4-(Pentafluorosulfanyl)benzenediazonium Tetrafluoroborate: A Versatile Launch Pad for the Synthesis of Aromatic SF5 Compounds via Cross Coupling, Azo Coupling, Homocoupling, Dediazoniation, and Click Chemistry

FULL PAPER

DOI: 10.1002/ejoc.201301538

4-(Pentafluorosulfanyl)benzenediazonium Tetrafluoroborate: A Versatile

Launch Pad for the Synthesis of Aromatic SF₅Compounds via Cross Coupling,

Azo Coupling, Homocoupling, Dediazoniation, and Click Chemistry

Takao Okazaki,^[a,b]Kenneth K. Laali,*^[a]Scott D. Bunge,^[c]and Sonya K. Adas^[c]

Keywords: Click chemistry / Diazo compounds / Azo coupling / Cross-coupling / Solvolysis / Fluorine / Sulfur

The reagent 4-(pentafluorosulfanyl)benzenediazonium tetra-

fluoroborate (1) was synthesized and isolated as a stable salt

for the first time; its application in a wide assortment of trans-

formations was subsequently investigated. A series of novel

SF₅-bearing alkenes, alkynes, and biaryl derivatives were

synthesized by employing Heck–Matsuda, Sonogashira, and

Suzuki coupling protocols. Dediazoniation with TMSX (X =

Hal; N₃; and CN) and NH₄SCN in [BMIM][BF₄] as solvent

furnished the corresponding p-SF₅–C₆H₄X derivatives. The

azide derivative p-SF₅–C₆H₄N₃entered into click chemistry

with phenylacetylenes to furnish the corresponding triazoles.

The 4,4Ј-bis(pentafluorosulfanyl)biphenyl was synthesized

by homo-coupling using Pd(OAc)₂. The corresponding azo

compounds were obtained through azo-coupling with reac-

tive aromatic nucleophiles (1,3-dimethoxybenzene, 1,3,5-tri-

methoxybenzene, 1,2,4-trimethoxybenzene, aniline and

phenol). Fluorodediazoniation in [BMIM][PF₆] and

[BMIM][BF₄] selectively furnished the fluoro derivative p-

SF₅–C₆H₄F. Dediazoniation in [BMIM][NTf₂] gave p-SF₅–

C₆H₄OS(O)(CF₃)=NSO₂CF₃as the major and p-SF₅–C₆H₄-

NTf₂as the minor products. Homolytic dediazoniation in

MeCN/NaI gave the unsymmetrical biaryls p-SF₅–C₆H₄-Ar

(ArH = mesitylene and p-xylene) along with p-SF₅–C₆H₄I.

Analysis of the dediazoniation product mixtures indicated

+

–

that dediazoniation of p-SF₅–C₆H₄N₂BF₄in low nucleo-

philicity, highly ionizing, solvents (TfOH, TFE, HFIP, TFAH)

is mainly heterolytic, while in MeOH it is mainly homolytic.

The isodesmic reaction p-SF₅–C₆H₄⁺+ R-C₆H₅ǞSF₅–C₆H₅+

+

p-R-C₆H₄(with R = NO₂, CF₃, H) was gauged by DFT at

various levels and by PCM.

ene and its p-nitro derivative in modest yields by reacting

the corresponding aryl disulfides or aryl sulfur trifluorides

with excess AgF₂in chlorofluorocarbon solvent at elevated

temperatures in a copper reactor.^[2]This method was later

employed by Thrasher et al.^[3]to prepare various substi-

tuted derivatives of PhSF₅in modest overall yields. Subse-

quent methods reported from other laboratories involved

elemental fluorination starting with the corresponding bis-

nitrophenyl disulfide,^[4]and high pressure reactions with

gaseous SF₅halides.^[5,6]The 3-nitro derivative is accessible

by direct electrophilic nitration of PhSF₅.^[2,4,5]A recent

method reported by Umemoto et al.^[7]involves synthesis of

ArSF₄Cl from ArSSAr or ArSH by reaction with Cl₂/KF

or CsF and subsequent transformation to ArSF₅by ZnF₂/

heat. The commercial availability of parent PhSF₅and a

few other derivatives, notably the p-Me, the p-NH₂, and the

m- and p-NO₂derivatives,^[8]has, to some extent, remedied

preparatory problems.

The strongly deactivating effect of SF₅group makes

PhSF₅amenable to S_NAr chemistry notably with alkoxides

and thiolate,^[9a]and by vicarious nucleophilic substitution

of hydrogen.^[9b–9d]By contrast, the S_EAr chemistry of SF₅-

aromatics has remained under-developed. In early work by

Philip et al.,^[4a]the 3-iodo and 4-iodo derivatives were syn-

thesized by in-situ diazotization and reaction with KI, and

were shown to enter into cross coupling reactions in repre-

Introduction

The presence of the pentafluorosulfanyl (SF₅) group im-

parts a number of favorable physical and chemical charac-

teristics including thermal, hydrolytic, and chemical sta-

bility, high density, high electronegativity, and high lipophil-

icity. These favorable characteristics have prompted a high

degree of interest in SF₅-organics for potential applications

in the biomedical and materials fields.^[1]

As a substituent on an aromatic ring the SF₅group acts

as a sterically demanding, strongly electron-withdrawing/

deactivating group. A major drawback in the development

of synthetic chemistry of SF₅-arenes has been the lack of

practical methods that avoid the use of exotic/hazardous

reagents and harsh conditions. In early pioneering studies

Sheppard synthesized the parent (pentafluorosulfanyl)benz-

[a] Department of Chemistry, University of North Florida, 1,

UNF Drive,

Jacksonville, Florida 32224, USA

E-mail: Kenneth.laali@UNF.edu

http://ww w .unf.edu/coas/chemistry/

[b] Department of Chemistry for Materials, Graduate School of

Engineering, Mie University,

Tsu 514-8507, Japan

[c] Department of Chemistry, Kent State University,

Kent, Ohio 44242, USA

Supporting information for this article is available on the

WWW under http://dx.doi.org/10.1002/ejoc.201301538

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Synthesis of Aromatic SF₅Compounds

sentative cases. Formation of an SF₅-based azo-dye by in- crystals did not diffract well enough to render viable crys-

situ diazotization and coupling to PhNMe₂was reported tallographic data.

+

by Kirsch and Hahn.^[4c]However, the F₅S–C₆H₄N₂salt

was never isolated in earlier studies to allow its use as a key

Heck–Matsuda Arylation

The p-SF₅substituted diazonium salt entered into Heck–

Matsuda coupling reaction with styrene and 4-substituted

styrenes in the presence of catalytic Pd(OAc)₂in ethanol to

give corresponding 4Ј-substituted 4-(pentafluorosulfan-

yl)stilbenes 2a–e (Table 1). Heck coupling in [BMIM][BF₄]

ionic liquid^[14]instead of EtOH resulted in lower isolated

yields due to the increased formation of homo-coupling

products (styrene dimer and oligomers) that could not be

effectively separated from the desired stilbene.

building block for the synthesis of other SF₅-aromatics

using diazonium ion chemistry.

In relation to our continuing interest in diazonium ion

chemistry and dediazoniation,^[10–13]and in the application

of ArN₂⁺in ligand coupling reactions,^[14]we report here on

the synthesis and isolation of 4-(pentafluorosulfanyl)

benzenediazonium tetrafluoroborate 1 as a stable salt.

Moreover, we explore the utility of 1 as a versatile building

block for the synthesis of a host of aromatic SF₅com-

pounds by cross coupling, azo-coupling, homocoupling, de-

diazoniation, and click chemistry.

Table 1. Heck–Matsuda arylation with styrenes.

Results and Discussion

Synthesis and Isolation of 4-(Pentafluorosulfanyl)phenyl-

diazonium Tetrafluoroborate (1)

In early trials diazonium salt 1 could not be isolated by

classical diazotization of the amine.^[15]Diazotization could

be effected by using NaNO₂/HBF₄but the resulting diazo-

nium salt would not precipitate out of solution following

dilution of the aqueous solution with ether, dichlorometh-

ane, or hexane. “Dry” diazotization as previously reported

by Doyle and Bryker,^[16]using tert-butyl nitrite/BF₃·OEt₂in

cold CH₂Cl₂(Figure 1), successfully afforded the diazo-

nium salt as a colorless precipitate which, following purifi-

cation with MeCN/ether, furnished the diazonium salt as a

pale-yellow solid. Tetrafluoroborate salt 1 is highly stable

and can be stored at room temperature for extended

periods. The ν_N–Nfrequency of 1 was observed at

2309 cm^–1, consistent with the extreme deactivating induc-

tive effect of the p-SF₅group. For comparison purposes it

is instructive to note that the ν_N–Nfrequency for 4-

R

Solvent

Temp. [°C] Time [h] Yield^[a][%]

H (2a)

F (2b)

CH₃(2c)

Cl (2d)

95% EtOH

[BMIM][BF₄]

95% EtOH

70

r.t.

70

r.t.

15

22

5

24

14

77

23

77

82

65

64

CH₃COO (2e)

[a] Isolated yield after SiO₂column chromatography.

Colorless crystals suitable for X-ray analysis were ob-

tained from 2e and the structure is shown in Figure 2. There

are three crystallographically unique molecules per unit cell

with an oxygen disordered over two positions in the third

molecule.

Diazonium salt 1 reacted with methyl acrylate in the

presence of Pd(OAc)₂in 95% EtOH to give methyl trans-3-

[4-(pentafluorosulfanyl)phenyl]prop-2-enoate 3 in 85% iso-

lated yield with no cis isomer being observed (Figure 3).

+

NO₂C₆H₄N₂is at 2280 cm^–1.^[17]Attempts were made to

obtain an X-ray structure for the diazonium salt but the

Figure 1. Synthesis of diazonium salts from 4-(pentafluorsulfanyl)-

aniline.

Figure 3. Heck coupling with methyl acrylate.

Figure 2. X-ray structure of 2e.

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T. Okazaki, K. K. Laali, S. D. Bunge, S. K. Adas

FULL PAPER

The coupling reaction with methyl methacrylate gave a

Attempted coupling of 7a with 1 in EtOH failed to pro-

mixture of two isomeric products namely methyl 2-methyl- duce the desired highly fluorinated adduct 8 even after stir-

3-[4-(pentafluorosulfanyl)phenyl]prop-2-enoate and ring for one week at room temp. or by heating at 70 °C

4

methyl 2-{[4-(pentafluorosulfanyl)phenyl]methyl}prop-2- (Figure 5).

enoate 5 in a 1:2 ratio in 78% isolated yield (Table 2). Opti-

mal yields were obtained after 18 h at room temp. in EtOH.

A near quantitative yield was reached at room temp. when

using [BMIM][BF₄] as the solvent although increased for-

mation of isomer 5 was also noted with these reaction con-

ditions.

Table 2. Heck–Matsuda arylation with methyl methacrylate.

Figure 5. Attempted synthesis of 8.

To further expand the scope of the Heck–Matsuda reac-

tion, coupling of 1 with camphene, norbornene, and trans-

stilbene was also investigated. Whereas coupling with

camphene afforded 9 in respectable isolated yield, com-

pound 10 could not be obtained by coupling to norbornene.

Coupling with trans-stilbene gave an inseparable isomeric

mixture of 11 and 12 (as indicated by NMR)^[18a](Table 4).

Solvent

Temp. [°C] Time [h] Ratio of 4/5 Yield^[a][%]

95% EtOH

[BMIM][BF₄]

70

r.t.

4

2

18

16

1:2

1:3

47%

78%

84%

99%

Table 4. Heck arylation with reactive alkenes.

[a] Combined yield after SiO₂column chromatography.

Attempted syntheses of 6 by Heck coupling of 1 with

ethyl cinnamate in EtOH, MeOH, or in [BMIM][BF₄] as

solvent at room temp. or by heating at 70 °C were unsuc-

cessful (Figure 4).

Figure 4. Attempted couplings with ethyl cinnamate.

In representative cases, diazonium salt 1 enabled cou-

pling with fluorous olefins to give novel polyfluorinated ad-

ducts 7a and 7b (Table 3).

[a] Isolated yield after SiO₂column chromatography.

Suzuki Coupling

Table 3. Heck arylation with fluoroalkenes.

In selected cases, diazonium salt 1 was allowed to react

with Ar-B(OH)₂under standard Suzuki coupling condi-

tions. These reactions yielded corresponding biaryl deriva-

tives 13a–c in isolated yields ranging from 27–59%

(Table 5).

Biaryl Synthesis by Homocoupling

R

Solvent

Temp. [°C] Time [h] Yield^[a][%]

The 1,4Ј-bis(pentafluorsulfanyl)biphenyl (14) was suc-

cessfully obtained in near quantitative yield by homocou-

pling using Pd(OAc)₂in MeOH solvent (Figure 6). It is

worth noting that Kirsch and Hahn accidentally obtained

compound 14 in 6% yield while attempting to metalate p-

BrC₆H₄SF₅with nBuLi/THF.^[4d]The X-ray structure of bi-

aryl species 14 is shown in Figure 7.

(CF₂)₃CF₃(7a)

(CF₂)₃CF₃(7a) [BMIM][BF₄]

(CF₂)₅CF₃(7b)

95% EtOH

r.t.

70

24

20

17

20

16

81%

69%

0%^[b]

13%^[b]

83%

95% EtOH

r.t.

[a] Isolated yield after SiO₂column chromatography. [b] After ex-

traction with hexane.

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Synthesis of Aromatic SF₅Compounds

Table 5. Suzuki-coupling with 1.

Halo-, Azido-, and Cyano-dediazoniation and Thiocyanation

in IL Solvent

Reaction of SF₅-diazonium salt 1 with TMSX (X = N₃,

I) and with NH₄SCN in [BMIM][BF₄] solvent provided

convenient access to compounds 16 through a dediazo-

niation route.^[13]Reaction with TMSBr, TMSCl, and

TMSCN/KF, on the other hand, generated only traces of

targeted SF₅compounds (Table 7). Fortunately, the X-ray

structure of thiocyanate derivative 16c was successfully ob-

tained and is shown in Figure 8.

