophenylthiol diazoketone and difluorophenoxyl diazoketone) and their [3+2] cycloaddition reactions with aryldiazonium salts under silver catalysis conditions. This protocol enables regioselective access to a broad scope of difluorophenylthiol- and difluorophenoxyl-substituted tetrazole-carbinols in a one-pot operation. Further synthetic derivatizations including dephenylthiolation and unexpected phenylthiol group migration/fluorination allow the efficient preparation of α-difluoromethyl tetrazole-carbinols and α-trifluoromethyl tetrazole-thioethers.

C-H Electrophilic (phenylsulfonyl)difluoromethylation of (hetero)arenes with a newly designed reagent

The synthesis of an original electrophilic difluoromethylating reagent was successfully achieved upon a straightforward protocol (3 steps). Like a Swiss army knife, this bench-stable reagent allowed the functionalization of various classes of compounds under mild and transition metal-free conditions. Hence, an efficient and operationally simple tool for the construction of C(sp2)-, C(sp3)- and S-CF2SO2Ph bonds was provided, expanding the chemical space of PhSO2CF2-containing molecules. Late-stage functionalization of bioactive molecules and the synthesis of PhSO2CF2- and HCF2-analogs of Lidocaine were also successfully achieved.

Catalyst-free gem-chlorosulfurization of difluoromethyl-substituted diazo compounds with disulfide and PhICl2

A series of gem-chlorosulfurization products bearing difluoromethyl substituents were synthesized in high to excellent yields directly from p-toluenesulfonyl difluorodiazoethane (TsCF₂CHN₂), disulfides and PhICl₂ without any catalysts or additives. The mild reaction conditions and high functional group compatibility indicated the utility and sustainability of the method. In addition, the gem-chlorosulfurization products could be efficiently converted to sulfur-containing and aryl substituted difluoromethyl derivatives by a feasible multi-component operation.

Synthesis of (benzenesulfonyl)difluoromethyl thioethers from ((difluoromethyl)sulfonyl)benzene and organothiocyanates generated in situ

Easily available aryl and alkyl thiocyanates were converted into the corresponding (benzenesulfonyl)difluoromethyl thioethers via the direct nucleophilic substitution of ((difluoromethyl)-sulfonyl)benzene under transition metal free conditions. Combined with various thiocyanation methods, this reaction can allow late-stage (benzenesulfonyl)difluoromethylthiolation of alkyl halides and aryl diazonium salts.

Difluoromethylthiolator: A Toolbox of Reagents for Difluoromethylthiolation

Recently, the strategic installation of a fluorine atom or a fluoroalkyl group site-selectively at the specific position of the target molecule has become a routine approach and daily practice for medicinal chemists in their endeavor to fine tune the structure of the lead compound to improve its physicochemical properties such as the cell membrane permeability and metabolic stability. Among many fluoroalkyl groups, the difluoromethylthio group (-SCF₂H) has attracted recent intense attention. Largely due to the weak acidity of the proton in the difluoromethylthio group, the difluoromethylthio group is generally considered to be a lipophilic hydrogen-bonding donor and a bioisostere of the hydroxy/thio group that might interact with the heteroatom of the enzyme via a hydrogen bond to improve the binding selectivity of the drug molecule. Besides, the difluoromethylthio group is less lipophilic, less electron-withdrawing, and less stable to the acidic or basic environment than its analogue trifluoromethylthio group (-SCF₃), making it easier to regulate the metabolic stability of drug molecules. These beneficial effects render the difluoromethylthio group one of the most favorable functional groups in drug design; consequently, there is an urgent need to develop new strategies for the efficient introduction of the difluoromethylthio group into small molecules under mild conditions. Over the last few decades, several different approaches to the preparation of difluoromethylthiolated compounds have been developed, including the difluoromethylation of thiolated substrates with an electrophilic/nucleophilic difluoromethylating reagent or the insertion of a difluoromethyl carbene into the S-H bond of the thiols. In contrast, we adopt an alternative approach to the preparation of difluoromethylthiolated compounds by late-stage direct difluoromethylthiolation of the specific substrates with a difluoromethylthiolating reagent. With this aim in mind, in the last 6 years we have successfully developed a toolbox of reagents that are capable of the direct introduction of the difluoromethylthio group into the target molecules, including nucleophilic difluoromethylthiolating reagent [(SIPr)AgSCF₂H] I, electrophilic difluoromethylthiolating reagent PhthSCF₂H II, three optically pure difluoromethylthiolating reagents camphorsultam-SCF₂H III, radical difluoromethylthiolating reagent PhSO₂SCF₂H IV, and reagent PhSO₂SCFClH V that could be used for the preparation of ¹⁸F-labeled [¹⁸F]ArSCF₂H. These reagents reacted with a broad range of substrates to get access to difluoromethylthiolated compounds efficiently, thus providing medicinal chemists a powerful weapon for the direct introduction of the difluoromethylthio group into promising molecules during the search for new drugs.

