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A large number of fluorination methods have been developed, but the construction of a tertiary C-F bond remains challenging. Herein, we describe an efficient dehydroxylative fluorination of tertiary alcohols with Selectfluor via the activation of a hydroxyl group by a Ph2PCH2CH2PPh2/ICH2CH2I system. Although the reagents appear to be not compatible (Selectfluor with the phosphine and I- generated in situ), the reactions occur rapidly to give the desired products in moderate to high yields. This work may present a new discovery in fluorination of alcohols since the reported methods are mainly limited to primary and secondary alcohols.

A large number of efficient cyanation methods have been developed because of the wide range of applications of nitriles, but conventional methods usually suffer from the need for a toxic cyanation reagent. Although difluorocarbene chemistry has received increasing attention, the use of difluorocarbene as a sources of the nitrile carbon for nitrile groups remains largely unexplored. We describe a difluorocarbene-based cyanation of aryl iodides promoted by a cheap copper source, Cu(NO3)2·2.5H2O, under an air atmosphere. Ph3P+CF2CO2 –, an easily available and shelf-stable difluorocarbene reagent, and NaNH2 are used as the carbon source and the nitrogen source for the nitrile group, respectively. The cyanation protocol is attractive because no toxic reagent is used and performing the reactions under an air atmosphere is operationally convenient.

Described here is the radical-mediated hydrodifluoromethylation of alkenes that occurs under transition-metal-free conditions by using the phosphonium salt [Ph3P+CF2H]Br− under the irradiation of 26 W household compact fluorescent light. The reaction lends itself to a convenient protocol for the installation of a C–CF2H bond while maintaining good functional group tolerance.

Ph3P/I–-promoted dichlorination and dibromination of epoxides by using XCH2CH2X (X = Cl or Br) as the halogen source and reaction solvent is described. All reagents are widely available and easy to handle, and mild conditions and operational simplicity make this protocol attractive.

Although CF3SO2Cl is an efficient chlorotrifluoromethylation reagent, an expensive transition metal complex usually has to be used. We found that CuCl2-catalyzed chlorotrifluoromethylation of alkenes with CF3SO2Cl occurred smoothly under mild conditions. A wide substrate scope and good functional group compatibility were observed.

Owing to the special effects of the fluorine element, including high electronegativity and small atomic radius, the incorporation of a fluorinated group into organic molecules may modify their physical, chemical, and biological properties. Fluorine-containing compounds have found widespread application in a variety of areas, and thus, the development of efficient reagents and methods for the incorporation of fluorinated groups has become a subject of significant interest.Described in this Account are our recent discoveries in the chemistry of fluorinated ylides/carbenes and related intermediates generated from phosphonium/sulfonium salts. Initially, we obtained the (triphenylphosphonio) difluoroacetate, Ph

To provide feasible methods for the extraction of valuable metals from spent batteries or low-grade primary ores, the extraction behavior of some representative acidic phosphorus-containing compounds (APCCs) as extractants is evaluated from the perspective of experimental and theoretical investigations in this work. Aqueous solutions containing five metal ions, Ca(II), Co(II), Mg(II), Mn(II), and Ni(II), were made to simulate leaching liquids, and the extraction of these metals was investigated. A simplified calculated model was used to evaluate the interaction between each extractant and metal ions. The calculation results agree well with the experimental tests in trend. This work not only provides potential extractants for the extraction of valuable metals from spent batteries or low-grade primary ores but also demonstrates the practicability of the simplified calculation model.

Ag-mediated trifluoromethylthiolation of inert Csp3–H bond with CF3SOCl is described. Widely available reagents and operational simplicity make this protocol attractive.

As a versatile intermediate, difluorocarbene is an electron-deficient transient species, meaning that its oxidation would be challenging. Herein we show that the oxidation of difluorocarbene could occur smoothly to generate carbonyl fluoride. The oxidation process is confirmed by successful trifluoromethoxylation, 18O-trifluoromethoxylation, the observation of AgOCF3 species, and DFT calculations., Difluorocarbene is a versatile and efficient intermediate for fluorine incorporation. Here, the authors show that difluorocarbene can be oxidized to carbonyl fluoride and this process is confirmed in 18O-trifluoromethoxylation reactions, by observation of AgOCF3 species and theory.