R

Temp. [°C]

Time [h]

Yield^[a][%]

4-CF₃(13a)

3,4,5-F₃(13b)

3,5-Me₂(13c)

70

r.t.

3

24

20

27

44

59

[a] Isolated yield after SiO₂column chromatography.

Table 7. Reaction of 1 with TMSX (X = N₃, I, Br, Cl, CN) and

with NH₄SCN in [BMIM][BF₄].

Figure 6. Biaryl synthesis through homocoupling chemistry.

Sonogashira Coupling with Phenylacetylenes

Sonogashira coupling with phenylacetylene and its

mono- and bis-trifluoromethyl derivatives employing

Pd(OAc)₂/NaI^[18b]in 95% EtOH/Et₃N as solvent at 70 °C

resulted in modest isolated yields of adducts 15a–c

(Table 6). In control experiments no conversion was ob-

served in CH₃CN/Et₃N/PPh₃at 70 °C. Reactions using

EtOH alone or EtOH/Na₂CO₃at room temp. in the absence

of NaI also failed to afford the desired coupling products.

Table 6. Sonogashira coupling with phenylacetylenes.

[a] Isolated yield by SiO₂column chromatography. [b] Detected by

GC–MS.

Synthesis of the Triazole-Derivative by Click Chemistry

R

Solvent

Temp. [°C] Yield^[a][%]

Azide derivative 16a was found to take part in click

chemistry with phenylacetylene and its CF₃-substituted de-

rivatives when using Cu-Zn nanopowder as catalyst,^[19]to

give the corresponding triazole derivatives in isolated yields

ranging from 52–63% (Table 8).

H (15a)

2-CF₃(15b)

3,5-(CF₃)₂(15c) 95% EtOH, Et₃N

95% EtOH, Et₃N

70

9

15

17

[a] Isolated yield after SiO₂column chromatography.

Figure 7. X-ray structure of biaryl species 14.

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T. Okazaki, K. K. Laali, S. D. Bunge, S. K. Adas

FULL PAPER

EtOH solvent, simply by mixing at room temp. to give cor-

responding diazo derivatives 18 in 72–98% isolated yields

(Table 9). Coupling reactions with less reactive arenes

(phenol and aniline) were much slower and required pro-

longed reaction times. Attempted diazo-coupling with anis-

ole, 1-methylnaphthalene, 9-methylanthracene, anthracene,

2,6-lutidine, and benzyl cyanide under a variety of condi-

tions were unsuccessful.

Synthesis of Biaryls by Homolytic Dediazoniation

Homoytic dediazoniation can, in principle, serve as an

alternative route to Suzuki coupling for the synthesis of un-

symmetrical biaryls. Dediazoniation of 1 in MeCN/NaI^[20]

at room temperature in the presence of reactive arenes (mes-

itylene, p-xylene, and anisole) led to formation of desired

unsymmetrical SF₅-biaryls 19 in modest yields (Table 10).

Notably, formation of iodo derivatives 16b was a competing

reaction.

Figure 8. X-ray structure of the thiocyanate derivative 16c.

Table 8. Synthesis of triazole derivatives 17 by click chemistry.

Table 10. Synthesis of biaryl derivatives by homolytic dediazoni-

ation.

R

Yield of 19^[a]

2,4,6-Me₃(19a)

2,5-Me₂(19b)

2,3,5,6-Me₄(19c)

2,3,4,5,6-Me₅(19d)

MeO (19e)

31% (16b; 60%)

14% (16b; 14%)

R

Temp. [°C]

Time [h]

Yield^[a][%]

2%

H (17a)

2-CF₃(17b)

2,5-(CF₃)₂(17c)

70

19

52

65

63

trace^[b]

ortho (13%), meta (4%), para (5%)^[c]

Et (19f)

0%

[a] Isolated yield after SiO₂column chromatography.

[a] Isolated yield after SiO₂column chromatography. [b] GC–MS.

[c] As determined by NMR spectroscopy.

Diazonium Coupling

The SF₅-diazonium salt took part in azo-coupling chem-

istries with dimethoxy- and isomeric trimethoxybenzenes in

Dediazoniation Under Solvolytic Conditions

Table 9. Synthesis of diazo derivatives 18 by azo-coupling.

Solvolytic dediazoniation of 1 was studied in MeOH,

TFE, TfOH, TFAH, HFIP, and in [BMIM][X] ionic liquids

with X = PF₆, BF₄, and NTf₂as counterions, and the pro-

1

gress of each reaction was monitored by H and ¹⁹F NMR

spectroscopy.

Solvolysis in MeOH

R

Solvent

Temp. [°C]

Time

Yield^[a][%]

Diazonium salt 1 reacted slowly in MeOH at room tem-

perature to give Ph–SF₅as a major product along with p-

SF₅–C₆H₄OH and p-SF₅–C₆H₄OMe as minor products.

The rate of dediazoniation was found to increase in warm

MeOH; the reaction was nearly complete after 90 min. The

observed product distribution (Scheme 1) is consistent with

homolytic dediazoniation as the predominant mechanistic

pathway.^[21]

2,4-(MeO)₂(18a)

2,4,6-(MeO)₃(18b) 95% EtOH

2,4,5-(MeO)₃(18c) 95% EtOH

4-HO (18d)

4-NH₂(18e)

95% EtOH

r.t.

70

r.t.

2 weeks

6 min

16 h

1 month

20 d

98

75

72

0^[b]

62

22

CH₃CN

CH₃CN + AcONa

95% EtOH

[a] Isolated yield after SiO₂column chromatography. [b] NMR

monitoring.

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Eur. J. Org. Chem. 2014, 1630–1644

Synthesis of Aromatic SF₅Compounds

tant transformation of the SF₅moiety to SO₂F. Under these

conditions 22 was found to be generated cleanly (Ͼ95% by

NMR) and was isolated in quantitative yield. The results

are consistent with heterolytic dediazoniation in TFE and

in TfOH.

Solvolysis in TFAH

Solvolytic dediazoniation of 1 in TFAH was studied at

70 °C. Concomitant transformation of the SF₅moiety to its

SO₂F congener was again observed. The ester p-SF₅–C₆H₄-

OCOCF₃was not detected among the products. The evol-

ution of the solvolytic products, as monitored by NMR

(Scheme 3), suggests a heterolytic dediazoniation mecha-

nism and oxidation of the SF₅functionality to SO₂F as

major events.

Scheme 1. Dediazoniation in MeOH.

Solvolysis in TFE

Solvolysis of diazonium salt 1 in TFE was very slow at

room temperature; even after a reaction time of 7 d 94% of

1 remained unreacted. The rate of reaction could be im-

proved by heating at 70 °C (Scheme 2) for four hours. For-

mation of p-SF₅–C₆H₄-OCH₂CF₃20 and p-SF₅–C₆H₄-F 21

is consistent with heterolytic dediazoniation.^[22a]Com-

pound 20, the major product in the mixture, was obtained

in 29% isolated yield.

Scheme 3. Dediazoniation in TFAH.

Solvolysis in HFIP

Solvolysis of 1 in HFIP was very slow at room tempera-

ture. After stirring for 1 month p-SF₅–C₆H₄-OCH(CF₃)₂23

was detected by NMR together with unreacted 1. To speed

up the process, the reaction was followed at 60 °C where

competing oxidation led to a complex mixture which was

1

analyzed by H and ¹⁹F NMR (Scheme 4). The solvolytic

products observed in HFIP are in accord with a heterolytic

mechanism.

Scheme 2. Dediazoniation in TFE and TfOH.

Solvolysis in Ionic Liquids

Solvolytic dediazoniation in [BMIM][BF₄] and

[BMIM][PF₆] provides easy access to p-SF₅–C₆H₄-F 21

Solvolysis in TfOH

The diazonium salt remained unreacted in TfOH after through fluorodediazoniation.^[12]Reactions were performed

3 d of stirring at room temperature. However, dediazoni- at 50 °C and 70 °C and proceeded to completion within a

ation proceeded slowly at 50 °C over the course of 1 month matter of days. In line with related earlier studies,^[13]solvo-

to furnish triflate derivative 22 (Scheme 2), with concomi- lytic dediazoniaton of 1 in [BMIM][NTf₂] gave 25 as the

Scheme 4. Dediazoniation in HFIP.

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T. Okazaki, K. K. Laali, S. D. Bunge, S. K. Adas

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Figure 9. X-ray structure of the NTf₂adduct 26.

major and 26 as the minor trapping products consistent phenyl cation species, with R = NO₂, CF₃, and H (see Sup-

with the ambident nucleophilic character of NTf₂anion. porting Information).

Minor amounts of the fluorodediazoniation product p-SF₅–

C₆H₄-F 21 were also formed at higher temperatures

(Scheme 5).

Scheme 6. Isodesmic reaction.

Solvent effects were also considered using PCM calcula-

tions. The computed relative energies imply the relative sta-

+

bility order as Ph⁺ϾϾ p-CF₃C₆H₄Ͼ p-NO₂–C₆H₄≈ p-

+

F₅S-C₆H₄for the phenyl cation intermediates. In concert

with an earlier DFT study of aryl cations,^[22b]the singlet 4-

R-phenyl cations are more stable than the corresponding

triplet cations. Whereas a p-NO₂group is more effective in

stabilizing the singlet state relative to triplet state, a p-SF₅

group stabilizes the singlet and triplet phenyl cations to the

same extent.

Scheme 5. Dediazoniation in [BMIM][NTf₂].

Compound 25 was isolated as an oil, and attempts to

crystallize it were unsuccessful. By contrast, minor product

26 was isolated as a crystalline solid and its X-ray structure

successfully determined thus validating initial structure as-

signments (Figure 9).

Conclusions

Collectively, product analysis of dediazoniation reactions

with 1 in highly ionizing low nuclephilicity solvents (TFE,

The utility of 4-(pentafluorosulfanyl)phenyl diazonium

HFIP), protic acids (TfOH, TFAH) and imidazolium ionic tetrafluoroborate 1 as a versatile launch pad for the synthe-

liquids underscore the significance of heterolytic dediazoni- sis of a wide range of SF₅-aromatics through the applica-

ation and point to the involvement of SF₅–C₆H₄⁺as a criti- tion of diazonium ion chemistry that enables cross cou-

cal intermediate. Homolytic dediazoniation was found to be pling, azo-coupling, homocoupling, dediazoniation and

significant only in the MeOH case.

click chemistry has been demonstrated. Significantly, the

To elucidate the relative stability of p-SF₅–C₆H₄⁺the iso- present approach has potential to significantly expand the

desmic reaction (Scheme 6) was determined by DFT calcu- library of SF₅-aromatics for further applications in the bio-

lations at various levels for both the singlet and triplet medical and materials fields.

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Eur. J. Org. Chem. 2014, 1630–1644

Synthesis of Aromatic SF₅Compounds

8.8, 5.4 Hz, 2 H), 7.15 (d, J = 16.4 Hz, 1 H), 7.08 (d, J = 8.7 Hz,

2 H), 7.01 (d, J = 16.4 Hz, 1 H) ppm. ¹³C NMR (125 MHz,

CDCl₃): δ = 162.8 (C), 152.3 (C), 140.4 (C), 132.6 (C), 130.7 (CH),

128.4 (2CH), 126.3 (2CH), 126.2 (2CH), 126.2 (CH), 115.8

(2CH) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 84.9 (quint, J =

150.2 Hz, 1 F), 63.0 (d, J = 150.2 Hz, 4 F), –112.7 (m, 1 F) ppm.

Experimental Section

General: NMR spectra were recorded with a 500 MHz spectrome-

ter at room temperature (¹H: 500 MHz, ¹⁹F: 470 MHz, ¹³C:

125 MHz). IR data were collected with an FT-IR instrument. Elec-

tron ionization mass spectra (EI-MS) were measured using a GC–

MS instruments. All reagents were commercially available and were

used without purification.

(E)-4-Methyl-4Ј-(pentafluorosulfanyl)stilbene (2c): A solution of 1

(10.0 mg, 0.0315 mmol) in 0.4 mL of 95% aqueous ethanol was

4-(Pentafluorosulfanyl)benzenediazonium Tetrafluoroborate (1): A

solution of 1-(pentafluorosulfanyl)benzene (495.9 mg, 2.263 mmol)

in CH₂Cl₂(10 mL) was added dropwise to BF₃·OEt₂(493.3 mg,

3.476 mmol) in a flask cooled with an ice-water bath. tert-Butyl

nitrite (300.1 mg, 2.910 mmol) in 2 mL of CH₂Cl₂was added drop-

wise and stirred at 0 °C for 1 h. The precipitated colorless crystals

were isolated by filtration. The crystals was dissolve in CH₃CN

(0.4 mL) and precipitated by addition of ether to give pale yellow

solid crystals, which were washed with diethyl ether. Removal of the

solvent under vacuum afforded the title compound as pale yellow

added dropwise to

a solution of 4-methylstyrene (9.0 mg,

0.076 mmol) and palladium(II) acetate (0.2 mg, 0.0009 mmol) in

0.12 g of 95% aqueous ethanol. The reaction mixture was heated

on an oil bath at 70 °C for 5 h. After cooling, the mixture was

filtered through a pad of Celite 545 and purified by SiO₂column

chromatography (9:1 hexane/CH₂Cl₂) to give 2c (8.3 mg, 82%

yield) as colorless crystals; m.p. 165.2–166.5 °C. IR (ATR): ν =

˜

1593, 1514, 1450, 1416, 1329, 1265, 1098, 972, 962, 841 cm^–1. MS

(GC, EI): m/z = 320 [M⁺], 193 [M⁺– F₅S], 178 [M⁺– CH₃F₅S].