Iron-Catalyzed, Site-Selective Difluoromethylthiolation (-SCF2H) and Difluoromethylselenation (-SeCF2H) of Unactivated C(sp3)-H Bonds in N-Fluoroamides

The iron-catalyzed δ-C(sp³)-H bond difluoromethylthiolation and difluoromethylselenation of aliphatic amides with high site selectivity are reported. Essential to the success is the employment of an amide radical formed in situ to activate the inert C(sp³)-H bond and the utilization of the easily handled PhSO₂SCF₂H and PhSO₂SeCF₂H as coupling reagents under mild conditions. This scalable protocol exhibits a broad substrate scope bearing versatile functional groups. Mechanistic studies indicate that the reaction proceeds through -SCF₂H and -SeCF₂H radical transfer.

Radical-Promoted Distal C-H Functionalization of C(sp3 ) Centers with Fluorinated Moieties

Due to their unique properties, fluorinated scaffolds are pivotal compounds in pharmaceuticals, agrochemicals, and materials science. Over the last years, the development of versatile strategies for the selective synthesis of fluorinated molecules by direct C-H bond functionalization has attracted a lot of attention. In particular, the design of novel transformations based on a radical process was a bottleneck for distal C-H functionalization reactions, offering synthetic solutions for the selective introduction of fluorinated groups. This Minireview highlights the major contributions in this blossoming field. The development of new methodologies for the remote functionalization of aliphatic derivatives with various fluorinated groups based on a 1,5-hydrogen atom transfer process and a β-fragmentation reaction will be showcased and discussed.

Wonderful fusion of organofluorine chemistry and decarboxylation strategy

Decarboxylation strategy has been emerging as a powerful tool for the synthesis of fluorine-containing organic compounds that play important roles in various fields such as pharmaceuticals, agrochemicals, and materials science. Considerable progress in decarboxylation has been made over the past decade towards the construction of diverse valuable fluorinated fine chemicals for which the fluorinated part can be brought in two ways. The first way is described as the reaction of non-fluorinated carboxylic acids (and their derivatives) with fluorinating reagents, as well as fluorine-containing building blocks. The second way is dedicated to the exploration and the use of fluorine-containing carboxylic acids (and their derivatives) in decarboxylative transformations. This review aims to provide a comprehensive summary of the development and applications of decarboxylative radical, nucleophilic and cross-coupling strategies in organofluorine chemistry.

Synthesis of Difluoromethanesulfinate Esters by the Difluoromethanesulfinylation of Alcohols

Herein, we report the first synthesis of difluoromethanesulfinate esters via the direct difluoromethanesulfinylation of alcohols with HCF₂SO₂Na/Ph₂P(O)Cl. Primary, secondary, and tertiary alcohols were converted to the corresponding difluoromethanesulfinate esters in good to excellent yields under mild conditions. The late-stage functionalization of complexed biologically active natural products was also demonstrated. The method was extended to the trifluoromethanesulfinylation of alcohols using CF₃SO₂Na in the presence of a catalytic amount of Me₃SiCl to provide trifluoromethanesulfinate esters.

Metal-Free Direct Trifluoromethylthiolation of Aromatic Compounds Using Triptycenyl Sulfide Catalyst

Herein we report an efficient synthetic method for the electrophilic trifluoromethylthiolation of aromatic compounds. The key is to use triptycenyl sulfide (Trip-SMe) and TfOH to enhance the electrophilicity of SCF₃ fragment through the formation of sulfonium intermediates. This method enables direct installation of an SCF₃ group onto unactivated aromatics at room temperature, adopting a commercially available saccharin-based reagent. Preliminary DFT calculation was carried out to investigate the substitution effect on the catalytic activity.