Summary: The CF3O functional group is a unique fluorinated group that has received a great deal of attention in medicinal chemistry and agrochemistry. However, trifluoromethoxylation of substrates remains a challenging task. Herein we describe the dehydroxytrifluoromethoxylation of alcohols promoted by a R3P/ICH2CH2I (R3P = Ph3P or Ph2PCH=CH2) system in DMF. P-I halogen bonding drives the reaction of R3P with ICH2CH2I in DMF to generate iodophosphonium salt (R3P+I I−) and a Vilsmeier-Haack-type intermediate, both of which could effectively activate alcohols, thus enabling a fast (15 min) trifluoromethoxylation reaction. A wide substrate scope and a high level of functional group tolerance were observed. : Chemistry; Organic Chemistry; Organic Synthesis Subject Areas: Chemistry, Organic Chemistry, Organic Synthesis

An efficient reagent system, Ph3P/XCH2CH2X (X = Cl, Br, or I), was very effective for the deoxygenative halogenation (including fluorination) of alcohols (including tertiary alcohols) and aldehydes. The easily available 1,2-dihaloethanes were used as key reagents and halogen sources. The use of (EtO)3P instead of Ph3P could also realize deoxy-halogenation, allowing for a convenient purification process, as the byproduct (EtO)3P═O could be removed by aqueous washing. The mild reaction conditions, wide substrate scope, and wide availability of 1,2-dihaloethanes make this protocol attractive for the synthesis of halogenated compounds.

The tri- and di-fluoroethylation of alkenes with sulfonium salts, (Ph2S+CH2RF TfO−) (RF = CF3 or HCF2), by visible light photoredox catalysis to give tri-/di-fluoroethyl alkenes or methoxytri-/di-fluoroethylation products are described. It was found that varying the reaction solvent led to changes in the reaction path.

As trifluoromethylthiolation has received increasing attention recently, many CF3S-reagents and trifluoromethylthiolation methods have been developed. Herein we describe trifluoromethylthiolation of alkyl halides by using Ph3P+CF2CO2− as a fluoride and difluorocarbene source. Difluorocarbene is a versatile intermediate, but its side reactions are usually ignored and the by-products would therefore be discarded. In this work, a side reaction of difluorocarbene, the generation of a fluoride anion from difluorocarbene, was developed into a synthetic tool. Although the trifluoromethylthiolation reaction involved multi-sequential steps, the cleavage of C–F bond, the formation of CF2=S bond, F-C(S)F2 bond, and C-SCF3 bond, the conversion proceeded fast and was completed within 10 min.

The reaction of thiocarbonyl fluoride, generated from difluorocarbene, with various amines under mild conditions is described. Secondary amines, primary amines, and o-phenylenediamines are converted to thiocarbamoyl fluorides, isothiocyanates, and difluoromethylthiolated heterocycles, respectively. Thiocarbamoyl fluorides were further transformed into trifluoromethylated amines by using a one-pot process. Thiocarbonyl fluoride is generated in situ and is rapidly fully converted in one pot under mild conditions; therefore, no special safety precautions are needed.

The highly diastereoselective synthesis of CF3-containing vicinal diamines by a convenient two-step procedure without the need to isolate the intermediate products is described.

Trifluoromethylthiolation by sulfuration of difluorocarbene with elemental sulfur is described for the first time, which overrides long-standing trifluoromethyl anion-based theory. Mechanistic elucidation reveals an unprecedented chemical process for the formation of thiocarbonyl fluoride and also enables transition-metal-mediated trifluoromethylthiolation and [18 F]trifluoromethylthiolation of α-bromo carbonyl compounds with broad substrate scope and compatibility.

A fluorinated substituent on the positive phosphorus in phosphonium salt [Ph3P+CF(Me)CO2Et Br−] was found to be able to act as a nucleophile to realize monofluoroalkylation of aldehydes, ketones and imines.

The Fe-catalyzed insertion of fluoromethylcarbenes including trifluoromethylcarbene and difluoromethylcarbene generated in situ from sulfonium salts (Ph2S+CH2CF3−OTf and Ph2S+CH2CF2H −OTf) into X–H (X = Si, C and P) bonds is described. The insertion of both carbenes into the Si–H bond occurred smoothly, and trifluoromethylcarbene could also insert into C–H and P–H bonds.

