An efficient stereoselective preparation of cis-perfluoroalkenylzinc reagents [(E)-RFCF{double bond, long}CFZnCl] by the metallation of 1H,1H-perfluoroalkanes and their derivatization to cis-1-arylperfluoroalkenes [(Z)-RFCF{double bond, long}CFAr]

Journal of Fluorine Chemistry 127 (2006) 456–470

www.elsevier.com/locate/ﬂuor

An efﬁcient stereoselective preparation of cis-perﬂuoroalkenylzinc

reagents [(E)-R_FCF CFZnCl] by the metallation of 1H,

1H-perﬂuoroalkanes and their derivatization

to cis-1-arylperﬂuoroalkenes [(Z)-R_FCF CFAr]

*

Anilkumar Raghavanpillai, Donald J. Burton

Department of Chemistry, The University of Iowa, Iowa City, IA 52242, United States

Received 22 December 2005; accepted 28 December 2005

Available online 21 February 2006

Abstract

Various 1H,1H-perﬂuoroalkanes (R_FCF₂CH₂F, R_F= CF₃, C₂F₅, C₄F₉, C₅F₁₁, C₆F₁₃, C₁₀F₂₁) were metallated using LDA in a THF solution of

ZnCl₂at RTor À78 8C to produce the corresponding perﬂuoroalkenylzinc reagents (R_FCF CFZnCl) in a cis-selective fashion. An increased yield

(75–83%) and cis-selectivity (>89%) of the perﬂuoroalkenylzinc reagents were observed for metallation reactions performed at À78 8C. The cis

selectivity was excellent for 1H,1H-perﬂuoroalkanes with larger R_Fgroups (C₄F₉, C₅F₁₁, C₆F₁₃, >96%). The cis-perﬂuoroalkenylzinc [(E)-

R_FCF CFZnCl] reagents were coupled with aryl iodides to obtain cis-1-arylperﬂuoroalkenes [(Z)-R_FCF CFAr] in 71–95% isolated yields. The

cis-perﬂuoroalkenylzinc reagents upon iodinolysis produced cis-1-iodoperﬂuoroalkenes [(E)-R_FCF CFI] in 68–70% isolated yield.

Keywords: 1H,1H-Perﬂuoroalkanes; 1-Arylperﬂuoroalkenes; Perﬂuoroalkenylzinc; 1-Iodoperﬂuoroalkenes; LHMDS; Dehydroﬂuorination; Pd(0) coupling

1. Introduction

ﬂuoroacetate [14] or diethyl-2-oxo-3-ﬂuorobutan-1,4-dioate

[15], desulfenylation of a-ﬂuorosulfoxide [16–18], domino

reaction based on an a normal Michael reaction [19], reduction

of diﬂuorooleﬁns [20,21], and ﬂuorinated organometallics [22–

29].

Fluorinated alkenes are versatile synthetic building blocks

because of their wide range of applications in the area of

ﬂuoropolymers, liquid crystalline materials and biologically

active agents [1–3]. The physical and biological properties of

alkenes largely depend on their conﬁguration, and thus

synthesis of polyﬂuorinated alkenes via an E or Z selective

route would allow studies on the stereochemical, synthetic,

kinetic, and biological aspects of ﬂuorinated alkenes. But

practical methods for the stereoselective synthesis of ﬂuori-

nated alkenes remain as an important synthetic challenge.

Various methodologies have been attempted for the stereo-

selective synthesis of different types of substituted ﬂuorinated

alkenes such as Horner–Wadsworth–Emmons reaction [4,5],

addition–elimination of polyﬂuoroethenes [6,7], dehydrohalo-

genation [8], chloroﬂuorocarbene chemistry [9,10], radical

reactions [11–13], chemistry involving ethyl phenylsulﬁnyl-

Recent investigations of Coe and co-workers realized the

potential of hydroﬂuorocarbons HFC-134a and HFC-133a as a

source for triﬂuorovinyllithium and chlorodiﬂuorovinyllithium

[30,31]. Based on this invention, we have developed excellent

room temperature preparative methods for a,b,b-triﬂuorostyr-

enes and a-halo-b,b-diﬂuorostyrenes [32–37] via correspond-

ing ﬂuorovinylzinc reagents. In our methodology, the

ﬂuorovinylzinc reagents were generated at room temperature

by an in situ metallation/transmetallation sequence followed by

a Pd(0) catalyzed coupling reaction of the zinc reagents with

aryl iodides to produce corresponding ﬂuorostyrenes (Scheme

1) [32–37]. The metallation of hydroﬂuorocarbons at tempera-

tures near room temperature was challenging as the inter-

mediate ﬂuorovinyllithiums are highly unstable (readily

eliminate LiF) at a temperature typically above À78 8C. But

by the systematic standardization of the reaction conditions and

by performing the metallation in situ, the ﬂuoroalkenylzinc

* Corresponding author. Tel.: +1 319 335 1363; fax: +1 319 335 1270.

