Perfluorobutanesulfonyl fluoride

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Perfluorobutanesulfonyl fluoride
Nonafluorobutanesulfonyl fluoride acsformat.svg
Names
Preferred IUPAC name
1,1,2,2,3,3,4,4,4-Nonafluorobutane-1-sulfonyl fluoride
Identifiers
3D model (JSmol)
AbbreviationsNfF
ChemSpider
ECHA InfoCard 100.006.175 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 206-792-6
PubChem CID
UNII
  • InChI=1S/C4F10O2S/c5-1(6,3(9,10)11)2(7,8)4(12,13)17(14,15)16
    Key: LUYQYZLEHLTPBH-UHFFFAOYSA-N
  • InChI=1/C4F10O2S/c5-1(6,3(9,10)11)2(7,8)4(12,13)17(14,15)16
    Key: LUYQYZLEHLTPBH-UHFFFAOYAE
  • C(C(C(F)(F)S(=O)(=O)F)(F)F)(C(F)(F)F)(F)F
Properties
C4F10O2S
Molar mass 302.09 g/mol
Density 1.682 g/mL [1]
Melting point <−120 °C (−184 °F; 153 K)
Boiling point 65 to 66 °C (149 to 151 °F; 338 to 339 K) [2]
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Perfluorobutanesulfonyl fluoride (nonafluorobutanesulfonyl fluoride, NfF) is a colorless, volatile liquid that is immiscible with water but soluble in common organic solvents. It is prepared by the electrochemical fluorination of sulfolane. NfF serves as an entry point to nonafluorobutanesulfonates (nonaflates), which are valuable as electrophiles in palladium catalyzed cross coupling reactions. As a perfluoroalkylsulfonylating agent, NfF offers the advantages of lower cost and greater stability over the more frequently used triflic anhydride. The fluoride leaving group is readily substituted by nucleophiles such as amines, phenoxides, and enolates, giving sulfonamides, aryl nonaflates, and alkenyl nonaflates, respectively. However, it is not attacked by water (in which it is stable at pH<12). Hydrolysis by barium hydroxide gives Ba(ONf)2, which upon treatment with sulfuric acid gives perfluorobutanesulfonic acid and insoluble barium sulfate.

Contents

Purification

NfF purification.svg

Commercially available NfF is contaminated with 6-10 mol % perfluorosulfolane derived from its production. This is readily removed by vigorously stirring the commercial material with a concentrated aqueous solution of K3PO4 and K2HPO4 in a 1:1 molar ratio for 96 hours. This treatment, followed by removal of the aqueous layer and distillation from P2O5, gives a product that contains >99 mol % NfF with near quantitative recovery. [3]

Synthesis of aryl and alkenyl nonaflates

As mentioned above, aryl and alkenyl nonaflates are useful as electrophiles in palladium catalyzed cross coupling reactions. Their reactivity generally mirrors that of the more commonly encountered triflate electrophiles, but nonaflates tend to be less prone to hydrolysis to ketones (in the case of alkenyl sulfonates) and phenols (in the case of aryl sulfonates). Their resistance to hydrolysis makes nonaflates superior electrophiles in Buchwald-Hartwig couplings, where this side reaction can be deleterious to yields of the desired product. [4]

The sodium enolates of β-ketoesters react with 1.15 equivalents of NfF to give the corresponding alkenyl nonaflates in high yield. Ethyl 2-methylacetoacetate (R=R'=Me) gives the geometrically pure E isomer by this method. [5]

Nonaflates from beta keto esters.gif

Simple aldehydes and ketones react with NfF in the presence of bases such as DBU or phosphazenes to give alkenyl nonaflates in high yields without formation of a discrete enolate. Use of the P2 phosphazene base at -30 to -20 °C gives the less substituted alkenyl nonaflate with unsymmetrically substituted ketones. [3] Similar reactions with triflic anhydride generally require the use of the expensive 2,6-di-tert-butylpyridine to achieve high yields.

The reaction of enolates with NfF depends strongly both on the structure of the enolate and its metal counterion. The lithium enolates of methyl ketones give mixtures of products derived from electrophilic attack on the O (expected) or C (unexpected) atoms of the enolate. This effect is particularly evident with the lithium enolate of pinacolone, which gives a 2:1 mixture favoring C-attack. More substituted lithium enolates give only products of O sulfonylation in variable yields. [6]

Pinacolone lithium enolate nonaflation correction.gif

Trimethylsilyl enol ethers react with NfF in the presence of a substoichiometric fluoride source at 0 °C to ambient temperature to give alkenyl nonaflates in moderate to good yields. Dried Bu4F was the preferred fluoride source in one study, [6] but CsF has been used in difficult cases with excellent results. [7]

Bis alkenyl nonaflate formation from silyl enol ether.png

Aryl nonaflates can be prepared straightforwardly from phenols and NfF in the presence of bases such as potassium carbonate [8] and Et3N [4] in near quantitative yields. Stronger bases such as NaH and BuLi [9] can also be used, but they tend to give somewhat lower yields.