¹H NMR (500 MHz, CDCl₃): δ = 7.72 (d, J = 8.8 Hz, 2 H), 7.54

(d, J = 8.5 Hz, 2 H), 7.43 (d, J = 8.1 Hz, 2 H), 7.19 (d, J = 8.0 Hz,

2 H), 7.16 (d, J = 16.4 Hz, 1 H), 7.04 (d, J = 16.4 Hz, 1 H), 2.38

(s, 3 H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 152.3 (C), 140.8

(C), 138.6 (C), 133.6 (C), 131.9 (CH), 129.5 (2CH), 126.7 (2CH),

126.3 (2CH), 126.2 (2CH), 125.3 (CH), 21.3 (CH₃) ppm. ¹⁹F NMR

(470 MHz, CDCl₃): δ = 85.1 (quint, J = 150 Hz, 1 F), 63.1 (d, J =

150 Hz, 4 F) ppm.

crystals (605.1 mg, 84%): IR (ATR): ν = 2924, 2852, 2309, 1574,

˜

1418, 1304, 1053, 768 cm^–1. ¹H NMR (500 MHz, CD₃CN): δ =

8.72 (d, J = 9.2 Hz, 2 H), 8.40 (d, J = 9.2 Hz, 2 H) ppm. ¹³C NMR

(125 MHz, CD₃COCD₃): δ = 160.4, (C), 134.4 (2CH), 129.5 (2CH),

120.4 (C) ppm. ¹⁹F NMR (470 MHz, CD₃CN): δ = 77.7 (quint, J

= 151 Hz, 1 F), 60.9 (d, J = 151 Hz, 4 F), –151.5 (s, 4 F) ppm.

(E)-4-(Pentafluorosulfanyl)stilbene 2a. i) EtOH as Solvent: A solu-

tion of 1 (10.0 mg, 0.0315 mmol) in 0.4 mL of 95% aqueous eth-

anol was added dropwise to a solution of styrene (6.5 mg,

0.062 mmol) and palladium(II) acetate (0.5 mg, 0.002 mmol) in

0.11 g of 95% aqueous ethanol. The reaction mixture was heated

by an oil bath at 70 °C for 15 h. After cooling, the mixture was

filtered through a pad of Celite 545 and purified by SiO₂column

chromatography (9:1 hexane/CH₂Cl₂) to give 2a (7.4 mg, 77%

(E)-4-Chloro-4Ј-(pentafluorosulfanyl)stilbene (2d): Palladium(II)

acetate (0.5 mg, 0.002 mmol) was added to a solution of 1

(10.76 mg,

0.0337 mmol)

and

4-chlorostyrene

(19.0 mg,

0.137 mmol) in 0.18 g of 95% aqueous ethanol. The reaction mix-

ture was stirred at room temperature for 1 d. The mixture was fil-

tered through a pad of Celite 545 with CH₂Cl₂and purified by

SiO₂column chromatography with hexane as eluent to give 2d

(7.5 mg, 65% yield) as colorless crystals; m.p. 119.8–120.8 °C. MS

(GC, EI): m/z = 340 [M⁺], 321, 232, 213, 196, 178 [M⁺ClF₅S].

yield) as colorless crystals; m.p. 121.6–122.0 °C. IR (ATR): ν =

˜

3028, 1593, 1499, 1450, 1096, 964 cm^–1. MS (GC, EI): m/z = 306

1

[M⁺], 179. H NMR (500 MHz, CDCl₃): δ = 7.73 (d, J = 8.5 Hz,

IR (ATR): ν = 1589, 1495, 1414, 1094, 970, 831 cm^–1. ¹H NMR

˜

2 H), 7.56 (d, J = 8.5 Hz, 2 H), 7.53 (d, J = 7.4 Hz, 2 H), 7.39 (t,

J = 7.4 Hz, 2 H), 7.31 (t, J = 7.4 Hz, 1 H), 7.19 (d, J = 16.4 Hz, 1

H), 7.09 (d, J = 16.4 Hz, 1 H) ppm. ¹³C NMR (125 MHz, CDCl₃):

δ = 152.5 (C), 140.6 (C), 136.4 (C), 132.0 (CH), 128.8 (2CH), 128.5

(CH), 126.8 (2CH), 126.3 (5CH) ppm. ¹⁹F NMR (470 MHz,

CDCl₃): δ = 89.9 (quint, J = 150.2 Hz, 1 F), 61.0 (d, J = 150.2 Hz,

4 F) ppm.

(500 MHz, CDCl₃): δ = 7.73 (d, J = 8.7 Hz, 2 H), 7.55 (d, J =

8.7 Hz, 2 H), 7.46 (d, J = 8.5 Hz, 2 H), 7.35 (d, J = 8.5 Hz, 2 H),

7.13 (d, J = 16.4 Hz, 1 H), 7.06 (d, J = 16.4 Hz, 1 H) ppm. ¹³C

NMR (125 MHz, CDCl₃): δ = 152.7 (C), 140.2 (C), 134.9 (C), 134.1

(C), 130.6 (CH), 129.0 (2CH), 128.0 (2CH), 126.9 (CH), 126.4

(4CH) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 84.8 (quint, J =

150 Hz, 1 F), 63.0 (d, J = 150 Hz, 4 F) ppm.

ii) [BMIM][BF₄] as Solvent: Palladium(II) acetate (0.5 mg,

0.002 mmol) was added to a solution of 1 (10.5 mg, 0.0330 mmol)

and styrene (29.0 mg, 0.278 mmol) in 96.6 mg of [BMIM][BF₄].

The mixture was stirred at room temp. for 22 h and was extracted

with diethyl ether (0.5 mLϫ3). The solvent of the combined or-

ganic layer was evaporated to give a brown oil, which was purified

by SiO₂column chromatography (9:1 hexane/CH₂Cl₂) to give 2a

(2.3 mg, 23% yield) as colorless crystals.

(E)-4-Acetoxy-4Ј-(pentafluorosulfanyl)stilbene (2e): Palladium(II)

acetate (0.5 mg, 0.002 mmol) was added to a solution of 1 (11.6 mg,

0.0365 mmol) and 4-acetoxystyrene (11.5 mg, 0.0709 mmol) in

0.22 g of 95% aqueous ethanol. The reaction mixture was stirred

at room temperature for 14 h, filtered through a pad of Celite 545

with CH₂Cl₂, and purified by SiO₂column chromatography (1:1

hexane/CH₂Cl₂) to give 2e (8.5 mg, 64% yield) as colorless crystals;

m.p. 177.5–178.5 °C. MS (GC, EI): m/z = 364 [M⁺], 322 [M⁺

–

COCH ], 194, 165. IR (ATR): ν = 1759, 1593, 1508, 1373, 1223,

˜

2

(E)-4-Fluoro-4Ј-(pentafluorosulfanyl)stilbene (2b): A solution of 1

(10.4 mg, 0.0315 mmol) in 0.4 mL of 95% aqueous ethanol was

833 cm^–1. H NMR (500 MHz, CDCl₃): δ = 7.73 (d, J = 8.7 Hz, 2

1

H), 7.55 (d, J = 8.4 Hz, 2 H), 7.54 (d, J = 8.7 Hz, 2 H), 7.16 (d, J

= 16.4 Hz, 1 H), 7.12 (d, J = 8.4 Hz, 2 H), 7.04 (d, J = 16.4 Hz, 1

H), 2.32 (s, 3 H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 169.4

(C), 152.6 (C), 150.7 (C), 140.4 (C), 134.2 (C), 130.9 (CH), 127.8

(2CH), 126.6 (CH), 126.3 (4CH), 122.0 (2CH), 21.1 (CH₃) ppm.

¹⁹F NMR (470 MHz, CDCl₃): δ = 84.9 (quint, J = 150 Hz, 1 F),

63.1 (d, J = 150 Hz, 4 F) ppm.

added dropwise to

a solution of 4-fluorostyrene (9.8 mg,

0.080 mmol) and palladium(II) acetate (0.2 mg, 0.0009 mmol) in

0.10 g of 95% aqueous ethanol. The reaction mixture was heated

on an oil bath at 70 °C for 5 h. After cooling, the mixture was

filtered through a pad of Celite 545 and purified by SiO₂column

chromatography (9:1 hexane/CH₂Cl₂) to give 2b (8.2 mg, 77%

yield) as colorless crystals; m.p. 85.0–86.2 °C. IR (ATR): ν = 1593,

˜

1508, 1236, 1159, 1099, 964, 831, 818 cm^–1. MS (GC, EI): m/z =

324 [M⁺], 197 [M⁺SF₅], 177. ¹H NMR (500 MHz, CDCl₃): δ =

7.73 (d, J = 8.8 Hz, 2 H), 7.55 (d, J = 8.5 Hz, 2 H), 7.51 (dd, J =

Methyl (E)-3-[4-(Pentafluorosulfanyl)phenyl]prop-2-enoate (3):^[4a]

Palladium(II) acetate (0.5 mg, 0.002 mmol) was added to a solution

of

1

(10.9 mg, 0.0343 mmol) and methyl acrylate (15.6 mg,

Eur. J. Org. Chem. 2014, 1630–1644

www.eurjoc.org

1637

T. Okazaki, K. K. Laali, S. D. Bunge, S. K. Adas

FULL PAPER

0.181 mmol) in 0.18 g of 95% aqueous ethanol. The reaction mix-

ture was stirred at room temperature for 18 h, filtered through a

pad of Celite 545 with CH₂Cl₂, and purified by SiO₂column

chromatography (6:4 hexane/CH₂Cl₂) to give 3 (8.4 mg, 85% yield)

as colorless crystals; m.p. 80.5–81.5 °C. MS (GC, EI): m/z = 288

Methyl 2-{[4-(Pentafluorosulfanyl)phenyl]methyl}prop-2-enoate (5):

IR (ATR): ν = 2955, 1721, 1632, 1441, 1207, 1142, 1099, 840 cm^–1.

˜

MS (GC, EI): m/z = 302 [M⁺], 116 [M⁺– C₂H₃F₅O₂S], 115 [M⁺

–

C₂H₄F₅O₂S]. ¹H NMR (500 MHz, CDCl₃): δ = 7.77 (d, J = 8.5 Hz,

2 H), 7.66 (s, 1 H), 7.45 (d, J = 8.5 Hz, 2 H), 3.84 (s, CH₃), 2.11

(s, CH₃) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 166.9 (C), 152.3

(C), 142.8 (C), 138.9 (C), 129.1 (2CH), 127.2 (CH₂), 126.0

[M⁺], 269 [M⁺– F], 257, 130, 102. IR (ATR): ν = 1701, 1640, 1439,

˜

1317, 1213, 1101, 999, 845, 816 cm^–1. ¹H NMR (500 MHz, CDCl₃):

δ = 7.78 (d, J = 8.7 Hz, 2 H), 7.68 (d, J = 16.1 Hz, 1 H), 7.60 (d, (2CH) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 84.1 (quint, J =

J = 8.7 Hz, 2 H), 7.61 (d, J = 16.1 Hz, 1 H), 3.83 (s, 3 H) ppm.

¹³C NMR (125 MHz, CDCl₃): δ = 166.7 (C), 154.6 (C), 142.5 (CH),

137.5 (C), 128.0 (2CH), 126.6 (2CH), 121.1 (CH), 52.0 (CH₃) ppm.

¹⁹F NMR (470 MHz, CDCl₃): δ = 83.7 (quint, J = 150 Hz, 1 F),

62.6 (d, J = 150 Hz, 4 F) ppm.

150.2 Hz, 1 F), 62.8 (d, J = 150.2 Hz, 4 F) ppm.

(E)-3,3,4,4,5,5,6,6,6-Nonafluoro-1-[4-(pentafluorosulfanyl)phenyl]-

hex-1-ene (7a): Palladium(II) acetate (0.5 mg, 0.002 mmol) was

added to a solution of 1 (15. 0 mg, 0. 0472 mmol) and

3,3,4,4,5,5,6,6,6-nonafluorohex-1-ene (8.9 mg, 0.089 mmol) in

0.44 g of 95% aqueous ethanol. The reaction mixture was stirred

at room temperature for 1 d and filtered through a pad of Celite

545. Removal of the solvent gave a pale yellow oil which was puri-

fied by SiO₂column chromatography with hexane to give 7a as

Methyl (E)-2-Methyl-3-(pentafluorosulfanyl)prop-2-enoate

4 and

Methyl 2-{[4-(Pentafluorosulfanyl)phenyl]methyl}prop-2-enoate (5):

i) In EtOH. Method a: A solution of 1 (10.2 mg, 0.0321 mmol) in

0.4 mL of 95% aqueous ethanol was added dropwise to a solution

of methyl methacrylate (8.9 mg, 0.089 mmol) and palladium(II)

acetate (0.2 mg, 0.0009 mmol) in 0.12 g of 95% aqueous ethanol.

The reaction mixture was heated on an oil bath at 70 °C for 4 h.

After cooling, the mixture was filtered through a pad of Celite 545.

Removal of the solvent gave a brown oil, whose NMR analysis

showed the formation of 4 and 5 in 1: 2 ratio (17.8 mg). The prod-

ucts were purified by SiO₂column chromatography (6:4 hexane/

CH₂Cl₂). The first eluted product was 5 (colorless oil; 1.2 mg,

12%). The second fraction was a mixture of 5 and 4 (pale yellow

oil; 1:1 ratio, 2.8 mg, 29%), and the next fraction was pure 4 (pale

yellow oil; 0.6 mg, 6%).

colorless oil (17.1 mg; 81%): IR (ATR): ν = 2918, 2849, 1663, 1234,

˜

1134, 844 cm^–1. MS (GC, EI): m/z = 448 [M⁺], 429 [M⁺– F], 302

[M⁺– SF₆], 279 [M⁺– C₃F₇], 152 [M⁺– C₃F₁₂S]. ¹H NMR

(500 MHz, CDCl₃): δ = 7.80 (d, J = 8.7 Hz, 2 H), 7.57 (d, J =

8.7 Hz, 2 H), 7.20 (d, J = 16.2 Hz, 1 H), 6.30 (dt, J = 16.2, 12.0 Hz,

1 H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 154.7 (C), 137.7

(CH), 136.5 (C), 127.8 (2CH), 126.7 (2CH), 117.7 (CH) ppm. ¹⁹F

NMR (470 MHz, CDCl₃): δ = 83.4 (quint, J = 150 Hz, 1 F), 62.6

(d, J = 150 Hz, 4 F), –81.0 (s, 3 F), –112.0 (s, 2 F), –124.0 (s, 2 F),

–125.7 (s, 2 F) ppm.