E-mail address: donald-burton@uiowa.edu (D.J. Burton).

doi:10.1016/j.jﬂuchem.2005.12.022

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

457

Scheme 1. Synthesis of a,b,b-triﬂuorostyrenes and a-halo-b,b-diﬂuorostyrenes by metallation/coupling process.

reagents were generated in good yield via the corresponding

lithium reagents at room temperature.

similar dehydroﬂuorination method for the synthesis of (E)-1-

phenyl-1,2,3,3,3-pentaﬂuoropropene and (E)-1-aryl-1,2,2,3

,3,4,4,4-octaﬂuorobutene by the dehydroﬂuorination of the

corresponding precursor using lithium hexamethyldisilazide

base [56,57]. Excellent E-selectivity was observed during this

dehydroﬂuorination process (Scheme 2).

The success of this metallation methodology prompted us to

test this strategy for a stereoselective synthesis of perﬂuoroalk-

enylzinc reagents and 1-arylperﬂuoroalkenes from the corre-

sponding 1H,1H-perﬂuoroalkane (R_FCF₂CH₂F) precursors. 1-

Arylperﬂuoroalkenes are not very well documented compounds

and there are only a few methods available for their synthesis,

especially in a stereoselective fashion. One of the early methods

was developed by Dixon where reaction of phenyl lithium with

perhaloalkenes produced 1-phenylsubstituted alkenes in 20–

60% yields together with products formed by successive

displacement of ﬂuorines by phenyl groups [38]. Reaction of

various substituted aryl Grignard reagents and hexaﬂuoropro-

pene were also reported in 40–50% yield for aryl-1,2,3,3,3-

pentaﬂuoropropenes [39,40]. An improvement of the above

reaction was reported by Dmowski, where an etheral solution of

Grignard reagent was reacted with hexaﬂuoropropene in a

sealed tube [41]. Moreau et al. synthesized various 1-

substituted perﬂuoroalkenes from the reaction of perﬂuoroalk-

ene (RFCF CF₂, R_F= C₆F₁₃, C₄F₉) with Grignard reagents

[42,43]. All the above procedures produced the 1-arylper-

ﬂuoroalkene as a mixture of E and Z isomers, favoring the E

isomer (E/Z ꢀ80:20). Dmowski [44–50] and Wakselman and

co-workers [51] independently demonstrated that the geometry

of the oleﬁns affected the regiochemistry of the nucleophilic

reaction of polyﬂuorinated propenes. Thus, the stereoselective

synthesis of these alkenes was challenging and the ﬁrst

stereoselective preparation of (E)- and (Z)-1-phenylpentaﬂuor-

opropenes were reported from our laboratory, where cis- and

trans-1-iodopentaﬂuoropropenes were transformed to the

corresponding (E)- and (Z)-1-phenylpentaﬂuoropropenes via

zinc insertion followed by Pd(0) catalyzed coupling [52–54].

Kuroboshi and Hiyama et al. synthesized various (E)-1-aryl-

perﬂuoropropenes by dehydrohalogenation of the correspond-

ing precursor using DBU [55]. Excellent E selectivity was

observed in this dehydrohalogenation. They have also obtained

the Z-isomer of the above alkenes by a photochemical

isomerization reaction. We have very recently developed a

Thus the synthesis of (E)-R_FCF CFAr in good selectivity

was possible either by the organometallic or dehydrohalogena-

tion methods discussed above whereas the corresponding Z-

isomer was difﬁcult to obtain by any of these methods. The

preparation of 1-arylperﬂuoroalkenes via the corresponding

zinc reagent followed by Pd(0) coupling utilized pure cis- or

trans-1-iodo-perﬂuoroalkene (R_FCF CFI). The precursor for

the trans-iodide, [(Z)-R_FCF CHF] could be obtained via the

stereospeciﬁc phosphodeﬂuoridation of the readily available

perﬂuoro-1-alkene (R_FCF CF₂) [58–61]. The corresponding

precursors for the cis-iodide, [(E)-R_FCF CHF] are less

conveniently available than the trans-isomers. They have been

synthesized by the isomerization of (Z)-R_FCF CHF (R_F= CF₃,

C₂F₅–) using SbF₅[58,62], but this methodology was not

feasible for perﬂuoroalkenes with longer chains due to the

formation of internal isomers in addition to the desired product

[63]. So the synthesis of (Z)-1-arylperﬂuoroalkenes is rather

difﬁcult and it is useful to develop a methodology that would

generate them exclusively in good yield.

2. Results and discussion

Recently, Frohn et al. reported metallation of

C₆F₁₃CF₂CH₂F with 2 equiv. BuLi under conditions similar

to that of the metallation of HFC-134a [30,31] at low

temperature to produce the corresponding perﬂuoroalkenyl-

lithium (C₆F₁₃CF CFLi) in a cis-selective fashion (Scheme 3)

[64,65]. Here the initially formed intermediate lithium species

[C₆F₁₃CF₂CHFLi] eliminates LiF and leads to the (Z)-

C₆F₁₃CF CHF with 95% selectivity, which was then readily

consumed by the base to produce the perﬂuoroalkenyllithium

species. The perﬂuoroalkenyllithium species thus generated

was then successfully transformed to potassium cis-perﬂuor-

oocten-1-yltriﬂuoroborate (K[C₆F₁₃CF CFBF₃]) by treatment

with B(OCH₃)₃followed by K[HF₂] and aqueous HF.

