Regio- and Stereoselective Hydroelementation of SF5-Alkynes and Further Functionalizations.

Herein is described a fully regio- and stereoselective hydroelementation reaction of SF₅-alkynes with N, O and S-nucleophiles and further functionalization of the corresponding Z-(hetero)vinyl-SF₅ intermediates, a suitable platform to access α-SF₅ ketones and esters, β-SF₅ amines and alcohols under mild reaction conditions. Experimental and computational comparative studies between SF₅- and CF₃-alkynes have been performed to highlight and explain the difference of reactivity and selectivity observed between these two fluorinated motifs.     

Addition of fluoroperoxides to perfluorovinylsulfur pentafluoride

The addition of CF₃OOCF₃ and SF₅OOSF₅ across the double bond in CF=CFSF₅ was studied with 1:1 addition products being observed in both cases. For CF₃OOCF₃, the product was CF₃OCF₂CF(OCF₃)SF₅, whereas for SF₅OOF₅ it was SF₅CF₂CF₂OSF₅. The different reaction paths are attributed to steric reasons.The telomerization of fluoroolefins with fluoroperoxides has been reported [1,2]. Hexafluoropropene, when telomerized with bis(trifluoromethyl) peroxide, (CF₃O)₂,[1] yielded a series of oils having the composition CF₃O(C₃F₆)_nOCF₃ where n . Similarly, hexafluoropropene reacted with bis(pentafluorosulfur) peroxide, (SF₅O)₂, [2] to yield a series of oils of the composition SF₅O(C₃F₆)_nOSF₅ where n was also equal to or larger than two. Surprisingly, in neither case was the 1:1 addition product found.During our investigation of new thermally stable high density fluorooils, the thermal and photochemical reactions of perfluorovinylsulfur pentafluoride, CF₂=CFSF₅, with the fluoroperoxides (CF₃O)₂ and (SF₅O)₂ were studied. By analogy with the previous work on C₃F₆ [1,2], the main products were higher telomers, however in the case of (CF₃O)₂ and CF₂=CFSF₅ we were able to isolate also the 1:1 addition product according to:

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The necessary CF₃O· radicals were generated either thermally at 185°C or by uv-photolysis at ambient temperature. The yields of (1) were 4% in the thermal and 8% in the photolytic reaction. Compound (l) is a clear liquid and was characterized by elemental analysis, molecular weight, and infrared and mass spectroscopy.     

Improved and facile addition reactions of pentafluorosulfanyl bromide

A solution of SF₅Br in CCl₃F (0.5-1 M) was utilized to effect the addition of pentafluorosulfanyl bromide (SF₅Br) to olefins. The reaction of the SF₅Br solution in the presence of triethylborane (0.1 equiv) with an olefin over 20 min at 0 °C gave pentafluorosulfanylated compound 2(a-f) in high yield (Table 2). An efficient route for the preparation of synthetically useful SF5-containing esters is also described.     

Data on the formation and decomposition of bis(pentafluorosulfur) trioxide,bis(pentafluorosulfur) dioxide,bis(pentafluorosulfur) monoxide and of the radicals SF5O2 and SF5O. A review of earlier kinetic investigations

A method is described for the preparation of pure bis(pentafluorosulfur) trioxide. The mechanisms of formation and decomposition of SF₅O₃SF₅ and SF₅O₂SF₅ are described by reference to previous kinetic studies. The dissociation energies of these oxides and of the radicals SF₅O₂ and SF₅O are given and some reactions of SF₅·, SF₅O·, and SF₅O₂· are described.     

A new synthesis of perfluoroacyl halides and anhydrides from perfluorocarboxylate salts. A synthetic study

The nucleophilic cleavage of difluorophosphine esters of perfluorocarboxylic acids by halide ions to form acyl halides has not been previously reported. Furthermore, the reactions between halophosphoryldifluorides or the anhydrides, P₂O₅F₂ and P₂O₃F₄, and perfluorocarboxylate salts produce acyl halides or acyl anhydrides, respectively.     