(E)-3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluoro-1-[4Ј-(pentafluorothio)-

phenyl]oct-1-ene (7b): Palladium(II) acetate (1.0 mg, 0.0045 mmol)

was added to a solution of 1 (22.4 mg, 0.0704 mmol) and

3,3,4,4,5,5,6,6,7,7,8,8,8-undecacfluorooct-1-ene (35.4 mg,

0.102 mmol) in 0.45 g of 95% aqueous ethanol. The reaction mix-

ture was stirred at room temperature for 16 h, and filtered through

a pad of Celite 545 with a help of hexane. Removal of the solvent

gave a pale brown oil, which was purified by SiO₂column

chromatography with hexane to give 7b as colorless oil (31.9 mg;

Method b: To a solution of 1 (20.8 mg, 0.0654 mmol) and methyl

methacrylate (19.0 mg, 0.190 mmol) in 0.76 g mL of 95% aqueous

ethanol was added palladium(II) acetate (0.5 mg, 0.002 mmol). The

reaction mixture was heated on an oil bath at 70 °C for 2 h. After

cooling, the mixture was filtered through a pad of Celite 545 to

give a pale brown oil, whose NMR analysis showed the formation

of 4 and 5 in 1:2 ratio (32.7 mg). The products were purified by

SiO₂column chromatography (7:3 hexane/CH₂Cl₂) to give a mix-

ture of both compounds (15.5 mg) as colorless oil (78%). Subse-

quent preparative TLC (1:1 hexane/CH₂Cl₂) separation of the mix-

ture gave: The first eluted product was 5 (colorless oil; 9.6 mg,

48%). The second fraction was a mixture of the two compounds

(pale yellow oil; 1:1 ratio, 11.1 mg, 56%) and the next fraction was

pure 4 (pale yellow oil; 1.8 mg, 9%).

83%): IR (ATR): ν = 1238, 1190, 1144, 844 cm^–1. MS (GC, EI):

˜

m/z = 548 [M⁺], 529 [M⁺– F], 421 [M⁺– SF₅], 402 [M⁺– SF₆], 279

1

[M⁺– C₅F₁₁], 152 [M⁺– C₅F₁₆S]. H NMR (500 MHz, CDCl₃): δ

= 7.80 (d, J = 8.6 Hz, 2 H), 7.57 (d, J = 8.6 Hz, 2 H), 7.20 (d, J =

16.2 Hz, 1 H), 6.30 (dt, J = 16.2, 11.8 Hz, 1 H) ppm. ¹³C NMR

(125 MHz, CDCl₃): δ = 154.7 (C), 137.6 (CH), 136.6 (C), 127.8

(2CH), 126.7 (2CH), 117.8 (CH) ppm. ¹⁹F NMR (470 MHz,

CDCl₃): δ = 83.4 (quint, J = 150 Hz, 1 F), 62.6 (d, J = 150 Hz, 4

F), –80.8 (s, 3 F), –111.8 (s, 2 F), –121.6 (s, 2 F), –122.9 (s, 2 F),

–123.2 (s, 2 F), –126.2 (s, 2 F) ppm.

ii) in [BMIM][BF₄]: To a solution of 1 (11.3 mg, 0.0355 mmol) and

methyl methacrylate (20.0 mg, 0.200 mmol) in 0.11 g of

[BMIM][BF₄] was added palladium(II) acetate (0.5 mg,

0.002 mmol). The reaction mixture was stirred at room temp. for

16 h. NMR analysis of the reaction mixture showed the formation

of 4 and 5 in 1:3 ratio and complete consumption of the diazonium

ion. The reaction mixture was extracted with diethyl ether and the

solvent was evaporated to give a pale-brown oil. The products were

purified by SiO₂column chromatography (8:2 hexane/CH₂Cl₂) to

give a mixture of the two compounds (10.6 mg) as colorless oil

(99%).

Camphene Adduct 9: Palladium(II) acetate (0.3 mg, 0.001 mmol)

was added to a solution of 1 (12.9 mg, 0.0406 mmol) and camphene

(7.7 mg, 0.057 mmol) in 0.27 g of 95% aqueous ethanol. The reac-

tion mixture was stirred at room temperature for 16 h, and filtered

through a pad of Celite 545 with the help of hexane. Removal of

the solvent gave a colorless oil, which was purified by SiO₂column

chromatography using hexane to give the adduct 9 as colorless oil

Methyl 2-Methylidene-3-(pentafluorosulfanyl)propanoate (4): IR

(12.2 mg; 89%): IR (ATR): ν = 2965, 1655, 1597, 1495, 1460, 1383,

˜

(ATR): ν = 2916, 2849, 1717, 1439, 1261, 1117, 847 cm^–1. MS (GC,

1101, 841 cm^–1. MS (GC, EI): m/z = 338 [M⁺], 323 [M⁺– CH₃],

˜

EI): m/z = 302 [M⁺], 242 [M⁺– C₂H₄O₂], 115 [M⁺– C₂H₄F₅O₂S].

¹H NMR (500 MHz, CDCl₃): δ = 7.67 (d, J = 8.5 Hz, 2 H), 7.30

(d, J = 8.5 Hz, 2 H), 6.29 (s, 1 H), 5.56 (s, 1 H), 3.74 (s, 3 H), 3.68

(s, 2 H) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 85.3 (quint, J =

150.2 Hz, 1 F), 63.2 (d, J = 150.2 Hz, 4 F) ppm. ¹³C NMR

309 [M⁺– C₂H₅]. H NMR (500 MHz, CDCl₃): δ = 7.67 (d, J =

1

8.8 Hz, 2 H), 7.30 (d, J = 8.8 Hz, 2 H), 6.00 (s, 1 H), 3.21 (d, J =

4.7 Hz, 1 H), 1.99 (d, J = 2.2 Hz, 1 H), 1.84 (m, 1 H), 1.76 (m, 1

H), 1.72 (m, 1 H), 1.51 (m, 1 H), 1.41 (m, 1 H), 1.30 (d, J = 10.0 Hz,

1 H), 1.13 (s, 6 H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 163

(125 MHz, CDCl₃): δ = 168.5 (C), 153.1 (C), 139.2 (C), 136.5 (CH), (C), 151.0 (C), 142.5 (C), 127.8 (2CH), 125.7 (2CH), 114.7 (CH),

131.1 (C), 129.6 (2CH), 126.0 (2CH) ppm. 47.4 (CH), 43.6 (C), 42.6 (CH), 38.0 (CH₂), 28.9 (CH₃), 27.7 (CH₂),

1638

www.eurjoc.org

Eur. J. Org. Chem. 2014, 1630–1644

Synthesis of Aromatic SF₅Compounds

26.1 (CH₃), 23.7 (CH₂) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = = 83.9 (quint, J = 150 Hz, 1 F), 63.0 (d, J = 150 Hz, 4 F), –132.9

85.6 (quint, J = 150 Hz, 1 F), 63.2 (d, J = 150 Hz, 4 F) ppm.

(d, J = 8 Hz, 2 F), –160.3 (t, J = 8 Hz, 1 F) ppm.

3,5-Dimethyl-4Ј-(pentafluorosulfanyl)biphenyl (13c): Palladium(II)

acetate (0.5 mg, 0.002 mmol) was added to a mixture of 1 (12.2 mg,

0.0384 mmol), 3,5-dimethylphenylboronic acid (5.2 mg,

0.035 mmol), and Na₂CO₃(6.7 mg, 0.063 mmol) in 0.48 g of 95%

aqueous ethanol. The reaction mixture was stirred at room temp.

for 20 h and filtered through a pad of SiO₂with the help of hexane.

Removal of the solvent gave a brown crystalline solid which was

purified by SiO₂column chromatography with hexane to give 13c

Reaction with Stilbene: Palladium(II) acetate (0.5 mg, 0.002 mmol)

was added to a solution of 1 (11.1 mg, 0.0349 mmol) and stilbene

(8.0 mg, 0.044 mmol) in 0.21 g of 95% aqueous ethanol. The reac-

tion mixture was heated an oil bath at 70 °C for 40 min, and filtered

through a pad of Celite 545 with the help of hexane. Removal of

the solvent gave a colorless crystalline solid, which was purified by

SiO₂column chromatography using hexane/CH₂Cl₂(8:2) to give a

mixture of stilbene, and (Z)-, and (E)-1,2-diphenyl-1-(pentafluo-

rosulfanyl)phenylethenes (11 and 12) (5:2:3 ratio) as colorless crys-

tals (10.1 mg; yield of the adducts, 11 and 12, 45%).

(6.3 mg) as a colorless oil (59%): IR (ATR): ν = 3024, 2920, 2853,

˜

1599, 1468, 1379, 1105, 822 cm^–1. MS (GC, EI): m/z = 308 [M⁺],

293 [M⁺– CH₃], 289 [M⁺– F], 199, 203, 164. ¹H NMR (500 MHz,

CDCl₃): δ = 7.79 (d, J = 8.5 Hz, 2 H), 7.63 (d, J = 8.5 Hz, 2 H),

7.19 (s, 2 H), 7.06 (s, 1 H), 2.39 (s, 6 H) ppm. ¹³C NMR (125 MHz,

CDCl₃): δ = 152.8 (C), 144.8 (C), 139.1 (C), 138.6 (2 C), 130.0

(CH), 127.2 (2CH), 126.2 (2CH), 125.2 (2CH), 21.4 (2CH₃) ppm.

¹⁹F NMR (470 MHz, CDCl₃): δ = 84.9 (quint, J = 150 Hz, 1 F),

63.2 (d, J = 150 Hz, 4 F) ppm.

11: ¹H NMR (500 MHz, CDCl₃): δ = 7.69 (d, J = 8.5 Hz, 2 H),

7.40–7.26 (m, 6 H), 7.19–7.14 (m, 4 H), 7.05–7.02 (m, 2 H), 7.04

(s, 1 H) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 84.7 (quint, J =

150 Hz, 1 F), 63.0 (d, J = 150 Hz, 4 F) ppm. ¹³C NMR (125 MHz,

CDCl₃): δ = 144.2 (C), 142.5 (C), 140.6 (C), 136.6 (C), 130.9 (2CH),

129.8 (CH), 129.5 (2CH), 128.4 (2CH), 128.2 (2CH), 128.0 (CH),

127.6 (2CH), 127.3 (CH), 126.2 (2CH) ppm.

1,4Ј-Bis(pentafluorosulfanyl)biphenyl (14):^[4d]Palladium(II) acetate

(0.3 mg, 0.001 mmol) was added to a solution of 1 (14.5 mg,

0.0384 mmol) in 0.15 g of methanol. The reaction mixture was

stirred at 70 °C for 5.5 h and filtered through a pad of SiO₂with

the help of hexane. Removal of the solvent gave a colorless crystal-

line solid which was purified by SiO₂column chromatography with

hexane to give 14 (7.7 mg) as colorless crystals (99%); m.p. 196.0–

12: ¹H NMR (500 MHz, CDCl₃): δ = 7.68 (d, J = 8.5 Hz, 2 H),

7.40–7.26 (m, 6 H), 7.19–7.14 (m, 4 H), 7.05–7.02 (m, 2 H), 7.01

(s, 1 H) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 84.9 (quint, J =

150 Hz, 1 F), 63.1 (d, J = 150 Hz, 4 F) ppm. ¹³C NMR (125 MHz,

CDCl₃): δ = 146.7 (C), 140.6 (C), 139.3 (C), 136.6 (C), 130.5 (CH),

130.2 (2CH), 129.7 (2CH), 128.9 (2CH), 128.1 (2CH), 127.9 (CH),

127.6 (2CH), 127.4 (CH), 125.8 (2CH) ppm.

197.0 °C (in sealed tube). IR (ATR): ν = 3007, 2992, 1599, 1481,

˜

1391, 1277, 1260, 1101, 831, 810 cm^–1. MS (GC, EI): m/z = 406

[M⁺], 387 [M⁺– F], 282, 190. ¹H NMR (500 MHz, CDCl₃): δ =

7.87 (d, J = 8.6 Hz, 2 H), 7.66 (d, J = 8.6 Hz, 2 H) ppm. ¹³C NMR

(125 MHz, CDCl₃): δ = 153.7 (C), 142.3 (C), 127.6 (2CH), 126.7

(2CH) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 84.0 (quint, J =

150 Hz, 1 F), 63.0 (d, J = 150 Hz, 4 F) ppm.

4-(Pentafluorosulfanyl)-4Ј-(trifluoromethyl)biphenyl (13a): Palladi-

um(II) acetate (0.5 mg, 0.002 mmol) was added to a mixture of 1

(10.8 mg, 0.0340 mmol), 4-(trifluoromethyl)phenylboronic acid

(7.3 mg, 0.038 mmol), and Na₂CO₃(5.9 mg, 0.056 mmol) in 0.20 g

of 95% aqueous ethanol. The reaction mixture was stirred at 70 °C

for 3 h, and filtered through a pad of SiO₂with the help of hexane.