The excellent cis-selectivity described in this elimination

prompted us to investigate a similar process to produce the

corresponding cis-perﬂuoroalkenylzinc reagents [(E)-R_FCF C

FZnCl] via our in situ metallation strategy. The cis-

perﬂuoroalkenylzinc reagents thus generated could be effec-

tively used in a coupling reaction with aryl iodides to produce

cis-1-arylperﬂuoroalkyloleﬁns [(Z)-R_FCF CFAr], and thus

Scheme 2. Synthesis of 1-arylperﬂuoroalkenes by dehydroﬂuorination of

suitable precursors.

458

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

Scheme 3. Preparation of cis-perﬂuoroocten-1-yltriﬂuoroborate via corresponding cis-perﬂuoroalkenyl lithium.

serve as a general methodology for the preparation of these

oleﬁns in a stereoselective fashion.

performed using lithium tetramethyl-4-methoxy piperidine (4-

methoxy LiTMP) at À78 8C, but no improvement in the

selectivity was observed (E/Z 89:11). Formation of the

perﬂuoropropenylzinc reagent was established by a hydrolysis

experiment where the zinc reagent obtained by the metallation

reaction was treated with acetic acid to obtain the correspond-

ing (Z)- and (E)-CF₃CF CFH with the retention of selectivity

of the zinc reagent (Z/E 87:13). A metallation reaction using

1 equiv. of LDA at À80 8C was also attempted but produced

only a 34% yield of the perﬂuoroalkenylzinc reagent along with

unreacted alkane CF₃CF₂CH₂F. No intermediate alkene

(CF₃CF CHF) was detected in this reaction mixture conﬁrm-

ing that the proton in CF₃CF CHF is more acidic than that of

the precursor alkane (CF₃CF₂CH₂F) which was readily

consumed by the base as soon as it was formed.

2.1. Synthesis of cis-perﬂuoroprop-1-enylzinc reagent [(E)-

CF₃CF CFZnCl] and (Z)-1-arylperﬂuoroprop-1-enes [(Z)-

CF₃CF CFAr]

Firstly, commercially available 1H,1H-perﬂuoropropane

(CF₃CF₂CH₂F) was chosen and its metallation was performed

with 2 equiv. of LDA in the presence of ZnCl₂at 15 8C [32,33]

to produce the corresponding perﬂuoropropenylzinc reagent

(CF₃CF CFZnCl) in 67% yield. ¹⁹F NMR analysis of the

reaction mixture showed that perﬂuoropropenylzinc reagent

was formed as a mixture of isomers with 82:18 selectivity in

favor of the cis-isomer. The Pd(0) catalyzed coupling reaction

of this zinc reagent with 4-ﬂuoroiodobenzene produced 1-(4-

ﬂuorophenyl)perﬂuoroprop-1-ene in 78% isolated yield with

similar stereoselectivity (Z/E 81:19) observed for the zinc

reagent. In order to improve the yield and cis-selectivity we

have carried out the metallation reaction at À78 8C. ¹⁹F NMR

analysis of the reaction mixture revealed an improved yield

(81%) and cis-selectivity ((E/Z)-CF₃CF CFZnCl = ꢀ89:11) of

the zinc reagent. The ratio of the mono and bis zinc reagents in

the THF medium was not clear, but addition of 1 equiv. of

TMEDA to the reaction medium clearly showed distinct peaks

for the mono and bis zinc reagents complexed to TMEDA

(mono/bis = ꢀ70:30). We then attempted the metallation

reaction using a more sterically hindered base in order to

push the selectivity further. Thus, the metallation reaction was

After obtaining the perﬂuoroalkenylzinc reagent in good

yield and cis-selectivity we have performed the Pd(0) catalyzed

coupling reaction of the zinc reagent mixture with various aryl

iodides. The reaction proceeded well with aryl iodides having

both electron donating and withdrawing groups in the aromatic

ring to produce the corresponding 1-arylperﬂuoroopropenes in

excellent isolated yield. The conﬁguration of the zinc reagent

was retained during the coupling process to produce the cis-1-

arylperﬂuoropropenes as the major isomer. The result of

coupling reaction of the cis-perﬂuoroprop-1-enylzinc reagent

(prepared at À78 8C) with aryl iodides is summarized in

Table 1. The Z and E isomers were very close in their R_Fvalues

and were isolated as mixtures by column chromatography using

hexanes as eluent.