The base-free O- difluoromethylation of 1,3-diones with difluorocarbene generated from difluoromethylene phosphobetaine (Ph 3 P + CF 2 CO 2 − ) is described. The convenient reactions proceeded smoothly to give difluoromethyl enol ethers in moderate to good yields.

The high demand for the biologically active CF2H-molecules has stimulated significant efforts to develop efficient methods for the installation of CF2H functionality. We found that phenylsulfonyl difluoroacetate salt (PhSO2CF2CO2− K+) could directly undergo decarboxylation under warming conditions to produce active anion (PhSO2CF2−) without the need of any base or additive, thus allowing for the subsequent nucleophilic (phenylsulfonyl)difluoromethylation of aldehydes or imines to give PhSO2CF2-alcohols or -amines, respectively. Interestingly, the removal of PhSO2 group was achieved simply by elevating the reaction temperature for the conversion of aldehydes to afford CF2H-ketones.

Affinity, which is the essential attribute of metal ions, is very important to their physical and chemical properties. To make quantitative description and deep understanding on the affinity, fourteen metal ions were considered, and two representative ligands (H2O and NH3) were selected. Five types of energy of five models have been calculated using the density functional theory. Then, the results have been applied to quantify the affinity and describe its evolution in the ligand exchange process. Three aspects, energy decomposition analysis, natural bond orbital analysis, and information-theoretic approach in density functional reactivity theory, have been considered to understand the affinity.

The installation of a HCF2 group is a research area that has received increasing attention, and deoxydifluorination of aldehydes have served as an attractive protocol due to the wide availability of aldehydes. Herein we describe a Ph2S/Selectfluor-promoted deoxydifluorination of aldehydes under mild conditions. Compared with previous deoxydifluorination methods, which usually use hazardous reagents such as SF4, DAST and Deoxo-Fluor, this protocol is quite attractive because of the safe and convenient operations, and the use of easily available reagents.

The development of efficient protocols for the synthesis of gem-difluoroolefins has received increasing attention. Given the ubiquity of hydroxyl group in biologically active molecules and synthetic intermediates, we developed a one-step protocol for the conversions of alcohols into gem-difluoroolefins. The reactions of alcohols with Ph3P+CF2CO2−/Burgess reagent in DMSO occurred smoothly to afford the final products in moderate to high yields. DMSO is not only necessary for the oxidation process, but also important for the stabilization of phosphonium ylide by trapping difluorocarbene.

Phosphonium salt ([Ph3P(+)CF2H] Br(-), DFPB) was found to be an efficient nucleophilic difluoromethylation reagent. Although DFPB is known as a phosphonium ylide precursor, its reaction with carbonyl compounds under traditional "Wittig reaction conditions" did not give the expected Wittig difluoroolefinated products, but afforded the nucleophilic difluoromethylation products, α-CF2H alcohols. Mechanistic investigation reveals that the unexpected transformation proceeded via the direct transfer of the CF2H group, which resulted from the high P-O affinity.

Medium Resolution Imaging Spectrometer MERIS, Moderate Resolution Imaging Spectroradiometer MODIS, and Sea-viewing Wide Field-of-view Sensor SeaWiFS particulate organic carbon POC concentration products for the South China Sea SCS were compared with in situ data collected from October 2007 to December 2013. Spectral remote-sensing reflectance Rrs,λ was also measured to help understand POC algorithm performance. A strict comparison of the satellite-derived POC and in situ measurements showed that MERIS, MODIS, and SeaWiFS underestimated in situ values by 29.1, 11.7, and 31.5%, respectively. Similar results were obtained with a relaxed matching criterion. Through analysis of the causes of product uncertainty, the results suggested that satellite retrieval of Rrs,λ and the global POC algorithm both have an impact on inversion accuracy. However, the formulation of the POC algorithm seems to be more critical. When a regional algorithm was developed to obtain satellite-derived POC, both the strict and relaxed comparison results showed significant improvement, but for coastal waters, both algorithms had larger errors. Other factors affecting the comparison are also discussed.

The O-difluoromethylation of 1,3-diones with S-difluoromethyl sulfonium salt is described. The sulfonium salt was previously believed to be a direct difluoromethylation reagent, but our mechanistic investigation reveals that the O-difluoromethylation reaction proceeds not only via the direct transfer of the CF2H group, but also via a difluorocarbene process. This work represents the first protocol for mild O-difluoromethylation of acyclic 1,3-diones.