Removal of the solvent gave a brown crystalline solid, which was

purified by SiO₂column chromatography with hexane to give the

title compound 13a as colorless crystals (3.2 mg; 27%); m.p. 123.5–

1-(Pentafluorosulfanyl)-4-(phenylethynyl)benzene (15a):^[4a]Diazo-

nium salt 1 (11.7 mg, 0.0368 mmol) was added to a mixture of

phenylacetylene (11.4 mg, 0.0805 mmol), sodium iodide (9.8 mg,

0.065 mmol), and Pd(OAc)₂(0.5 mg, 0.002 mmol) in 0.23 g of 95%

ethanol. Then triethylamine (10.6 mg, 0.077 mmol) was added to

the mixture. The reaction mixture was stirred at 70 °C for 22 h,

then filtered through a pad of SiO₂with the help of hexane. Re-

moval of the solvent gave a pale yellow crystalline solid which were

purified by SiO₂column chromatography with hexane to give 15a

125.0 °C. IR (ATR): ν = 2924, 1618, 1492, 1395, 1327, 1171, 1107,

˜

1072, 837, 814 cm^–1. MS (GC, EI): m/z = 348 [M⁺], 329 [M⁺– F],

1

239. H NMR (500 MHz, CDCl₃): δ = 7.87 (d, J = 8.8 Hz, 2 H),

7.75 (d, J = 8.8 Hz, 2 H), 7.69 (d, J = 8.8 Hz, 2 H), 7.67 (d, J =

8.8 Hz, 2 H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 153.5 (C),

143.0 (C), 142.5 (C), 130.5 (q, J = 33 Hz), 127.7 (2CH), 127.5

(2CH), 126.6 (2CH), 126.0 (2CH), 124.0 (q, J = 272 Hz, C) ppm.

¹⁹F NMR (470 MHz, CDCl₃): δ = 84.2 (quint, J = 150 Hz, 1 F),

63.0 (d, J = 150 Hz, 4 F), –62.6 (s, 3 F) ppm.

as a colorless oil (1.0 mg; 9%); m.p. 88.0–89.0 °C. IR (ATR): ν =

˜

2926, 2222, 1603, 1503, 1445, 1402, 1094, 835 cm^–1. MS (GC, EI):

1

m/z = 304 [M⁺], 196. H NMR (500 MHz, CDCl₃): δ = 7.74 (d, J

= 9.0 Hz, 2 H), 7.60 (d, J = 9.0 Hz, 2 H), 7.55 (m, 2 H), 7.39–7.37

(m, 3 H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 153.0 (C), 131.8

(2CH), 131.6 (2CH), 129.0 (CH), 128.5 (2CH), 127.0 (C), 126.0

(2CH), 122.2 (C), 92.2 (C), 87.2 (C) ppm. ¹⁹F NMR (470 MHz,

CDCl₃): δ = 84.0 (quint, J = 150 Hz, 1 F), 62.7 (d, J = 150 Hz, 4

F) ppm.

3,4,5-Trifluoro-4Ј-(pentafluorosulfanyl)biphenyl (13b): Palladium(II)

acetate (0.5 mg, 0.002 mmol) was added to a mixture of 1 (14.7 mg,

0.0462 mmol), 3,4,5-trifluorophenylboronic acid (7.1 mg,

0.040 mmol), and Na₂CO₃(15.1 mg, 0.14 mmol) in 0.69 g of 95%

aqueous ethanol. The reaction mixture was stirred at room temp.

for 1 d, and filtered through a pad of SiO₂with the help of hexane.

Removal of the solvent gave a brown crystalline solid which was

purified by SiO₂column chromatography with hexane to give 13b

as a colorless oil (6.0 mg; 44%), which subsequently gave colorless

1-(Pentafluorosulfanyl)-4-[(2-trifluoromethyl)phenylethynyl]benzene

(15b): Sodium iodide (9.8 mg, 0.065 mmol) was added portion-wise

to a solution of 1 (10.4 mg, 0.0327 mmol) in 0.17 g of 95% ethanol.

To the mixture, triethylamine (7.8 mg, 0.077 mmol), (2-trifluoro-

crystals (from hexane); m.p. 46.5–48.8 °C. IR (ATR): ν = 1618,

˜

1579, 1537, 1506, 1496, 1449, 1396, 1363, 1254, 1105, 1051, methyl)phenylacetylene (13.7 mg, 0.0805 mmol), and Pd(OAc)₂

828 cm^–1. MS (GC, EI): m/z = 334 [M⁺], 315 [M⁺– F], 226, 206.

¹H NMR (500 MHz, CDCl₃): δ = 7.85 (d, J = 8.5 Hz, 2 H), 7.58

(d, J = 8.5 Hz, 2 H), 7.20 (t, J = 7.0 Hz, 2 H) ppm. ¹³C NMR

(125 MHz, CDCl₃): δ = 153.5 (C), 151.5 (d, J = 251 Hz, C), 141.4

(0.5 mg, 0.002 mmol) were subsequently added. The reaction mix-

ture was stirred at 70 °C for 4 h, then filtered through a pad of

SiO₂with the help of hexane. Removal of the solvent gave a brown

oil which was purified by SiO₂column chromatography with hex-

(C), 140.0 (d, J = 254 Hz, C), 135.0 (C), 127.1 (2CH), 126.8 (2CH), ane to give 15b as a colorless oil (1.8 mg; 15%): IR (ATR): ν =

˜

111.5 (d, J = 17 Hz, 2CH) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ

2232, 1605, 1503, 1323, 1261, 1175, 1134, 1111, 829 cm^–1. MS (GC,

Eur. J. Org. Chem. 2014, 1630–1644

www.eurjoc.org

1639

T. Okazaki, K. K. Laali, S. D. Bunge, S. K. Adas

EI): m/z = 372 [M⁺], 353 [M⁺– F], 264, 243. H NMR (500 MHz, NMR (470 MHz, CDCl₃): δ = 82.5 (quint, J = 151 Hz, 1 F), 62.9

FULL PAPER

1

CDCl₃): δ = 7.76 (d, J = 8.4 Hz, 2 H), 7.72 (d, J = 7.8 Hz, 1 H),

7.70 (d, J = 7.8 Hz, 1 H), 7.62 (d, J = 8.4 Hz, 6 H), 7.56 (t, J =

7.8 Hz, 1 H), 7.48 (t, J = 7.8 Hz, 1 H) ppm. ¹³C NMR (125 MHz,

CDCl₃): δ = 153.5 (C), 133.9 (C), 131.8 (q, J = 34 Hz, C), 131.7

(2CH), 131.5 (CH), 128.7 (CH), 126.4 (C), 126.1 (3CH), 123.4 (q,

J = 274 Hz, C), 120.5 (C), 92.5 (C), 88.1 (C) ppm. ¹⁹F NMR

(470 MHz, CDCl₃): δ = 83.8 (quint, J = 150 Hz, 1 F), 62.6 (d, J =

150 Hz, 4 F), –62.3 (s, 3 F) ppm.

(d, J = 151 Hz, 4 F) ppm.

Reaction of 1 with TMSCl: Trimethylsilyl chloride (6.0 mg,

0.055 mmol) was added to a solution of 1 (11.0 mg, 0.0346 mmol)

in [BMIM][BF₄] (62.1 mg). After stirring for 2 d the mixture was

extracted with hexane (0.5 mLϫ3) and the combined extracts was

analyzed by GC–MS to show the formation of small amount of:

16d:^[2,7]MS (GC, EI) m/z = 238 and 240 (M⁺), 221, 219, 132, 130.

Reaction of 1 with TMSBr: Trimethylsilyl bromide (9.8 mg,

0.064 mmol) was added to a solution of 1 (10.0 mg, 0.0315 mmol)

in [BMIM][BF₄] (57.4 mg). After stirring for 3 d the mixture was

extracted with hexane (0.5 mLϫ3) and the combined extracts was

analyzed by GC–MS to show the formation of 16e. The removal

of the solvent gave as 16e^[2,26,27]as a colorless oil (0.5 mg, 6%).

1-(Pentafluorosulfanyl)-4-[(3,5-trifluoromethyl)phenylethynyl]benz-

ene (15c): Sodium iodide (9.3 mg, 0.062 mmol) was added portion-

wise to a solution of 1 (15.4 mg, 0.0484 mmol) in 0.15 g of 95%

ethanol. To the mixture, triethylamine (10.0 mg, 0.0988 mmol), 3,5-

di(trifluoromethyl)phenylacetylene (15.1 mg, 0.0634 mmol), and

Pd(OAc)₂(0.3 mg, 0.001 mmol) were subsequently added. The re-

action mixture was stirred at 70 °C for 4 h, then filtered through a

pad of SiO₂with the help of hexane. Removal of solvent gave a

brown oil which was purified by SiO₂column chromatography with

Reaction of 1 with TMSCN/KF: Trimethylsilyl cyanide (10.8 mg,

0.109 mmol) and KF (3.5 mg, 0.060 mmol) were added to a solu-

tion of 1 (10.7 mg, 0.0337 mmol) in [BMIM][BF₄] (55.0 mg). After

stirring for 2 d the mixture was extracted with hexane (0.5 mLϫ3)

and the combined extracts was analyzed by GC–MS to show the

formation of small amount of 16f: MS (GC, EI): m/z = 229 [M⁺],

210 [M⁺– F], 121.

hexane to give 15c as a colorless oil (3.6 mg; 17%): IR (ATR): ν =

˜

2231, 1615, 1599, 1498, 1387, 1279, 1180, 1138, 833 cm^–1. MS (GC,

EI): m/z = 440 [M⁺], 421 [M⁺– F], 332. ¹H NMR (500 MHz,

CDCl₃): δ = 7.99 (s, 2 H), 7.87 (s, 1 H), 7.79 (d, J = 8.7 Hz, 2 H),

7.64 (d, J = 8.7 Hz, 2 H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 1-(4-Pentafluorosulfanyl)phenyl-4-phenyl-1H-1,2,3-triazole (17a):

153.8 (C), 132.1 (q, J = 34 Hz, 2 C), 131.9 (2CH), 131.6 (2CH),

126.3 (2CH), 125.5 (C), 124.7 (C), 122.8 (q, J = 273 Hz, C), 122.3

(CH), 90.4 (C), 88.8 (C) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ =

83.4 (quint, J = 150 Hz, 1 F), 62.6 (d, J = 150 Hz, 4 F), –63.1 (s,

6 F) ppm.

Cu-Zn (60/40) alloy nanopowder (Ͻ150 nm) (5.2 mg) was added

into a solution of 16c (7.2 mg, 0.033 mmol) and phenylethyne

(9.2 mg, 0.090 mmol). The mixture was heated at 70 °C for 19 h,

then cooled to room temp. and filtered through Celite with the

help of CH₂Cl₂. Evaporation of solvent produced a pale yellow

crystalline solid which was washed with hexane to give pale yellow

crystals of pure 17a (4.0 mg, 39%). The hexane solution was evapo-

rated to give a pale yellow oil which was purified by SiO₂column

chromatography with hexane/EtOAc (7:3) to furnish additional

amounts of 17a (colorless crystals; 1.3 mg, 13 %); m.p. 246.0–

4-(Pentafluorosulfanyl)phenyl Azide (16a):^[2]Trimethylsilyl azide

(6.5 mg, 0.056 mmol) was added to a solution of 1 (10.2 mg,

0.0321 mmol) in [BMIM][BF₄] (65.0 mg). After stirring for 5 min,

the mixture was extracted with hexane (0.5 mLϫ3) and the com-

bined extracts was evaporated to give pure 16a as a colorless oil

247.2 °C. IR (ATR): ν = 3123, 1596, 1504, 1483, 1458, 1436, 1410,

˜

(6.8 mg, 86 %): IR (ATR): ν = 2124, 2099, 1586, 1501, 1287,

˜

1230, 1101, 1089, 830 cm^–1. MS (GC, EI): m/z = 347 [M⁺], 319

843 cm^–1. MS (GC, EI): m/z = 245 [M⁺], 219 [M⁺– CN], 200 [M⁺

–

1

[M⁺– N₂], 211, 192, 165, 116, 90. H NMR (500 MHz, CDCl₃): δ

1

CFN], 111. H NMR (500 MHz, CDCl₃): δ = 7.74 (d, J = 9.0 Hz,

2 H), 7.08 (d, J = 9.0 Hz, 2 H) ppm. ¹³C NMR (125 MHz, CDCl₃):

δ = 150.3 (C), 143.3 (C), 127.7 (2CH), 118.9 (2CH) ppm. ¹⁹F NMR

(470 MHz, CDCl₃): δ = 84.4 (quint, J = 150 Hz, 1 F), 63.5 (d, J =

150 Hz, 4 F) ppm.

= 8.26 (s, 1 H), 7.98 (d, J = 9.8 Hz, 1 H), 7.95 (d, J = 9.8 Hz, 2

H), 7.93 (d, J = 7.3 Hz, 2 H), 7.49 (t, J = 7.3 Hz, 2 H), 7.41 (t, J

= 7.3 Hz, 1 H) ppm. ¹H NMR (500 MHz, [D₆]acetone): δ = 9.30

(s, 1 H), 8.28 (d, J = 9.2 Hz, 1 H), 8.20 (d, J = 9.2 Hz, 2 H), 8.03

(d, J = 7.6 Hz, 2 H), 7.52 (t, J = 7.6 Hz, 2 H), 7.43 (t, J = 7.6 Hz,

1 H) ppm. ¹³C NMR (125 MHz, [D₆]acetone): δ = 151.4 (C), 148.3

(C), 139.4 (C), 130.5 (C), 129.0 (2CH), 128.4 (CH), 128.0 (2CH),

125.6 (2CH), 120.3 (2CH), 118.9 (CH) ppm. ¹⁹F NMR (470 MHz,

CDCl₃): δ = 83.1 (quint, J = 150 Hz, 1 F), 63.1 (d, J = 150 Hz, 4

F) ppm. ¹⁹F NMR (470 MHz, [D₆]acetone): δ = 83.5 (quint, J =

148 Hz, 1 F), 62.6 (d, J = 148 Hz, 4 F) ppm.

1-Iodo-4-(pentafluorosulfanyl)benzene 16b:^[4a]Trimethylsilyl iodide

(15.0 mg, 0.0750 mmol) was added to a solution of 1 (11.0 mg,

0.0346 mmol) in [BMIM][BF₄] (67.6 mg). After stirring for 5 min

the mixture was extracted with hexane (0.5 mLϫ3) and the com-

bined extracts was evaporated to give pure 16b as a colorless oil

(4.6 mg, 40%): MS (GC, EI): m/z = 330 [M⁺], 311 [M⁺F], 222, 96.