Table 1

Pd(0) catalyzed coupling reaction of perﬂuoropropenylzinc reagent (prepared at À78 8C) with aryl iodides: synthesis of (Z)-1-arylperﬂuoroprop-1-enes

Entry

Ar

Time (h)

Yield (%) of

Z/E ratio^a

ArCF CFCF₃

1

2

3

4

5

C₆H₅–

8

80

77

87

78

82

87:13

89:11

90:10

88:12

4-FC₆H₄

2-CH₃C₆H₄–

3-CH₃OC₆H₄–

3-CF₃C₆H₄–

10

6

8

a

3

The Z/E ratio determined by ¹⁹F NMR (³J_FF(trans)= ꢀ131 Hz, J_FF(cis)= ꢀ12 Hz).

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

459

Table 2

during the coupling process and no isomerization was observed.

For a sterically hindered ortho substituent, 2-isopropyl, the

coupling reaction was sluggish (entry 3), and after 18 h at

65 8C, furnished 71% isolated yield of the coupled product.

Pd(0) catalyzed coupling reaction of the perﬂuorobutenylzinc reagent (prepared

at À78 8C) with aryl iodides: synthesis of (Z)-1-arylperﬂuorobut-1-enes

2.3. Synthesis of 1H,1H-perﬂuoroalkanes

The improvement in the cis-stereoselectivity during the

metallation of C₂F₅CF₂CH₂F in comparison to CF₃CF₂CH₂F

indicates that there is some inﬂuence by the larger perﬂuor-

oethyl group during the course of the key elimination process

(see Section 2.7). This prompted us to consider 1H,1H-

perﬂuoroalkanes with even larger R_Fgroups, such as C₄F₉,

C₅F₁₁, C₆F₁₃, C₁₀F₂₁for this metallation process. So four

1H,1H-perﬂuoroalkanes (R_FCF₂CH₂F, R_F= C₄F₉, C₅F₁₁,

C₆F₁₃, C₁₀F₂₁) were prepared from the corresponding alcohol

(Scheme 4) [64]. The precursor alcohols (R_FCF₂CH₂OH) were

either commercially available or synthesized by the room

temperature reduction of the methyl ester of the corresponding

acids (R_FCF₂CO₂Me) using NaBH₄[66].

Entry

Ar

Time (h)

Yield (%) of

Z/E ratio^a

ArCF CFC₂F₅

1

2

3

4

C₆H₅–

6

5

89

81

71

83

93:7

94:6

93:7

4-FC₆H₄

2-(CH₃)₂CHC₆H₄–

3-CF₃C₆H₄–

18

8

a

The Z/E ratio determined by ¹⁹F NMR (³J_FF(trans)= ꢀ133 Hz,

³J_FF(cis)= ꢀ11 Hz).

2.2. Synthesis of cis-perﬂuorobut-1-enylzinc reagent

[(E)-C₂F₅CF CFZnCl] and (Z)-1-arylperﬂuorobut-1-enes

[(Z)-C₂F₅CF CFAr]

2.4. Synthesis of cis-perﬂuorohex-1-enylzinc reagent

[(E)-C₄F₉CF CFZnCl] and (Z)-1-arylperﬂuorohex-1-ene

[(Z)-C₄F₉CF CFAr]

After the successful preparation of (Z)-1-arylperﬂuoroprop-

1-enes from 1H,1H-perﬂuoropropane we have attempted a

similar sequence of experiments for the commercially available

higher homologue 1H,1H-perﬂuorobutane (C₂F₅CF₂CH₂F).

Metallation of C₂F₅CF₂CH₂F in the presence of ZnCl₂at 15 8C

in THF solvent produced the corresponding perﬂuorobut-1-

enylzinc reagent (C₂F₅CF CFZnCl) in 61% yield. ¹⁹F NMR

analysis revealed that a slightly improved selectivity (E/Z

86:14) was obtained in comparison to that of the perﬂuor-

opropenylzinc reagent preparation under similar conditions.

The metallation reaction was then performed at À78 8C in THF

medium in the presence of ZnCl₂and the ¹⁹F NMR revealed

that the perﬂuorobutenylzinc reagent was formed in 76% yield

with an improved selectivity towards the cis-isomer ((E/Z)-

C₂F₅CF CFZnCl = ꢀ94:6). Addition of 1 equiv. of TMEDA to

this zinc reagent mixture clearly showed distinguishable peaks

for the mono and bis zinc reagents (mono/bis = ꢀ65:35).

Palladium catalyzed cross-coupling of this zinc reagent with

various aryl iodides (having both electron donating and

withdrawing groups in the aromatic ring) was then attempted

and produced the 1-arylperﬂuorobutenes in excellent isolated

yield. The results of the coupling reaction of perﬂuorobute-

nylzinc reagent (prepared at À78 8C) with aryl iodides are

summarized in Table 2. The cis-conﬁguration remained intact

Metallation of C₄F₉CF₂CH₂F was performed using LDA in

the presence of ZnCl₂under the standard reaction conditions

(À78 8C in THF) to obtain the corresponding perﬂuorohex-1-

enylzinc reagent [C₄F₉CF CFZnCl] in 75% yield with

excellent cis-selectivity (E/Z 96:4). The ¹⁹F NMR spectrum

of the zinc reagent mixture was complex to determine the mono

and bis ratio, but addition of 1 equiv. of TMEDA made it

relatively simple indicating a 70:30 mixture of the mono and bis

zinc reagents. Palladium catalyzed cross-coupling reaction of

the zinc reagent with various aryl iodides was then performed

and the reaction yielded 1-arylperﬂuorohexenes in excellent

isolated yield (78–81%) and cis-selectivity (>95%). The results

of the coupling reaction of perﬂuorohex-1-enylzinc reagent

with various aryl iodides are summarized in Table 3.