Reaction with alcohols

The reaction of NfF with alcohols highlights the lability of alkyl nonaflates – in most cases, the final product of the reaction is either an alkyl fluoride (from F attack on the intermediate alkyl nonaflate) or an olefin (from elimination of NfOH from the intermediate nonaflate).

Synthesis of bis-nonafluorobutanesulfonimide (Nf2NH)

NfF reacts with ammonium chloride in the presence of triethylamine in acetonitrile to give the triethylammonium salt of the superacidic bis-nonafluorobutanesulfonimide in 97% yield. The corresponding potassium salt is obtained by treatment of a methanolic solution of the triethylammonium salt with KOH. [10] The acid is obtained by ion exchange chromatography of the triethylammonium salt with Amberlite IR-100 as the stationary phase and methanol as the eluent. [11] The actual species produced in the latter procedure is likely MeOH2+ Nf2N.

Related Research Articles

In organic chemistry, a nucleophilic addition reaction is an addition reaction where a chemical compound with an electrophilic double or triple bond reacts with a nucleophile, such that the double or triple bond is broken. Nucleophilic additions differ from electrophilic additions in that the former reactions involve the group to which atoms are added accepting electron pairs, whereas the latter reactions involve the group donating electron pairs.

The Stille reaction is a chemical reaction widely used in organic synthesis. The reaction involves the coupling of two organic groups, one of which is carried as an organotin compound. A variety of organic electrophiles provide the other coupling partner. The Stille reaction is one of many palladium-catalyzed coupling reactions.

The Suzuki reaction is an organic reaction, classified as a cross-coupling reaction, where the coupling partners are a boronic acid and an organohalide and the catalyst is a palladium(0) complex. It was first published in 1979 by Akira Suzuki, and he shared the 2010 Nobel Prize in Chemistry with Richard F. Heck and Ei-ichi Negishi for their contribution to the discovery and development of palladium-catalyzed cross-couplings in organic synthesis. This reaction is also known as the Suzuki–Miyaura reaction or simply as the Suzuki coupling. It is widely used to synthesize polyolefins, styrenes, and substituted biphenyls. Several reviews have been published describing advancements and the development of the Suzuki reaction. The general scheme for the Suzuki reaction is shown below, where a carbon-carbon single bond is formed by coupling a halide (R1-X) with an organoboron species (R2-BY2) using a palladium catalyst and a base.

Organoboron chemistry

Organoborane or organoboron compounds are chemical compounds of boron and carbon that are organic derivatives of BH3, for example trialkyl boranes. Organoboron chemistry or organoborane chemistry is the chemistry of these compounds.

Bamford–Stevens reaction

The Bamford–Stevens reaction is a chemical reaction whereby treatment of tosylhydrazones with strong base gives alkenes. It is named for the British chemist William Randall Bamford and the Scottish chemist Thomas Stevens Stevens (1900–2000). The usage of aprotic solvents gives predominantly Z-alkenes, while protic solvent gives a mixture of E- and Z-alkenes. As an alkene-generating transformation, the Bamford–Stevens reaction has broad utility in synthetic methodology and complex molecule synthesis.

The Hiyama coupling is a palladium-catalyzed cross-coupling reaction of organosilanes with organic halides used in organic chemistry to form carbon–carbon bonds. This reaction was discovered in 1988 by Tamejiro Hiyama and Yasuo Hatanaka as a method to form carbon-carbon bonds synthetically with chemo- and regioselectivity. The Hiyama coupling has been applied to the synthesis of various natural products.

The Corey–House synthesis is an organic reaction that involves the reaction of a lithium diorganylcuprate with an organic pseudohalide to form a new alkane, as well as an ill-defined organocopper species and lithium halide as byproducts.

Schwartzs reagent Chemical compound

Schwartz's reagent is the common name for the organozirconium compound with the formula (C5H5)2ZrHCl, sometimes called zirconocene hydrochloride or zirconocene chloride hydride, and is named after Jeffrey Schwartz, a chemistry professor at Princeton University.This metallocene is used in organic synthesis for various transformations of alkenes and alkynes.

Organozinc compound

Organozinc compounds in organic chemistry contain carbon to zinc chemical bonds. Organozinc chemistry is the science of organozinc compounds describing their physical properties, synthesis and reactions.

Organocopper compound Compound with carbon to copper bonds

Organocopper compounds in organometallic chemistry contain carbon to copper chemical bonds. Organocopper chemistry is the science of organocopper compounds describing their physical properties, synthesis and reactions. They are reagents in organic chemistry.

The Buchwald–Hartwig amination is a chemical reaction used in organic chemistry for the synthesis of carbon–nitrogen bonds via the palladium-catalyzed coupling reactions of amines with aryl halides. Although Pd-catalyzed C-N couplings were reported as early as 1983, Stephen L. Buchwald and John F. Hartwig have been credited, whose publications between 1994 and the late 2000s established the scope of the transformation. The reaction's synthetic utility stems primarily from the shortcomings of typical methods for the synthesis of aromatic C–N bonds, with most methods suffering from limited substrate scope and functional group tolerance. The development of the Buchwald–Hartwig reaction allowed for the facile synthesis of aryl amines, replacing to an extent harsher methods while significantly expanding the repertoire of possible C–N bond formation.