Halogen displacement chemistry with silver and alkali metal salts: Preparation of SF5-esters, alcohols, aliphatic olefins, acids and an iodide

It has been found that treatment of SF₅-alkyl halides, especially SF₅(CH₂)₂Br, with silver salts such as CH₃C(O)OAg, p-CH₃C₆H₄SO₃Ag, CF₃SO₃Ag and AgNO₃ provides convenient pathways for preparing the following ester compounds: SF₅CH₂CH₂R (R = CH₃COO, TosO, CF₃SO₃, NO₃), SF₅(CH₂)₃OTos, and SF₅(CF₂)₄(CH₂)₂OAc. Important derivatives prepared from these esters include SF₅(CH₂)₂OH; SF₅(CF₂)₄(CH₂)₂OH. Several alkenes SF₅C(Br)CH₂ and SF₅CH₂(COOCH₃)CCHC(O)OCH₃ are obtained using silver salts. The use of alkali metals salts with SF₅(CH₂)₃Br is studied and yields SF₅(CH₂)₃I; also, a pathway has been developed that extends for SF₅(CH₂)₃₋ the chain by two-carbon atoms and also produces the first SF₅-containing malonic acid.     

Rhenium complex-catalyzed acylative cleavage of ethers with acyl chlorides

It was found that rhenium complex was an efficient catalyst for the acylative cleavage of C-O bond of ethers with acyl chlorides. When acyclic ethers were allowed to react with acyl chlorides in the presence of a catalytic amount of ReBr(CO)₅, acylative cleavage of C-O bond of acyclic ethers smoothly proceeded to give the corresponding esters in moderate to good yields. Similarly, cyclic ethers were acylative cleaved by acyl chlorides to give the corresponding chloro substituted esters in good yields by the use of Re₂O₇ catalyst.     

Direct synthesis of fluorinated peroxides. 9. Some reactions of perfluorotertiarybutyl hydroperoxide.

The reaction of (CF₃)₃COOH with perfluoroacyl fluorides in the pressure of NaF results in the formation of new peroxy esters of the type, (CF₃)₃COOC(O)R_f. Addition of the hydroperoxide to CF₃NCF₂ yields the unstable amine (CF₃)₃COOCF₂N(H)CF₃. These reactions of (CF₃)₃COOH are compared with analogous reactions of CF₃OOH and SF₅OOH.     

Reactions of pentafluorosulfanyliminodihalosulfanes,SF5NSX2, with nucleophiles. Preparation and characterization of pentafluorosulfanylsulfinylamine,SF5NSO.

Reactions of SF₅NSF₂ with sodium alkoxides and aryloxides have produced both the mono- and disubstituted derivatives SF₅NS(F)OR and SF₅NS(OR)₂, where RCH₃, CH₂CHCH₂, C₆H₅, p-C₆H₄NO₂, p-C₆H₄Br, p-C₆H₄CN. The reaction of SF₅NSCl₂ with AgNCO produced SF₅NS(NCO)₂. This diisocyanate can also be prepared from the reaction of SF₅NSCl₂ with KOCN in liquid SO₂. The proposed intermediate, SF₅NSO, in the hydrolysis of SF₅NSF₂ was prepared from the low temperature reaction of SF₅NSCl₂ and Ag₂O in C₆H₅NO₂. The new pentafluorosulfanyl derivatives were characterized by IR, ¹H and ¹⁹F NMR, mass spectrometry and where possible ¹³C NMR and elemental analysis.     

Solvent effects in fluorine-19 NMR spectroscopy: Nonuniform shifting of the axial and equatorial fluorine resonances of the pentafluorosulfanyl group

The chemical shifts of the fluorine resonances of SF₅NSF₂ are given in fourteen different solvents. A change in solvent polarity was found to affect the axial fluorine of the SF₅ group more substantially than the equatorial fluorines. This nonuniform shifting of the axial and equatorial fluorine resonances of the SF₅ group is best explained as a trans effect and can sometimes be used to simplify complex spectra as shown in the examples SF₅NHC(O)F and SF₅NHC(O)CF₃.     