2.5. Synthesis of cis-perﬂuorohept-1-enylzinc reagent

[(E)-C₅F₁₁CF CFZnCl] and (Z)-1-arylperﬂuorohept-1-

enes [(Z)-C₅F₁₁CF CFAr]

The metallation of C₅F₁₁CF₂CH₂F was then attempted both

at 0 and at À78 8C with 2 equiv. of LDA in presence of ZnCl₂.

At 0 8C, the reaction produced 75% of the perﬂuorohept-1-

Scheme 4. Synthesis of 1H,1H-perﬂuoroalkanes.

460

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

Table 3

Pd(0) catalyzed coupling reaction of the perﬂuorohex-1-enylzinc reagent with aryl iodides: synthesis of (Z)-1-arylperﬂuorohex-1-enes

Entry

Ar

Time (h)

Yield (%) of

Z/E ratio^a

ArCF CFC₄F₉

1

2

3

4

C₆H₅–

8

15

6

81

79

78

96:4

95:5

2-CH₃C₆H₄–

4-CH₃OC₆H₄–

3-CF₃C₆H₄–

8

a

3

The Z/E ratio determined by ¹⁹F NMR (³J_FF(trans)= ꢀ132 Hz, J_FF(cis)= ꢀ12 Hz).

enylzinc reagent [C₅F₁₁CF CFZnCl] with good cis-selectivity

(E/Z 88:12). Palladium catalyzed coupling reaction of the zinc

reagent with iodobenzene produced the 1-phenylperﬂuorohep-

tene with similar selectivity (Z/E 87:13). When the reaction was

performed at À78 8C, an 83% yield of the zinc reagent was

trans-perﬂuoroheptenylzinc reagent during this sluggish

coupling reaction.

2.6. Synthesis of cis-perﬂuorooct-1-enylzinc reagent

[(E)-C₆F₁₃CF FZnCl] and (Z)-1-arylperﬂuorooct-1-enes

[(Z)-C₆F₁₃CF CFAr]

formed with exclusive formation of the cis-isomer (E/Z, 99:1).

Pd(0) catalyzed coupling reaction of the perﬂuoroheptenylzinc

reagent (prepared at À78 8C) with various aryl halides was then

performed and the results are summarized in Table 4. The

coupling reaction was equally good for aryl iodides with both

electron donating or withdrawing groups in the aromatic ring to

afford a series of (Z)-1-arylperﬂuoroheptenes almost exclu-

sively as a single isomer. With 2-methyl-6-nitroiodobenzene,

the reaction was sluggish, but heating for 32 h produced the

coupled product in 31% isolated yield (Table 4, entry 3). The

ratio of the cis- and trans-1-(2-methyl-6-nitrophenyl)perﬂuor-

oheptene (91:9) formed in this reaction differed from that of the

starting perﬂuoroheptenylzinc reagent (99:1). This observation

indicates either isomerization or a preferred reactivity of the

Metallation of C₆F₁₃CF₂CH₂F was performed at À78 8C

with 2 equiv. of LDA in presence of ZnCl₂to obtain 79% yield

of the zinc reagent. The ¹⁹F NMR analysis revealed that the cis-

isomer was formed almost exclusively (E/Z, 98:2). It was

difﬁcult to assign peaks for the mono and bis zinc reagent

species even with the addition of TMEDA. Palladium catalyzed

coupling reaction of the cis-perﬂuorooct-1-enylzinc reagent

with various aryl iodides was then performed and we obtained

the corresponding cis-1-arylperﬂuorooctenes in very good

isolated yield. The results of the coupling reaction of

perﬂuorooct-1-enylzinc reagent with aryl iodides are summar-

ized in Table 5.

Table 4

Pd(0) catalyzed coupling reaction of the perﬂuoroheptenylzinc reagent (prepared at À78 8C) with aryl iodides: synthesis of (Z)-1-arylperﬂuorohept-1-enes

Entry

Ar

Time (h)

Yield (%) of

Z/E ratio^a

ArCF CFC₅F₁₁

1

C₆H₅–

8

12

32

8

89

91

31

92

86

99:1

91:9

98:2

2

3^b

4-FC₆H₄

2-CH₃(6-NO₂)C₆H₃–

4-CH₃OC₆H₄–

3-CF₃C₆H₄–

4

5

6

a

3

The Z/E ratio determined by ¹⁹F NMR (³J_FF(trans)= ꢀ132 Hz, J_FF(cis)= ꢀ11 Hz).

b

Product oleﬁn was contaminated with traces of 2-methyl-6-nitroiodobenzene.