¹H NMR (500 MHz, CDCl₃): δ = 7.82 (d, J = 8.8 Hz, 2 H), 7.48

(d, J = 8.8 Hz, 2 H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 137.9

(2CH), 127.5 (2CH), 98.2 (C) ppm. ¹⁹F NMR (470 MHz, CDCl₃):

δ = 83.5 (quint, J = 151 Hz, 1 F), 62.8 (d, J = 151 Hz, 4 F) ppm.

1-(4-Pentafluorosulfanyl)phenyl-4-[2-(trifluoromethyl)phenyl]-1H-

1,2,3-triazole (17b): Cu-Zn (60/40) alloy nanopowder (Ͻ150 nm)

(6.7 mg) was added to a solution of 16c (8.0 mg, 0.033 mmol) and

[2-(trifluoromethyl)phenyl]ethyne (10.1 mg, 0.0591 mmol). The

mixture was heated at 70 °C for 19 h, then cooled to room temp.

and filtered through Celite using CH₂Cl₂. Removal of solvent gave

a pale green oil, which was purified by SiO₂column chromatog-

raphy using hexane/EtOAc (8:2) to give 17b as colorless crystals

4-(Pentafluorosulfanyl)phenyl Thiocyanate (16c): A solution of am-

monium thiocyanate (7.3 mg, 0.096 mmol) and 1 (10.1 mg,

0.0318 mmol) in 0.29 g of MeCN was heated at 70 °C for 0.5 h.

After cooling, the mixture was filtered through SiO₂with CH₂Cl₂

and the solvent was evaporated to give a pale yellow oil, whose

purification by SiO₂column chromatography with 9:1 hexane/

CH₂Cl₂furnished pure 16c as colorless crystals (2.6 mg, 31%); m.p.

(9.1 mg, 65%); m.p. 92.5–93.0 °C. IR (ATR): ν = 1601, 1515, 1409,

˜

1315, 1177, 1125, 1036, 833 cm^–1. MS (GC, EI): m/z = 415 [M⁺],

396 [M⁺– F], 387 [M⁺– N₂], 368. ¹H NMR (500 MHz, CDCl₃): δ

= 8.26 (s, 1 H), 8.05 (d, J = 7.8 Hz, 1 H), 7.98 (d, J = 9.4 Hz, 2

H), 7.95 (d, J = 9.4 Hz, 2 H), 7.82 (d, J = 7.8 Hz, 1 H), 7.70 (t, J

= 7.6 Hz, 1 H), 7.56 (t, J = 7.6 Hz, 1 H) ppm. ¹³C NMR (125 MHz,

67.2–68.2 °C. IR (ATR): ν = 3103, 2162, 1585, 1479, 1402, 1105,

˜

1082, 837 cm^–1. MS (GC, EI): m/z = 261 [M⁺], 242 [M⁺– F], 153,

1

133. H NMR (500 MHz, CDCl₃): δ = 7.84 (d, J = 8.8 Hz, 2 H),

7.61 (d, J = 8.8 Hz, 2 H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = CDCl₃): δ = 153.3 (C), 145.5 (C), 138.6 (C), 132.2 (CH), 131.7

154.0 (C), 129.6 (C), 128.7 (2CH), 127.8 (2CH), 108.6 (C) ppm. ¹⁹

F

(CH), 128.9 (CH), 128.5 (C), 128.0 (2CH), 127.4 (q, J = 30 Hz, C),

1640

www.eurjoc.org

Eur. J. Org. Chem. 2014, 1630–1644

Synthesis of Aromatic SF₅Compounds

126.3 (CH), 124.1 (q, J = 274 Hz, C), 120.6 (CH), 120.3 3 H), 4.01 (s, 3 H), 3.93 (s, 3 H) ppm. ¹³C NMR (125 MHz,

(2CH) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 83.0 (quint, J =

150 Hz, 1 F), 63.1 (d, J = 150 Hz, 4 F), –58.6 (s, 3 F) ppm.

CDCl₃): δ = 154.74 (C), 154.70 (C), 154.3 (C), 154.0 (C), 144.1 (C),

135.1 (C), 126.9 (2CH), 122.4 (2CH), 98.8 (CH), 97.5 (CH), 57.6

(CH₃), 56.22 (CH₃), 56.17 (CH₃) ppm. ¹⁹F NMR (470 MHz,

CDCl₃): δ = 84.4 (quint, J = 150 Hz, 1 F), 63.3 (d, J = 150 Hz, 4

F) ppm.

1-(4-Pentafluorosulfanyl)phenyl-4-[3,5-bis(trifluoromethyl)phenyl]-

1H-1,2,3-triazole (17c): Cu-Zn (60/40) alloy nanopowder

(Ͻ150 nm) (6.9 mg) was added into a solution of 16c (5.5 mg,

0.022 mmol) and [3,5-bis(trifluoromethyl)phenyl]ethyne (10.2 mg, (E)-4-Hydroxy-4Ј-(pentafluorosulfanyl)azobenzene (18d): Diazo-

0.0428 mmol). The mixture was heated at 70 °C for 19 h, then co-

oled to room temp. and filtered through Celite using CH₂Cl₂. Re-

moval of the solvent gave a pale yellow oil, which was purified by

SiO₂column chromatography with hexane/EtOAc (8:2) to give 17c

as colorless crystals (6.9 mg, 63%); m.p. 169.0–169.5 °C. MS (GC,

EI): m/z = 483 [M⁺], 464 [M⁺– F], 455 [M⁺N₂], 348, 328. IR

nium salt 1 (11.6 mg, 0.0365 mmol), phenol (9.5 mg, 0.10 mmol),

and sodium acetate (10.2 mg, 0.124 mmol) were dissolved in 0.21 g

of acetonitrile. After 1 month, the solution was filtered through

Celite 545. Evaporation of the solvent gave a red oil, which was

purified by SiO₂column chromatography (9:1 hexane/ethyl acetate)

and following preparative TLC (SiO₂, CH₂Cl₂) afforded 18d as yel-

low-orange crystals (7.3 mg, 62%); m.p. 110.0–111.0 °C. IR (ATR):

(ATR): ν = 1669, 1601, 1514, 1373, 1330, 1278, 1177, 1134,

˜

1

833 cm^–1. H NMR (500 MHz, CDCl₃): δ = 8.44 (s, 1 H), 8.38 (s, ν = 3261, 1593, 1505, 1467, 1436, 1402, 1271, 1235, 1142, 1094,

˜

2 H), 8.01 (d, J = 9.3 Hz, 2 H), 7.97 (d, J = 9.3 Hz, 2 H), 7.90 (s,

1 H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 153.7 (C), 146.3 (C),

138.4 (C), 132.5 (q, J = 24 Hz, 2 C), 131.8 (C), 128.1 (2CH), 125.9

(2CH), 123.0 (q, J = 273 Hz, 2 C), 122.2 (CH), 120.2 (2CH), 118.4

(CH) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 82.7 (quint, J =

150 Hz, 1 F), 63.1 (d, J = 150 Hz, 4 F), –63.0 (s, 6 F) ppm.

829 cm^–1. MS (GC, EI): m/z = 324 [M⁺], 305 [M⁺– F], 197, 121,

1

93, 65. H NMR (500 MHz, CDCl₃): δ = 7.92–7.88 (m, 6 H), 6.97

(d, J = 8.8 Hz, 2 H), 5.50 (br. s, 1 H) ppm. ¹³C NMR (125 MHz,

CDCl₃): δ = 159.1 (C), 154.4 (C), 153.7 (C), 147.0 (C), 127.0 (2CH),

125.6 (2CH), 122.5 (2CH), 116.0 (2CH) ppm. ¹⁹F NMR (470 MHz,

CDCl₃): δ = 84.1 (quint, J = 150 Hz, 1 F), 63.2 (d, J = 150 Hz, 4

F) ppm.

(E)-2,4-Dimethoxy-4Ј-(pentafluorosulfanyl)azobenzene (18a): Di-

azonium salt 1 (9.8 mg, 0.030 mmol) in 1 mL of 95% aqueous eth-

anol was added to a solution of 1,3-dimethoxybenzene (8.7 mg,

0.063 mmol) in 0.5 mL of 95% aqueous ethanol. After 2 weeks, the

solvent was evaporated to give a red oil, whose purification by SiO₂

column chromatography (1:1 hexane/CH₂Cl₂) afforded 18a as

(E)-4-Amino-4Ј-(pentafluorosulfanyl)azobenzene (18e): Diazonium

salt 1 (11.1 mg, 0.0349 mmol) and aniline (32.0 mg, 0.344 mmol)

were dissolved in 0.19 g of 95% ethanol. After 20 d, the solution

was filtered through Celite 545. Evaporation of the solvent gave an

orange oil, which was purified by SiO₂column chromatography

(8:2 hexane/ethyl acetate) and following preparative TLC (SiO₂,

CH₂Cl₂) afforded 18e as orange crystals (2.5 mg, 22%); m.p. 153.0–

orange crystals (10.8 mg, 98%); m.p. 88.0–88.5 °C. IR (ATR): ν =

˜

2943, 1600, 1496, 1471, 1294, 1253, 1211, 767 cm^–1. MS (GC, EI):

1

m/z = 368 [M⁺], 241 [M⁺– SF₅], 165 [M⁺– C₆H₄SF₅]. H NMR

154.5 °C. IR (ATR): ν = 3417, 2915, 1666, 1628, 1603, 1507, 1398,

˜

1302, 1148, 1092, 834 cm^–1. MS (GC, EI): m/z = 323 [M⁺], 197,

(500 MHz, CDCl₃): δ = 7.89 (d, J = 9.0 Hz, 2 H), 7.86 (d, J =

9.0 Hz, 2 H), 7.78 (d, J = 9.0 Hz, 1 H), 6.60 (d, J = 2.4 Hz, 1 H),

6.56 (dd, J = 9.0, 2.4 Hz, 1 H), 4.03 (s, 3 H), 3.91 (s, 3 H) ppm.

¹³C NMR (125 MHz, CDCl₃): δ = 164.8 (C), 159.5 (C), 154.4 (C),

154.1 (C), 136.7 (C), 126.9 (2CH), 122.5 (2CH), 118.2 (CH), 105.9

(CH), 98.9 (CH), 56.3 (CH₃), 55.7 (CH₃) ppm. ¹⁹F NMR

(470 MHz, CDCl₃): δ = 84.3 (quint, J = 150 Hz, 1 F), 63.2 (d, J =

150 Hz, 4 F) ppm.

1

120, 94, 65. H NMR (500 MHz, CDCl₃): δ = 7.88–7.82 (m, 6 H),

6.76 (d, J = 8.8 Hz, 2 H), 2.20 (br. s, 1 H) ppm. ¹³C NMR

(125 MHz, CDCl₃): δ = 154.1 (C), 150.5 (C), 145.3 (C), 126.9

(2CH), 125.8 (2CH), 122.2 (2CH), 114.5 (2CH) ppm. ¹⁹F NMR

(470 MHz, CDCl₃): δ = 84.4 (quint, J = 150 Hz, 1 F), 63.2 (d, J =

150 Hz, 4 F) ppm.

2,4,6-Trimethyl-4Ј-(pentafluorosulfanyl)biphenyl (19a): Sodium iod-

ide (5.2 mg, 0.035 mmol) was added portion-wise to a solution of

1 (10.4 mg, 0.0327 mmol) and mesitylene (33.6 mg, 0.280 mmol) in

CH₃CN (0.14 g). The reaction mixture was filtered through Celite

545 by using CH₂Cl₂. The solvent was evaporated to give pale-red

oil. NMR analysis indicated the formation of a 2:1 mixture of 16b

and 19a which were separated by SiO₂column chromatography

using hexane to give 16b as colorless crystals (6.5 mg, 60%) and

19a as colorless crystals (3.3 mg, 31%).

(E)-2,4,6-Trimethoxy-4Ј-(pentafluorosulfanyl)azobenzene (18b): Di-

azonium salt 1 (11.9 mg, 0.0374 mmol) and 1,3,5-trimethoxybenz-

ene (6.6 mg, 0.039 mmol) were dissolved in 0.18 g of 95% aqueous

ethanol. After 0.1 h, a red solid precipitated which was filtered. The

red precipitate was purified by SiO₂column chromatography (7:3

hexane/ethyl acetate) to afford 18b as a red oil (11.2 mg, 75%): IR

(ATR): ν = 2943, 1599, 1456, 1335, 1207, 1151, 1126, 837 cm^–1.

˜

MS (GC, EI): m/z = 398 [M⁺], 271 [M⁺– SF₅], 195, 152. ¹H NMR

(500 MHz, CDCl₃): δ = 7.91 (d, J = 9.3 Hz, 2 H), 7.85 (d, J =

9.3 Hz, 2 H), 6.23 (s, 2 H), 3.93 (s, 6 H), 3.92 (s, 3 H) ppm. ¹³C

NMR (125 MHz, CDCl₃): δ = 164.4 (C), 156.4 (2 C), 154.6 (C),

153.9 (C), 127.1 (C), 126.9 (2CH), 122.0 (2CH), 91.4 (2CH), 56.6

(2CH₃), 55.7 (CH₃) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 84.5

(quint, J = 150 Hz, 1 F), 63.3 (d, J = 150 Hz, 4 F) ppm.