Preparation of some new pentafluorosulfur fluoroethanes; the vibrational spectrum of 1-hydro-1-pentafluorosulfur-F-ethane and its deuterium isotopomer

The preparation of 1-hydro-pentafluorosulfur-F-ethylsilver is described. AgCH(SF₅)CF₃ reacts with HCℓ and DCℓ to form HCH(SF₅)CF₃ and DCH(SF₅)CF₃·1-Pentafluoro-sulfur-F-ethylsilver reacts with Cℓ₂ and DCℓ to form CℓCF(SF₅)CF₃ and DCF(SF₅)CF₃. AgCH(SF₅)CF₃, DCH(SF₅)CF₃, CℓCF(SF₅)CF₃ and DCF(SF₅)CF₃ have not been reported previously.The vibrational spectra of HCF(SF₅)CF₃ and its deuterated analog were investigated, and a tentative assignment was made.     

Synthesis and Characterization of 2‐Pyridylsulfur Pentafluorides

Current approaches to prepare SF₅‐substituted heterocycles during the synthesis of targeted heterocyclic compounds require the use of SF₅‐functionalized aryl or alkyne reagents or SF₅Cl as a source of the SF₅ functional group. Herein we report that excess oxidative fluorination of 2,2′‐dipyridyl disulfide with a KF/Cl₂/MeCN system leads to the formation of thirteen new 2‐pyridylsulfur chlorotetrafluorides (2‐SF₄Cl‐pyridines). These molecules are found to undergo further chlorine–fluorine exchange reactions by treatment with silver(I) fluoride enabling ready access to a series of ten new substituted 2‐pyridylsulfur pentafluorides (2‐SF₅‐pyridines). This is the first preparatively simple and readily scalable example of the transformation of an existing heterocyclic sulfur functionality to prepare SF₅‐substituted heterocycles.     

Mono- and dihydryl-pentafluorosulfur-F-alkanes [1]

The systematic preparation of partially fluorinated pentafluorosulfur alkanes containing no additional halogens is reported. Thus, the indirect addition of “HF” (via KF/formamide) to SF₅CH=CF₂, SF₅CFCF₂, and SF₅C(CF₃)CF₂ produces SF₅CH(in2)CF₃, SF₅CHFCF₃, and SF₅C(CF₃)₂H respectively. The monohydryl-pentafluorosulfur-F- alkanes react readily with S₂O₆F₂ to form the corresponding fluorosulfates by oxidative displacement of hydrogen, while the dihydryl derivative undergoes cleavage to produce F-acetyl fluoride. Efforts to convert some of the new materials to the important but unknown pentafluorosulfur “ketone,” SF₅C(O)CF₃, were unsuccessful.     

New acrylate systems: derivatives of β-SF5-acrylic acid

Addition of pentafluorothio bromide, SF₅Br, to ethyl propiolate results in an 1:1 adduct, SF₅CHCBrC(O)OC₂H₅, and a small amount of a 1:2 adduct. The former is converted by reduction to the corresponding β-SF₅-acrylic ester, SF₅CHCHC(O)OC₂H₅. Treatment of SF₅CH₂CBr(CH₃)C(O)OCH₃ with base produces methyl-β-SF₅-methacrylate, SF₅CHC(CH₃)C(O)OCH₃. The preparation and characterization of these new compounds are described.     

Spectrokinetic study of SF5 and SF5O2 radicals and the reaction of SF5O2 with NO

UV spectra of SF₅ and SF₅O₂ radicals in the gas phase at 295 K have been quantified using a pulse radiolysis UV absorption technique. The absorption spectrum of SF₅ was quantified from 220 to 240 nm. The absorption cross section at 220 nm was (5.5 ± 1.7) × 10⁻¹⁹ cm². When SF₅ was produced in the presence of O₂ an equilibrium between SF₅, O₂, and SF₅O₂ was established. The rate constant for the reaction of SF₅ radicals with O₂ was (8 ± 2) × 10⁻¹³ cm³ molecule⁻¹ s⁻¹. The decomposition rate constant for SF₅O₂ was (1.0 ± 0.5) × 10⁵ s⁻¹, giving an equilibrium constant of K_eq = [SF₅O₂]/[SF₅][O₂] = (8.0 ± 4.5) × 10⁻¹⁸ cm³ molecule⁻¹. The SF₅ O₂ bond strength is (13.7 ± 2.0) kcal mol⁻¹. The SF₅O₂ spectrum was broad with no fine structure and similar to the UV spectra of alkyl peroxy radicals. The absorption cross section at 230 nm was found to (3.7 ± 0.9) × 10⁻¹⁸ cm². The rate constant of the reaction of SF₅O₂ with NO was measured to (1.1 ± 0.3) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ by monitoring the kinetics of NO₂ formation at 400 nm. The rate constant for the reaction of F atoms with SF₄ was measured by two relative methods to be (1.3 ± 0.3) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹. © 1994 John Wiley & Sons, Inc.     