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

461

Table 5

Pd(0) catalyzed coupling reaction of the perﬂuorooct-1-enylzinc reagent with aryl iodides: synthesis of (Z)-1-arylperﬂuorooct-1-enes

Entry

Ar

Time (h)

Yield (%) of

Z/E ratio^a

ArCF CFC₆F₁₃

1

2

3

4

5

C₆H₅–

6

15

18

8

81

91

78

87

95

98:2

97:3

98:2

4-FC₆H₄–

2-CH₃C₆H₄–

4-CH₃OC₆H₄–

3-CF₃C₆H₄–

10

a

3

The Z/E ratio determined by ¹⁹F NMR (³J_FF(trans)= ꢀ131 Hz, J_FF(cis)= ꢀ12 Hz).

2.7. Synthesis of cis-perﬂuorododec-1-enylzinc reagent

[(E)-C₁₀F₂₁CF CFZnCl] and (Z)-1-arylperﬂuorododec-1-

enes [(Z)-C₁₀F₂₁CF CFAr]

and anti-periplanar conformations of R_FCF₂CH₂F. On the basis

of spectral data and theoretical calculations it was established

that the syn-clinal conformations are favored over the anti-

periplanar conformations for 1,2-diﬂuoroethanes despite the

dipole or steric repulsion resulting from electronegative gauche

ﬂuorine atoms [67]. It was also established that the syn-clinal

effect is due to the relatively large electron ﬂow from the s_C–H

bond towards to the s_C^Ã_ÀFrelative to the electron ﬂow from s_C–F

bond to the s^Ã_CÀFbond in the anti-periplanar conformation [67].

Based on similar facts, 1H,1H-perﬂuoroalkanes adopts more

stable syn-clinal conformation (Fig. 1A) relative to the less

favorable anti-periplanar conﬁrmation (Fig. 1B) despite having

steric or repulsive interactions resulting from the electro-

negative gauche ﬂuorine atoms. The attack of the base on the

more favored syn-clinal conformation results in the lithiated

mono anion (R_FCF₂CHFLi), which internally eliminates LiF to

produce the cis-alkene as the preferred isomer during the

metallation process. Additionally, the anti-periplanar con-

ﬁrmation (B) is destabilized by the signiﬁcant steric as well as

electronic repulsive interaction between the gauche R_Fgroup

and F thus favoring A as the preferred conformation [68]. Thus

more bulky the R_Fgroup in the 1H,1H-perﬂuoroalkenes, the

higher the ratio of cis-isomer during the metallation process.

Metallation of a 1H,1H-perﬂuorododecane (C₁₀F₂₁CF₂

CH₂F) was also attempted in THF or a THF-diethyl ether

solution at À78 8C. But, unfortunately, the reaction did not

proceed well at À78 8C due to the poor solubility of

C₁₀F₂₁CF₂CH₂F in THF or THF-diethyl ether. The reaction

was then performed at 0 8C in the THF-diethyl ether medium and

produced the perﬂuorododec-1-enylzinc reagent in 61% yield

but with a slightly diminished selectivity towards the cis isomer

(E/Z ꢀ93:7). The palladium catalyzed cross-coupling reaction of

the perﬂuorododec-1-enylzinc reagent with various aryl iodides

was then performed and the reaction produced 1-arylperﬂuor-

ododecenes in good yield (72–81%) and cis-selectivity (>92%).

The results of the coupling reaction of perﬂuorododec-1-

enylzinc reagent with aryl iodides are summarized in Table 6.

2.8. Stereochemistry of the oleﬁnation

The excellent cis-selectivity observed during the metallation

of R_FCF₂CH₂F could be explained by looking at the syn-clinal

Table 6

Pd(0) catalyzed coupling reaction of the perﬂuorododec-1-enylzinc reagent with aryl iodides: synthesis of (Z)-1-arylperﬂuorododec-1-enes

Entry

Ar

Time (h)

Yield (%)^aof

Z/E ratio^b

ArCF CFC₁₀F₂₁

1

2

3

4

C₆H₅–

12

10

12

78

76

72

81

94:6

93:7

92:8

93:7

4-CH₃OC₆H₄–

4-F C₆H₄–

3-CF₃C₆H₄–

a

The product oleﬁn was contaminated with traces of C₁₀F₂₁CF₂CH₂F and Z-C₁₀F₂₁CF CHF.

3

b

The Z/E ratio determined by ¹⁹F NMR (³J_FF(trans)= ꢀ130 Hz, J_FF(cis)= ꢀ10 Hz).

462

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

Fig. 1. Syn-clinal and anti-periplanar conformations of R_FCF₂CH₂F. The more stable syn-clinal form (A) results in the cis-alkene during the metallation process.

2.9. Synthesis of cis-1-iodoperﬂuoroalkenes

under palladium catalysis to produce cis-1-arylperﬂuoroalk-

enes in excellent isolated yield. The cis-perﬂuoroalkenenylzinc

reagents were also subjected to iodinolysis to afford cis-1-

iodoperﬂuoroalkenes ((E)-R_FCF CFI) in excellent isolated

yield. Overall this methodology serves as the ﬁrst general route

for the synthesis of the relatively difﬁcult cis-1-arylperﬂuor-

oalkenes and cis-1-iodoperﬂuoroalkenes.