The hydroperfluoroalkylation of electron-deficient olefins with perfluoroalkyl iodides promoted by a zinc/viologen system is described. Interestingly, no iodoperfluoroalkylation product was observed without the presence of a radical H-donor.

A large number of trifluoromethylthiolation methods have been developed, but a trifluoromethylthiolation reagent usually has to be used in these methods. Herein we describe a difluorocarbene-based trifluoromethylthiolation of terminal alkynes to construct a Csp SCF3 bond catalysed by a copper complex. Ph3P+CF2CO2−/S8/F− was used as a reagent system to form the CF3S− anion, and the sequential formation of CF2 S, F CF2S and C SCF3 bonds was achieved in a one-step process.

The Ph3P/ICH2CH2I system-promoted dehydroxylative substitution of alcohols was achieved to construct C–O, C–N, C–S and C–X (X = Cl, Br, and I) bonds. Compared with the previous approaches such as the Appel reaction and Mitsunobu reaction, this protocol offers some practical advantages such as safe operation and a convenient amination process.

DBU-promoted trifluoromethylation of aryl iodides with difluoromethyltriphenylphosphonium bromide (DFPB) in the presence of copper source is described. In this transformation, DBU not only acts as base to deprotonate the difluoromethyl group in DFPB to generate difluoromethylene phosphonium ylide Ph3P+CF2−, but also converts the difluorocarbene generated from ylide Ph3P+CF2− into trifluoromethyl anion, finally resulting in the trifluoromethylation of aryl iodides. The reactions proceeded smoothly to afford expected products in moderate to good yields.

Dehydroxytrifluoromethylthiolation of alcohols with a Ph3P+CF2CO2–/S8/F– system is described. Difluorocarbene generated from Ph3P+CF2CO2– would readily combine with elemental sulfur to furnish S═CF2. S═CF2 can be considered as a bifunctional intermediate, activating alcohol and providing scaffold for CF3S– formation, thus allowing for the convenient dehydroxytrifluoromethylthiolation of alcohols.

Difluoroethylsulfonium salt, Ph2S+CH2CF2H OTf−, was developed into a convenient difluoromethylcarbene reagent for the iron-catalyzed cyclopropanation of terminal olefins, giving various difluoromethyl–cyclopropanes with excellent diastereoselectivities and in high yields.

The fluorinated phosphonium salt (Ph3P+CF2CH3 BF4–) was shown to act as a nucleophilic 1,1-difluoroethylation agent to enable difluoroethylation of aldehydes and imines.

The study of transition-metal difluorocarbene complex has long been a subject of active investigation, but the transition-metal-catalyzed transfer of difluorocarbene remains a significant challenge. The Pd-catalyzed transfer of difluorocarbene is described to realize the coupling reaction of boronic acids with difluorocarbene to give (difluoromethyl)arenes and -olefins. Mechanistic investigations reveal that the Pd═CF2 complex is an important intermediate for this transformation. This complex is prone to trimerization without the presence of starting materials.

The trifluoromethylcarbene (:CHCF3) was found to be conveniently generated from (2,2,2-trifluoroethyl)diphenyl-sulfonium triflate (Ph2S(+)CH2CF3 (-)OTf), which was successfully applied in Fe-catalyzed cyclopropanation of olefins, giving the corresponding trifluoromethylated cyclopropanes in high yields.

Organic phosphonium salts have served as important intermediates in synthetic chemistry. But the use of a substituent on the positive phosphorus as a nucleophile to construct C–C bond remains a significant challenge. Here we report an efficient transition-metal-free protocol for the direct nucleophilic arylation of carbonyls and imines with tetraarylphosphonium salts in the presence of caesium carbonate. The aryl nucleophile generated from phosphonium salt shows low basicity and good nucleophilicity, as evidenced by the successful conversion of enolizable aldehydes and ketones. The reaction is not particularly sensitive to water, shows wide substrate scope, and is compatible with a variety of functional groups including cyano and ester groups. Compared with the arylmetallic reagents that are usually moisture sensitive, the phosphonium salts are shelf-stable and can be easily handled., Carbon based nucleophiles often are synthetically limited by the high basicity/reactivity of the starting materials. Here, the authors show that tetraarylphosphonium salts can be induced to act as C-aryl nucleophiles for the addition to carbonyls and imines.