Die Kristallstruktur des SF5−-Anions

Crystal Structure of the SF₅^?-Anion The carbanion SF₅? C(CF₃)₂^? decomposes slowly forming SF₅^?, and (CF₃)₂C?C(CF₃)₂. The pentafluorosulfates(IV) grow in large crystals which are stable for prolonged times in presence of a SF₄ vapour pressure. Crystal structure analysis of Rb⁺SF₅^? (Pbnm, a = 776.1(14), b = 990.3(5), c = 614.1(3) pm, Z = 4) revealed the SF₅^? anion in the expected square pyramidal structure. The axial bond is 15.9 pm shorter than the average equatorial bonds. The sulfur atom is located below the equatorial fluorine atoms. Pure Cs⁺SF₅^?-crystals seem to be notoriously twinned. Accidentally we isolated a double salt (Cs⁺)₆(SF₅^?)₄ (HF₂^?)₂ (P4 b2, a = 1031.7(15), c = 627.6(9) pm, Z = 1). Herein the anion SF₅^? has the same structure as in Rb⁺SF₅^?.     

Synthesis of Phthalocyanines with a Pentafluorosulfanyl Substituent at Peripheral Positions

The pentafluorosulfanyl (SF₅) group is more electronegative, lipophilic and sterically bulky relative to the well‐explored trifluoromethyl (CF₃) group. As such, the SF₅ group could offer access to pharmaceuticals, agrochemicals and optoelectronic materials with novel properties. Here, the first synthesis of phthalocyanines (Pcs), a class of compounds used as dyes and with potential as photodynamic therapeutics, with a SF₅ group directly attached on their peripheral positions is disclosed. The key for this work is the preparation of a series of SF₅‐containing phthalonitriles, which was beautifully regio‐controlled by a stepwise cyanation via ortho‐lithiation/iodination from commercially available pentafluorosulfanyl arenes. The macrocyclization of the SF₅‐containing phthalonitriles to SF₅‐substituted Pcs required harsh conditions with the exception of the synthesis of β‐SF₅‐substituted Pc. The regiospecificity of the newly developed SF₅‐substituted Pcs observed by UV/Vis spectra and fluorescence quantum yields depend on the peripheral positon of the SF₅ group.     

Strukturen von SF5-substituierten Metallkomplexen

Structures of SF₅-substituted Metal Complexes Crystal and molecular structure of [(CO)₆Co₂(F₅S? C?C? SF₅)], [(CO)₄Co? CH₂? SF₅] and [(CO)₅Mn? S? CF?N? SF₅] are reported. Whereas the first two complexes are formed as expected, the latter one is the product of an unclear reaction pathway. In decomposition reactions of [(CO)₄Co? CH₂? SF₅] and [(CO)₅Mn? CH₂? SF₅] H₂C?SF₄ is produced. This allows a one step preparation of this elusive, simplest alkylidine sulfur tetrafluoride.     

ChemInform Abstract: The cis Influence of Bromine in SF5Br. A Combined Electron Diffraction-Microwave Study.

The results obtained from the electron diffraction study of the gas phase molecular structure of SF₅Br demonstrate a small cis influence of Br on the SF₅ group, i.e., the equatorial bonds (cis to Br) are affected more strongly by the substituent than the axial bond.     

Reaktionen des (Pentafluorsulfanyl)dichloramin

Reactions of Pentafluorosulfanyldichloroamine The previously unexplored reaction chemistry of pentafluorosulfanyldichloroamine has now led to the novel compounds SF₅N?PCl₃ and SF₅N?SeCl₂. Even though both compounds are produced in high yield (>80%), they were found to decompose readily at room temperature. SF₅NCl₂ has also been found to react with S₂Cl₂ or SCl₂ to give SF₅N?SCl₂, and with SF₅N?SCl₂ to give SF₅N?S?NSF₅. Finally, the adduct SF₅NH₂ · HCl is formed from SF₅NCl₂ and HCl.