We also extended this methodology for a convenient

synthesis of cis-1-iodoperﬂuoroalkenes. Trans-1-iodo-perﬂuor-

oalkenes ((Z)-R_FCF CFI) are well known and are prepared

either by metallation of the (E)-R_FCF CFH, followed by

iodinolysis [69,70] or thermal decomposition of the perﬂuor-

oalkyl Grignard reagents [71,72]. However, the cis-1-iodo-

perﬂuoroalkenes ((E)-R_FCF CFI) are less conveniently avail-

able and more difﬁcult to synthesize, especially the higher

homologues [the higher homologues other than R_F= CF₃,

C₂F₅] cannot be prepared by the SbF₅catalyzed isomerization

of ((E)-R_FCF CFH) [58,62,63]. Iodinolysis of the cis-

perﬂuoroalkenylzinc reagent generated by our in situ metalla-

tion method could eventually give to the corresponding cis-1-

iodo-perﬂuoroalkenes. Thus, the perﬂuoroalkenylzinc reagents

generated by the metallation of 1H,1H-perﬂuoroheptene and

1H,1H-perﬂuorooctene at À78 8C were treated with iodine at

0 8C to produce the 1-iodoperﬂuoroheptene and 1-idodoper-

ﬂuorooctene in 68% and 70% isolated yields, respectively, with

>98% cis-selectivity (Scheme 5).

In conclusion, a stereoselective synthesis of cis-perﬂuor-

oalkenenylzinc reagents ([R_FCF CFZnCl], R_F= CF₃, C₂F₅,

C₄F₉, C₅F₁₁, C₆F₁₃, C₁₀F₂₁) was achieved by metallation of

1H,1H-perﬂuoroalkanes at low temperature. Temperature and

size of the R_Fgroup inﬂuenced the selectivity in the elimination

process. A cis-selectivity >96% was observed for 1H,1H-

perﬂuoroalkanes with larger R_Fgroups (C₄F₉, C₅F₁₁, C₆F₁₃)

when the metallation was performed at À78 8C. The cis-

perﬂuoroalkenenylzinc reagents coupled with aryl iodides

3. Experimental

¹H and ¹⁹F NMR spectra were recorded on a Brucker AC-

300 or a WM 360 or a DRX 400 Spectrometer. Chemical shifts

have been reported in ppm relative to an internal reference

(CDCl₃, CFCl₃or TMS). Unless noted otherwise, CDCl₃was

used as the NMR lock solvent. Yields of the perﬂuoroalk-

enylzinc reagent were calculated based on ZnCl₂. All the ¹⁹F

NMR yields were calculated based on PhCF₃as an internal

standard. All Z/E ratios of the perﬂuoroalkenylzinc reagents or

1-arylperﬂuoroalkenes were determined based on ¹⁹F NMR

coupling constants of the ﬂuorine attached to the double bond

3

(³J_FF(trans)= ꢀ130 Hz, J_FF(cis)= ꢀ11 Hz). Isolated yields of

the 1-arylperﬂuoroalkenes were based on aromatic iodide. Low

resolution mass spectra were obtained using a Voyeger GC/MS

instrument operated at 70 eVin the electron impact mode, using

a 15 m CB-5 column. The reported fragment peaks correspond

to the most abundant ions, in addition to the parent ion(s). High-

resolution mass spectra (HRMS) were obtained by the

University of Iowa High Resolution Mass Spectrometry

Facility. Column chromatography was carried out using silica

gel purchased from Em Science (Silica Gel 60, particle size

Scheme 5. Synthesis of cis-1-iodoperﬂuoroalkenes.

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

463

63–200 mm). All boiling points were measured during

distillation and are uncorrected. Tetrahydrofuran (THF),

diethylether and triglyme (TG) were dried by distillation from

sodium benzophenone/ketyl at atmospheric pressure immedi-

ately prior to use. Pd(PPh₃)₄was prepared by Coulson’s

procedure [73]. N₂was used without further puriﬁcation. All

other reagents and chemicals were obtained from commercial

sources and used directly.

3.1.3. 1H,1H-Perﬂuorooctane (C₇F₁₅CH₂F)

By a similar procedure 1H,1H-perﬂuorooctan-1-ol (15.2 g,

38.0 mmol) was treated with triethylamine (4.60 g, 45.6 mmol)

and perﬂuorobutanesulfonyl ﬂuoride (14.92 g, 49.4 mmol) to

obtain 1H,1H-perﬂuorooctylnonaﬂate as a white crystalline

solid (24.9 g, 36.5 mmol, 96%) [64] [mp: 42–44 8C]. ¹⁹F NMR

(CDCl₃): d À81.1 (t, J = 10 Hz, 3F), À81.2 (t, J = 10 Hz, 3F),

À110.2 (t, J = 12, 2F), À120.1 (m, 2F), À121.6 (m, 2F),

À122.3 (m, 4F), À123.3 (m, 4F), À126.3 (m, 2F), À126.6 (m,

1

3.1. Synthesis of 1H,1H-perﬂuoroalkanes

3.1.1. 1H,1H-Perﬂuorohexane (C₅F₁₁CH₂F)

2F). H NMR (CDCl₃): d 4.89 (t, J = 12 Hz, 2H).