Tripotassium phosphate Chemical compound

Tripotassium phosphate, also called tribasic potassium phosphate is a water-soluble salt with the chemical formula K3PO4.(H2O)x (x = 0, 3, 7, 9). Tripotassium phosphate is basic.

In organic synthesis, cyanation is the attachment or substitution of a cyanide group on various substrates. Such transformations are high-value because they generate C-C bond. Furthermore nitriles are versatile functional groups.

Organobismuth chemistry

Organobismuth chemistry is the chemistry of organometallic compounds containing a carbon to bismuth chemical bond. Applications are few. The main bismuth oxidation states are Bi(III) and Bi(V) as in all higher group 15 elements. The energy of a bond to carbon in this group decreases in the order P > As > Sb > Bi. The first reported use of bismuth in organic chemistry was in oxidation of alcohols by Challenger in 1934 (using Ph3Bi(OH)2). Knowledge about methylated species of bismuth in environmental and biological media is limited.

Electrophilic amination is a chemical process involving the formation of a carbon–nitrogen bond through the reaction of a nucleophilic carbanion with an electrophilic source of nitrogen.

The Baylis–Hillman reaction is a carbon-carbon bond forming reaction between the α-position of an activated alkene and a carbon electrophile such as an aldehyde. Employing a nucleophilic catalyst, such as a tertiary amine and phosphine, this reaction provides a densely functionalized product. It is named for Anthony B. Baylis and Melville E. D. Hillman, two of the chemists who developed this reaction while working at Celanese. This reaction is also known as the Morita–Baylis–Hillman reaction or MBH reaction, as K. Morita had published earlier work on it.

Metal-catalyzed C–H borylation reactions are transition metal catalyzed organic reactions that produce an organoboron compound through functionalization of aliphatic and aromatic C–H bonds and are therefore useful reactions for carbon–hydrogen bond activation. Metal-catalyzed C–H borylation reactions utilize transition metals to directly convert a C–H bond into a C–B bond. This route can be advantageous compared to traditional borylation reactions by making use of cheap and abundant hydrocarbon starting material, limiting prefunctionalized organic compounds, reducing toxic byproducts, and streamlining the synthesis of biologically important molecules. Boronic acids, and boronic esters are common boryl groups incorporated into organic molecules through borylation reactions. Boronic acids are trivalent boron-containing organic compounds that possess one alkyl substituent and two hydroxyl groups. Similarly, boronic esters possess one alkyl substituent and two ester groups. Boronic acids and esters are classified depending on the type of carbon group (R) directly bonded to boron, for example alkyl-, alkenyl-, alkynyl-, and aryl-boronic esters. The most common type of starting materials that incorporate boronic esters into organic compounds for transition metal catalyzed borylation reactions have the general formula (RO)2B-B(OR)2. For example, bis(pinacolato)diboron (B2Pin2), and bis(catecholato)diborane (B2Cat2) are common boron sources of this general formula.

The Chan–Lam coupling reaction – also known as the Chan–Evans–Lam coupling is a cross-coupling reaction between an aryl boronic acid and an alcohol or an amine to form the corresponding secondary aryl amines or aryl ethers, respectively. The Chan–Lam coupling is catalyzed by copper complexes. It can be conducted in air at room temperature. The more popular Buchwald–Hartwig coupling relies on the use of palladium.

Stannatrane

A stannatrane is a tin-based atrane belonging to the larger class of organostannanes. Though the term stannatrane is often used to refer to the more commonly employed carbastannatrane, azastannatranes have also been synthesized. Stannatrane reagents offer highly selective methods for the incorporation of "R" substituents in complex molecules for late-stage diversification. These reagents differ from their tetraalkyl organostannane analogues in that there is no participation of dummy ligands in the transmetalation step, offering selective alkyl transfer in Stille Coupling reactions. These transmetalating agents are known to be air- and moisture-stable, as well as generally less toxic than their tetraalkyl counterparts.

Mizoroki-Heck vs. Reductive Heck

The Mizoroki−Heck coupling of aryl halides and alkenes to form C(sp2)–C(sp2) bonds has become a staple transformation in organic synthesis, owing to its broad functional group compatibility and varied scope. In stark contrast, the palladium-catalyzed reductive Heck reaction has received considerably less attention, despite the fact that early reports of this reaction date back almost half a century. From the perspective of retrosynthetic logic, this transformation is highly enabling because it can forge alkyl–aryl linkages from widely available alkenes, rather than from the less accessible and/or more expensive alkyl halide or organometallic C(sp3) synthons that are needed in a classical aryl/alkyl cross-coupling.

References

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  2. "1,1,2,2,3,3,4,4,4-nonafluorobutane-1-sulphonyl fluoride". National Institute of Standards and Technology . Retrieved 22 July 2012.
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