Benzothiazolium salts as reagents for the deoxygenative perfluoroalkylthiolation of alcohols

A series of 2-(perfluoroalkylthio)benzothiazolium (BT-SR_F) salts have been synthesized that serve as convenient sources of hitherto underexplored perfluoroalkylthiolate anions. An investigation of their reactivity in a deoxygenative nucleophilic substitution reaction led to the development of an unprecedented process that provides pentafluoroethyl and heptafluoropropyl thioethers directly from readily available alcohols.

Photoredox-catalyzed direct C(sp2)–H difluoromethylation of enamides or heterocycles with [bis(difluoroacetoxy)iodo]benzene

A photoredox-catalyzed direct C(sp2)–H difluoromethylation of enamides and heterocycles is accomplished by using easily accessible [bis(difluoroacetoxy)iodo]benzene as the CF2H source.

Deoxygenative Tri- and Difluoromethylthiolation of Carboxylic Acids with Benzothiazolium Reagents

Deoxygenative syntheses of fluorinated thioesters directly from carboxylic acids have been developed employing benzothiazolium reagents. The process using BT-SCF₃ represents an attractive approach toward these SCF₃-containing compounds that avoids the use of metal ^-SCF₃ salts or preactivated acyl electrophiles. Moreover, the in situ activation of BT-SCF₂H allows for an unprecedented nucleophilic difluoromethylthiolation reaction. DFT calculations support a mechanistic scenario involving a four-membered transition state where acyl substitution occurs without the formation of an unstable free ^-SCF₂H anion.

Nickel-Catalyzed Decarbonylative Synthesis of Fluoroalkyl Thioethers

This report describes the development of a nickel-catalyzed decarbonylative reaction for the synthesis of fluoroalkyl thioethers (R_FSR) from the corresponding thioesters. Readily available, inexpensive, and stable fluoroalkyl carboxylic acids (R_FCO₂H) serve as the fluoroalkyl (R_F) source in this transformation. Stoichiometric organometallic studies reveal that R_F-S bond-forming reductive elimination is a challenging step in the catalytic cycle. This led to the identification of diphenylphosphinoferrocene as the optimal ligand for this transformation. Ultimately, this method was applied to the construction of diverse fluoroalkyl thioethers (R_FSR), with R = both aryl and alkyl.

Design, Synthesis, and Acaricidal Activity of Phenyl Methoxyacrylates Containing 2-Alkenylthiopyrimidine

A series of novel phenyl methoxyacrylate derivatives containing a 2-alkenylthiopyrimidine substructure were designed, synthesized, and evaluated in terms of acaricidal activity. The structures of the title compounds were identified by ¹H NMR, ¹³C NMR and high-resolution mass spectra (HRMS). Compound (E)-methyl 2-(2-((2-(3,3-dichloroallylthio)-6-(trifluoromethyl)pyrimidin-4-yloxy)methyl)phenyl)-3-methoxyacr-ylate (4j) exhibited significant acaricidal activity against Tetranychus cinnabarinus (T. cinnabarinus) in greenhouse tests possessing nearly twice the larvicidal and ovicidal activity compared to fluacrypyrim. Furthermore, the results of the field trials demonstrated that compound 4j could effectively control Panonychuscitri with long-lasting persistence and rapid action. The toxicology data in terms of LD₅₀ value confirmed that compound 4j has a relatively low acute toxicity to mammals, birds, and honeybees.

Electrophilic fluoroalkylthiolation induced diastereoselective and stereospecific 1,2-metalate migration of alkenylboronate complexes

A transition metal free process for conjunctive functionalization of alkenylboron ate-complexes with electrophilic fluoroalkylthiolating reagents is described, affording β-trifluoroalkylthiolated and difluoroalkylthiolated boronic esters in good yield and excellent diastereoselectivity. The potential applicability of the method was demonstrated by the preparation of a difluoromethylthiolated mimic 12 of a potential drug molecule PF-4191834 for the treatment of asthma.

A transition metal free process for conjunctive functionalization of alkenylboron ate-complexes with electrophilic fluoroalkylthiolating reagents affords β-tri- and difluoroalkylthiolated boronic esters in good yield and diastereoselectivity.