1

16b: H NMR (500 MHz, CDCl₃): δ = 7.82 (d, J = 8.8 Hz, 2 H),

7.48 (d, J = 8.8 Hz, 2 H) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ =

83.5 (quint, J = 150 Hz, 1 F), 62.8 (d, J = 150 Hz, 4 F) ppm.

19a: M.p. 121.8–122.8 °C. MS (GC, EI): m/z = 322 [M⁺], 307 [M⁺–

CH₃], 195 [M⁺– SF₅], 180 [M⁺– CH SF ]. IR (ATR): ν = 2292,

˜

3

5

1

1612, 1476, 1396, 1096, 765 cm^–1. H NMR (500 MHz, CDCl₃): δ

= 7.80 (d, J = 8.6 Hz, 2 H), 7.24 (d, J = 8.6 Hz, 2 H), 6.96 (s, 2

H), 2.34 (s, 3 H), 1.99 (s, 6 H) ppm. ¹³C NMR (125 MHz, CDCl₃):

δ = 152.4 (C), 145.0 (C), 137.4 (C), 136.9 (2 C), 135.6 (2CH), 129.7

(2CH), 128.3 (2CH), 126.1 (2CH), 21.0 (CH₃), 20.7 (2CH₃) ppm.

¹⁹F NMR (470 MHz, CDCl₃): δ = 85.0 (quint, J = 150 Hz, 1 F),

63.1 (d, J = 150 Hz, 4 F) ppm.

(E)-2,4,5-Trimethoxy-4Ј-(pentafluorosulfanyl)azobenzene (18c): Di-

azonium salt 1 (14.1 mg, 0.0443 mmol) and 1,2,4-trimethoxybenz-

ene (15.6 mg, 0.0928 mmol) were dissolved in 0.148 g of 95 %

aqueous ethanol. After 0.1 h, a red solid precipitated. After fil-

tration the red solid was purified by SiO₂column chromatography

(7:3 hexane/ethyl acetate) to give 18c as a red oil (12.8 mg, 72%):

IR (ATR): ν = 2941, 1607, 1598, 1505, 1472, 1436, 1269, 1209,

˜

1126, 1093, 1030, 839, 824 cm^–1. MS (GC, EI): m/z = 398 [M⁺],

2,5-Dimethyl-4Ј-(pentafluorosulfanyl)biphenyl (19b): Sodium iodide

140, 110. H NMR (500 MHz, CDCl₃): δ = 7.91 (d, J = 9.0 Hz, 2 (5.5 mg, 0.037 mmol) was added portion-wise to a solution of 1

1

H), 7.86 (d, J = 9.0 Hz, 2 H), 7.44 (s, 1 H), 6.64 (s, 1 H), 4.07 (s,

(9.9 mg, 0.031 mmol) and p-xylene (60.1 mg, 0.566 mmol) in

Eur. J. Org. Chem. 2014, 1630–1644

www.eurjoc.org

1641

T. Okazaki, K. K. Laali, S. D. Bunge, S. K. Adas

FULL PAPER

CH₃CN (0.11 g). The reaction mixture was filtered through Celite

545 using CH₂Cl₂. The solvent was evaporated to give a brown oil,

which was purified by SiO₂column chromatography with hexane

to afford 16b (1.4 mg, 14%) and 19b as a colorless oil (1.3 mg,

14%): MS (GC, EI): m/z = 308 [M⁺], 181 [M⁺– SF₅]. IR (ATR):

8.0, 2.0 Hz, 1 H), 3.88 (s, 3 H) ppm. ¹³C NMR (125 MHz, CDCl₃):

δ = 160.0 (C), 152.9 (C), 144.4 (C), 140.5 (C), 130.1 (CH), 127.3

(2CH), 126.4 (2CH), 119.7 (CH), 113.6 (CH), 113.2 (CH), 55.4

(CH₃) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 84.8 (quint, J =

150 Hz, 1 F), 63.1 (d, J = 150 Hz, 4 F) ppm.

ν = 2924, 1599, 1493, 1456, 1395, 1099, 833 cm^{–1 1}H NMR

.

˜

4-Methoxy-4Ј-(pentafluorosulfanyl)biphenyl (para): Colorless crys-

(500 MHz, CDCl₃): δ = 7.79 (d, J = 8.5 Hz, 2 H), 7.40 (d, J =

8.5 Hz, 2 H), 7.18 (d, J = 8.3 Hz, 1 H), 7.12 (d, J = 8.3 Hz, 1 H),

7.02 (s, 1 H), 2.36 (s, 3 H), 2.22 (s, 3 H) ppm. ¹³C NMR (125 MHz,

CDCl₃): δ = 155.0 (C), 145.6 (C), 139.5 (C), 132.0 (C), 130.5 (CH),

130.2 (CH), 129.4 (2CH), 128.8 (CH), 125.7 (2CH), 20.9 (CH₃),

19.8 (CH₃) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 84.9 (quint, J

= 150 Hz, 1 F), 63.2 (d, J = 150 Hz, 4 F) ppm.

tals; m.p. 102.0–104.0 °C. IR (ATR): ν = 2921, 2850, 1740, 1609,

˜

1493, 1467, 1398, 1298, 1261, 1184, 1103, 1037, 830 cm^–1. MS (GC,

EI): m/z = 310 [M⁺], 202, 187, 158, 139. ¹H NMR (500 MHz,

CDCl₃): δ = 7.79 (d, J = 8.8 Hz, 2 H), 7.61 (d, J = 8.8 Hz, 2 H),

7.53 (d, J = 8.8 Hz, 2 H), 7.00 (d, J = 8.8 Hz, 2 H), 3.87 (s, 3

H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 160.0 (C), 152.3 (C),

144.1 (C), 131.4 (C), 128.4 (2CH), 126.6 (2CH), 126.4 (2CH), 114.5

(2CH), 55.4 (CH₃) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 85.0

(quint, J = 150 Hz, 1 F), 63.2 (d, J = 150 Hz, 4 F) ppm.

2,3,5,6-Tetramethyl-4Ј-(pentafluorothio)biphenyl (19c): NaI (5.7 mg,

0.038 mmol) was added portion-wise to a solution of 1 (12.0 mg,

0.0377 mmol) and 1,2,4,5-tetramethylbenzene (8.6 mg,

0.064 mmol) in CH₃CN (0.17 g). The reaction mixture was filtered

through Celite 545 using CH₂Cl₂. The solvent was evaporated to

give (a) a mixture containing 1,2,4,5-tetramethylbenzene and 16b

(13.8 mg), and (b) the desired 19c as colorless crystals in very low

yield (0.3 mg, 2%).

Solvolytic Dediazoniations

i) In Methanol: Diazonium salt 1 (22.5 mg, 0.0314 mmol) was dis-

solved in methanol (0.82 mL). After 13 d stirring at room temp. a

portion of the solution was diluted with CDCl₃and analyzed by

NMR, which indicated the formation of 1-fluoro-4-(penta-

fluorosulfanyl)benzene 21,^[7]1-methoxy-4-(pentafluorosulfanyl)-

benzene,^[9a]and 4-(pentafluorosulfanyl)phenol.^[9a]

19c: M.p. 166.0–167.0 °C. MS (GC, EI): m/z = 336 [M⁺], 321 [M⁺–

CH₃], 194 [M⁺– CH SF ]. IR (ATR): ν = 2924, 2852, 1603, 1462,

˜

3

1

5

1096, 843, 810 cm^–1. H NMR (500 MHz, CDCl₃): δ = 7.81 (d, J

= 8.7 Hz, 2 H), 7.22 (d, J = 8.7 Hz, 2 H), 7.03 (s, 1 H), 2.27 (s, 6

H), 1.86 (s, 6 H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 152.3

(C), 146.2 (C), 140.0 (C), 133.8 (2 C), 131.5 (2 C), 131.1 (CH),

129.7 (2CH), 126.0 (2CH), 20.1 (CH₃), 17.2 (CH₃) ppm. ¹⁹F NMR

(470 MHz, CDCl₃): δ = 85.0 (quint, J = 150 Hz, 1 F), 63.2 (d, J =

150 Hz, 4 F) ppm.

4-(Pentafluorosulfanyl)phenol: Pale-brown oil. MS (GC, EI): m/z =

1

220 [M⁺], 201 [M⁺– F], 112, 84. H NMR (500 MHz, CDCl₃): δ

= 7.65 (d, J = 8.9 Hz, 2 H), 6.86 (d, J = 8.9 Hz, 2 H) ppm. ¹⁹F

NMR (470 MHz, CDCl₃): δ = 86.0 (quint, J = 150 Hz, 1 F), 64.2

(d, J = 150 Hz, 4 F) ppm.

ii) in 2,2,2-Trifluroethanol TFE: Diazonium salt 1 (24.1 mg,

0.0314 mmol) was dissolved in TFE (90.5 mg, 0.400 mmol) and the

mixture was heated at 70 °C for 4 h. NMR analysis of the reaction

mixture indicated the formation of 1-fluoro-4-(pentafluorosulf-

anyl)benzene (21),^[7]1-(pentafluorosulfanyl)-4-(2,2,2-trifluoro-

ethoxy)benzene (20),^[9a]and unreacted 1 in 39:56:5 ratio. Most of

the solvent was evaporated to give a pale yellow oil, whose SiO₂

column chromatography with hexane/CH₂Cl₂(9:1) afforded 20 as

a colorless oil (6.6 mg, 29%): MS (GC, EI): m/z = 302 [M⁺], 283

2-Methoxy-4Ј-(pentafluorosulfanyl)biphenyl, 3-Methoxy-4Ј-(penta-

fluorosulfanyl)biphenyl, and 4-Methoxy-4Ј-(pentafluorosulfanyl)bi-

phenyl (19e) (Isomer Mixture): NaI (22.0 mg, 0.147 mmol) was

added portion-wise to a solution of 1 (31.0 mg, 0.0974 mmol) and

anisole (96.0 mg, 0.888 mmol) in CH₃CN (53.5 mg). The reaction

mixture was neutralized with Na₂CO₃and filtered through Celite

545 using hexane. The solvent was evaporated to give a pale yellow

oil, Silica column chromatography with hexane afforded 16b

(15.3 mg, 48 %), 2-methoxy-4Ј-(pentafluorosulfanyl)biphenyl as

colorless crystals (4.0 mg, 13%), 3-methoxy-4Ј-(pentafluorosulf-

anyl)biphenyl as a colorless oil (0.2 mg, 1%), a fraction containing

both 3-methoxy-4Ј-(pentafluorosulfanyl)biphenyl and 4-methoxy-

4Ј-(pentafluorosulfanyl)biphenyl (1:1) as colorless oil (2.0 mg, 7%),

and 4-methoxy-4Ј-(pentafluorosulfanyl)biphenyl as colorless crys-

tals (0.7 mg, 2%).

[M⁺– F]. IR (ATR): ν = 2951, 1593, 1504, 1288, 1248, 1163, 1103,

˜

1

837 cm^–1. H NMR (500 MHz, CDCl₃): δ = 7.74 (d, J = 9.2 Hz, 2

H), 6.98 (t, J = 9.2 Hz, 2 H), 4.40 (q, J = 7.9 Hz, 2 H) ppm. ¹³C

NMR (125 MHz, CDCl₃): δ = 158.8 (C), 148.1 (C), 128.0 (2CH),

122.9 (q, J = 278 Hz, CF₃), 114.5 (2CH), 65.7 (q, J = 36 Hz,

CH₂) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 85.0 (quint, J =

150 Hz, 1 F), 64.0 (d, J = 150 Hz, 4 F) ppm.

1-Fluoro-4-(pentafluorosulfanyl)benzene (21): MS (GC, EI): m/z =

222 [M⁺], 203 [M⁺– F]. ¹H NMR (500 MHz, CDCl₃): δ = 7.77

(dd, J = 8.8, 4.7 Hz, 2 H), 7.47 (t, J = 8.8 Hz, 2 H) ppm. ¹⁹F NMR

(470 MHz, CDCl₃): δ = 84.1 (quint, J = 150 Hz, 1 F), 62.6 (d, J =

150 Hz, 4 F), –107.1 (s, 1 F) ppm.

2-Methoxy-4Ј-(pentafluorosulfanyl)biphenyl (ortho): Colorless crys-

tals; m.p. 80.5–81.5 °C. IR (ATR): ν = 2944, 2841, 1601, 1485,

˜

1400, 1264, 1244, 831 cm^–1. MS (GC, EI): m/z = 310 [M⁺], 291

1

[M⁺– F], 204, 168, 139. H NMR (500 MHz, CDCl₃): δ = 7.78 (d,

J = 8.8 Hz, 2 H), 7.61 (d, J = 8.8 Hz, 2 H), 7.38 (td, J = 7.8, 1.7 Hz,

1 H), 7.30 (dd, J = 7.5, 1.7 Hz, 1 H), 7.06 (td, J = 8.5, 1.0 Hz, 1

H) 7.01 (d, J = 8.3 Hz), 3.83 (s, 3 H) ppm. ¹³C NMR (125 MHz,

CDCl₃): δ = 156.3 (C), 152.4 (C), 142.0 (C), 130.7 (C), 129.7 (3CH),

128.4 (CH), 125.6 (2CH), 121.0 (CH), 111.3 (CH), 55.5 (CH₃) ppm.

¹⁹F NMR (470 MHz, CDCl₃): δ = 85.0 (quint, J = 150 Hz, 1 F),

63.1 (d, J = 150 Hz, 4 F) ppm.

iii) In Triflic Acid: Diazonium salt 1 (7.1 mg, 0.022 mmol) was dis-

solved in TfOH (0.27 g) and the mixture was heated at 50 °C for 1

month. After cooling, a portion of the mixture was diluted with

CDCl₃and analyzed by NMR showing the formation of 4-(fluoro-

sulfonyl)phenyl trifluoromethanesulfonate 22. The mixture was di-

luted with CH₂Cl₂, washed with 10% Na₂CO₃aq. and dried with

MgSO₄. Most of the solvent was evaporated to give a pale yellow

oil, which was purified by SiO₂column chromatography with hex-

ane/CH₂Cl₂(7:3) to afforded 22 as a colorless oil (6.9 mg, 100%).

3-Methoxy-4Ј-(pentafluorosulfanyl)biphenyl (meta): Colorless oil.

IR (ATR): ν = 2916, 2849, 1740, 1599, 1572, 1487, 1463, 1397,

˜

1224, 1102, 1030, 833 cm^–1. MS (GC, EI): m/z = 310 [M⁺], 202,

MS (GC, EI): m/z = 308 [M⁺], 289 [M⁺– F]. IR (ATR): ν = 3107,

˜

1

172, 159, 154, 139. H NMR (500 MHz, CDCl₃): δ = 7.82 (d, J = 1587, 1486, 1418, 1213, 1136, 881 cm^–1

.

¹H NMR (500 MHz,

8.8 Hz, 2 H), 7.65 (d, J = 8.8 Hz, 2 H), 7.40 (t, J = 8.0 Hz, 1 H),

7.17 (d, J = 8.0 Hz, 1 H), 7.10 (t, J = 2.0 Hz, 1 H), 6.96 (dd, J =

CDCl₃): δ = 8.16 (d, J = 9.0 Hz, 2 H), 7.57 (d, J = 9.0 Hz, 2

H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 153.9 (C), 133.2 (C),

1642

www.eurjoc.org

Eur. J. Org. Chem. 2014, 1630–1644

Synthesis of Aromatic SF₅Compounds

131.2 (2CH), 123.0 (2CH). ¹⁹F NMR (470 MHz, CDCl₃): δ = 66.6

(s, 1 F), –72.5 (s, 3 F) ppm.

(d, J = 8.9 Hz, 2 H), 5.29 (m, 1 H), 4.99 (m, 1 H) ppm. ¹³C NMR

(125 MHz, CDCl₃): δ = 161.5 (C), 131.0 (2CH), 130.6 (C), 120.6

(q, J = 283 Hz, C), 119.7 (q, J = 280 Hz, C) 117.4 (2CH), 74.9 (m,

C), 72.0 (m, C) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = –73.1 (d,

J = 6 Hz, 6 F), –73.2 (d, J = 6 Hz, 6 F) ppm.

iv) In 1,1,1,3,3,3-hexafluoro-2-propanol HFIP: Diazonium salt 1

(106.8 mg, 0.3359 mmol) was dissolved in HFIP (7.16 g) and the

mixture was heated at 60 °C for 4 h. After cooling, Na₂CO₃was

added and the mixture was filtered. Most of the solvent was evapo-

rated to give a pale-yellow oil, which was purified by SiO₂column

chromatography with hexane/CH₂Cl₂(9:1) to afford 1-(pentafluoro-

sulfanyl)-4-[2,2,2-trifluoro-1-(trifluoromethyl)ethoxy]benzene (col-

orless oil; 2.0 mg, 1.6%), 1-fluoro-4-(fluorosulfonyl)benzene^[23]

(colorless oil; 7.7 mg, 13%), and 2,2,2-trifluoro-1-(trifluoromethyl)-

ethyl 4-fluorophenylsulfonate^[28](colorless oil; 15.7 mg, 14.3%).

v) In CF₃COOH (TFAH): Diazonium salt

1

(29.7 mg,

0.0934 mmol) was dissolved in TFAH (0.96 g) and the mixture was

heated with 70 °C for 12 h. After cooling, a portion of the mixture

was diluted with CDCl₃and analyzed by NMR which indicated

the formation of 1-fluoro-4-(pentafluorosulfanyl)benzene,^[7]1-

fluoro-4-(fluorosulfonyl)benzene,^[23]4-(pentafluorosulfanyl)phen-

ol,^[9a]and 4-(fluorosulfonyl)phenol.^[24,25]Most of the solvent was

Elution with hexane/CH₂Cl₂(8:2) gave 1-(fluorosulfonyl)-4-[2,2,2- evaporated to give a pale yellow oil, which was purified by SiO₂

trifluoro-1-(trifluoromethyl)ethoxy]benzene (colorless oil, 6.6 mg,

6.0%), a 2:1 mixture of 1-(fluorosulfonyl)-4-[2,2,2-trifluoro-1-(tri-

fluoromethyl)ethoxy]benzene and 2,2,2-trifluoro-1-(trifluoro-

column chromatography with hexane/EtOAc (9:1) to afford: 4-

(pentafluorosulfanyl)phenol, 4-(fluorosulfonyl)phenol (colorless

oil; 3.5 mg), and 4-(fluorosulfonyl)phenol (colorless oil; 2.4 mg,

methyl)ethyl-4-[2,2,2-trifluoro-1-(trifluoromethyl)ethoxy]phenyl- 15%).

sulfonate (colorless oil, 27.2 mg, 19.1%), and 4-[2,2,2-trifluoro-1-

4-(Fluorosulfonyl)phenol: Colorless oil. MS (GC, EI): m/z = 176

(trifluoromethyl)ethoxy]phenylsulfonate (colorless oil, 3.8 mg,

2.4%).

1

[M⁺], 157 [M⁺– F], 109, 81, 65, 63. H NMR (500 MHz, CDCl₃):

δ = 7.91 (d, J = 8.8 Hz, 2 H), 7.02 (d, J = 8.8 Hz, 2 H), 2.89 (br.

s, 1 H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 161.9 (C), 131.2

(2CH), 131.1 (C), 116.4 (2CH) ppm. ¹⁹F NMR (470 MHz, CDCl₃):

δ = 67.2 (s, 1 F) ppm.

1-(Pentafluorothio)-4-[2,2,2-trifluoro-1-(trifluoromethyl)ethoxy]-

benzene: Colorless oil. MS (GC, EI): m/z = 370 [M⁺], 361 [M⁺

–

F], 262, 224, 111, 83. IR (ATR): ν = 1596, 1502, 1369, 1291, 1244,

˜

1

1199, 1105, 846 cm^–1. H NMR (500 MHz, CDCl₃): δ = 7.79 (d, J

vi) In [BMIM][NTf₂]: Diazaonium salt 1 (44.8 mg, 0.141 mmol) was

dissolved in [BMIM][NTf₂] (0.4514 g, 1.076 mmol) and the mixture

was heated at 70 °C for 15 h. NMR analysis of the reaction mixture

indicated the formation of 25 and 26 and 21 in a 77:8:15 ratio. The

mixture was extracted with hexane and the solvent was evaporated

to give a pale yellow oil, whose SiO₂column chromatography with

hexane/CH₂Cl₂(8:2) afforded 26 (colorless crystals; 2.0 mg, 3%)

and 25 (colorless oil; 24.3 mg, 36%).

= 9.1 Hz, 2 H), 7.14 (d, J = 9.1 Hz, 2 H) ppm. ¹³C NMR

(125 MHz, CDCl₃): δ = 158.6 (C), 149.7 (C), 128.3 (2CH), 120.2

(q, J = 285 Hz, 2 C), 116.6 (2CH), 75.4 (m, CH) ppm. ¹⁹F NMR

(470 MHz, CDCl₃): δ = 84.0 (quint, J = 151 Hz, 1 F), 63.6 (d, J =

151 Hz, 4 F), –73.4 (d, J = 5 Hz, 6 F) ppm.

1-Fluoro-4-(fluorosulfonyl)benzene: Colorless oil. IR (ATR): ν =

˜

1593, 1498, 1416, 1210, 836, 768 cm^–1. MS (GC, EI): m/z = 178

[M⁺], 159 [M⁺– F], 111, 83, 75. ¹H NMR (500 MHz, CDCl₃): δ =

8.07 (dd, J = 9.1, 4.9 Hz, 2 H), 7.33 (t, J = 8.4 Hz, 2 H) ppm. ¹³C

NMR (125 MHz, CDCl₃): δ = 166.8 (d, J = 260 Hz, C), 131.5 (d,

J = 10 Hz, 2CH), 129.0 (d, J = 26 Hz, C), 117.2 (d, J = 23 Hz,

2CH) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 66.8 (s, 1 F), –99.3

(m, 1 F) ppm.

25: MS (GC, EI): m/z = 483 [M⁺], 464 [M⁺– F]. IR (ATR): ν =

˜

1495, 1395, 1343, 1219, 1130, 1076, 839 cm^–1. ¹H NMR (500 MHz,

CDCl₃): δ = 7.95 (d, J = 9.1 Hz, 2 H), 7.48 (t, J = 9.1 Hz, 2

H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 153.9 (C), 149.6 (C),

129.0 (2CH), 122.4 (2CH), 118.7 (q, J = 221 Hz, CF₃), 118.6 (q, J

= 221 Hz, CF₃) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 81.6

(quint, J = 150 Hz, 1 F), 63.1 (d, J = 150 Hz, 4 F), –72.5 (s, 3 F),

–77.8 (s, 3 F) ppm.

2,2,2-Trifluoro-1-(trifluoromethyl)ethyl 4-Fluorophenylsulfonate:

Colorless oil. IR (ATR): ν = 1593, 1498, 1375, 1363, 1290, 1234,

˜

1204, 1191, 1066, 880, 837, 793 cm^–1. MS (GC, EI): m/z = 326

26: Dec. 245.0 °C (in a sealed tube). MS (GC, EI): m/z = 483 [M⁺],

1

[M⁺], 159, 111, 75. H NMR (500 MHz, CDCl₃): δ = 7.98 (dd, J

464 [M⁺– F]. IR (ATR): ν = 1449, 1232, 1219, 1117, 837 cm^–1. ¹H

˜

= 8.9, 4.9 Hz, 2 H), 7.30 (dd, J = 8.9, 8.0 Hz, 2 H), 5.28 (m, 1

H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 166.6 (d, J = 260 Hz,

C), 131.2 (d, J = 10 Hz, 2CH), 130.4 (d, J = 3 Hz, C), 119.7 (q, J

= 284 Hz, 2 C), 117.1 (d, J = 23 Hz, 2CH), 72.0 (m, C) ppm. ¹⁹F

NMR (470 MHz, CDCl₃): δ = 73.1 (d, J = 6 Hz, 1 F), –100 (m, 1

F) ppm.

NMR (500 MHz, CDCl₃): δ = 7.92 (d, J = 8.7 Hz, 2 H), 7.54 (t, J

= 8.7 Hz, 2 H) ppm. ¹³C NMR (125 MHz, CDCl₃): δ = 154.7 (C),

134.4 (C), 131.6 (2CH), 127.9 (2CH), 121.7 (q, J = 222 Hz,

CF₃) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 81.3 (quint, J =

150 Hz, 1 F), 62.7 (d, J = 150 Hz, 4 F), –70.4 (s, 6 F) ppm.

vii) In [BMIM][BF₄] and [BMIM][PF₆]: Diazonium salt 1 (10.1 mg,

0.0318 mmol) was dissolved in the IL (90 mg) and the mixture was

heated to 70 °C in an oil bath for 8 h. NMR analysis of the reaction

mixture indicated quantitative formation of fluoro derivative

21.^[7,23]

1-(Fluorosulfonyl)-4-[2,2,2-trifluoro-1-(trifluoromethyl)ethoxy]-

benzene: Colorless oil. IR (ATR): ν = 1596, 1498, 1290, 1248, 1211,

˜

1200, 1180, 1103, 900, 776 cm^–1. MS (GC, EI): m/z = 326 [M⁺],

1

307 [M⁺– F], 259, 224, 92. H NMR (500 MHz, CDCl₃): δ = 8.07

(d, J = 8.9 Hz, 2 H), 7.29 (d, J = 8.9 Hz, 2 H), 5.00 (m, 1 H) ppm.

¹³C NMR (125 MHz, CDCl₃): δ = 161.8 (C), 131.3 (2CH), 128.6 Computational Methods: Structures were optimized using a C₁mo-

(d, J = 29 Hz, C), 120.5 (q, J = 279 Hz, 2 C), 117.4 (2CH), 74.8

lecular point group by the density function theory (DFT)

(m, C) ppm. ¹⁹F NMR (470 MHz, CDCl₃): δ = 66.8 (s, 1 F), –73.2 method^[29]at B3LYP/6-31G(d) level and B3LYP/6-311+G(d,p)

(d, J = 6 Hz, 6 F) ppm.

using the Gaussian 03 package.^[30]All computed geometries were

verified by frequency calculations to have no imaginary frequencies.

The solvent effect was estimated by the polarized continuum model

(PCM).^[31–33]Energies are summarized in Tables S1 and S2.

2,2,2-Trifluoro-1-(trifluoromethyl)ethyl-4-[2,2,2-trifluoro-1-(tri-

fluoromethyl)ethoxy]phenylsulfonate: Colorless oil. IR (ATR): ν =

˜

1589, 1496, 1375, 1291, 1240, 1198, 1175, 1104, 1065, 881,

798 cm^–1. MS (GC, EI): m/z = 474 [M⁺], 326, 307, 259, 243, 111.

¹H NMR (500 MHz, CDCl₃): δ = 7.99 (d, J = 8.9 Hz, 2 H), 7.27

CCDC-965267 (for 26), -965268 (for 2e), -965269 (for 14), and

-965270 (for 16c) contain the supplementary crystallographic data

Eur. J. Org. Chem. 2014, 1630–1644

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1643

T. Okazaki, K. K. Laali, S. D. Bunge, S. K. Adas

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Published Online: January 8, 2014

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Article Doi

4-(Pentafluorosulfanyl)benzenediazonium Tetrafluoroborate: A Versatile Launch Pad for the Synthesis of Aromatic SF5 Compounds via Cross Coupling, Azo Coupling, Homocoupling, Dediazoniation, and Click Chemistry

DOI: 10.1002/ejoc.201301538

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