1H,1H-Perﬂuorooctylnonaﬂate (23.3 g, 34.2 mmol) was

treated with KF (9.9 g, 170.8 mol) in TG (180.0 mL) at

200 8C for 5 h, followed by isolation as per the above procedure

to afford 1H,1H-perﬂuoroheptane as a colorless liquid (9.6 g,

23.9 mmol, 70%) [64] [bp: 131–133 8C]. ¹⁹F NMR (CDCl₃): d

À81.4 (t, J = 10 Hz, 3F), À122.6 (m, 4F), À123.3 (m, 4F),

À124.2 (m, 2F), À126.6 (m, 2F), À242.2 (tm, J = 46 Hz, 1F).

¹H NMR (CDCl₃): d 4.75 (dt, J = 46, 12 Hz, 2H).

A

solution of 1H,1H-perﬂuorohexan-1-ol (5.0 g,

16.7 mmol) and triethylamine (1.85 g, 18.3 mmol) in CH₂Cl₂

(10.0 mL) was cooled to 0 8C and perﬂuorobutanesulfonyl

ﬂuoride (6.04 g, 19.9 mmol) was added dropwise with stirring.

The reaction mixture was stirred at RT for 3 h and volatile

products and CH₂Cl₂removed under vacuum and the residue

dissolved in ether (40 mL) and washed many times with water

and dried over anhydrous Na₂SO₄. Removal of the solvent

produced pure 1H,1H-perﬂuorohexenylnonaﬂate as a viscous

liquid (8.91 g, 15.3 mmol, 92%) [¹⁹F NMR (CDCl₃): d À81.2

(t, J = 11 Hz, 3F), À81.3 (t, J = 11 Hz, 3F), À110.2 (t,

J = 15 Hz, 2F), À120.2 (m, 2F), À121.6 (m, 2F), À123.3

(m, 2F), À123.6 (m, 2F), À126.4 (m, 2F), À126.7 (m, 2F). ¹H

NMR (CDCl₃): d 4.88 (t, J = 12 Hz, 2H)].

The 1H,1H-perﬂuorohexylnonaﬂate (10.3 g, 17.7 mmol)

and KF (5.13 g, 88.5 mmol) were stirred in triglyme (TG)

(98.0 mL) at 180–200 8C for 3 h and the volatile products

distilled out during this period. The distillate was washed

with water (3Â 10 mL) and the organic layer dried over CaH₂

and distilled to obtain pure 1H,1H-perﬂuorohexane as a

colorless liquid (3.65 g, 12.0 mmol) in 68% yield [bp: 82–

83 8C]. ¹⁹F NMR (CDCl₃): d À81.3 (t, J = 11 Hz, 3F), À123.3

(m, 2F), À123.6 (m, 2F), À124.5 (m, 2F), À126.7 (m, 2F),

À242.2 (tm, J = 46 Hz, 1F). ¹H NMR (CDCl₃): 4.75 (dt,

J = 46, 12 Hz, 2H).

3.1.4. 1H,1H-Perﬂuoroctdodecane (C₁₁F₂₃CH₂F)

A suspension of 1H,1H-perﬂuorododecan-1-ol (19.0 g,

31.7 mmol) in CH₂Cl₂(50.0 mL), triethylamine (7.68 g,

76.0 mmol) and perﬂuorobutanesulfonyl ﬂuoride (12.43 g,

41.2 mmol) was stirred for 12 h. After ﬁltration and washing

of the residue with water, 1H,1H-perﬂuorooctylnonaﬂate was

obtained as a white crystalline solid (27.1 g, 30.7 mmol, 97%)

[mp: 94–95 8C]. ¹⁹F NMR (Et₂O): d À81.1 (t, J = 10 Hz, 3F),

À81.2 (t, J = 10 Hz, 3F), À110.3 (m, 2F), À119.4 (m, 2F),

121.1 (m, 2F), À121.6 (bs, 12F), À122.5 (m, 4F), À126.1 (m,

1

4F). H NMR (CClF₂CF₂Cl): d 4.78 (t, J = 12 Hz, 2H).

1H,1H-Perﬂuorododecylnonaﬂate (20.5 g, 22.9 mmol) was

treated with KF (6.63 g, 114.4 mol) in TG (110.0 mL) at 200 8C

for 5 h. The resultant solid suspension was dissolved in ether

(ꢀ300.0 mL) and washed with water (4Â 50.0 mL). The ether

layer was dried (anhydrous Na₂SO₄) and evaporated to obtain

1H,1H-perﬂuorododecane as a white crystalline solid (12.0 g,

19.9 mmol, 87%) [mp: 72–73 8C]. ¹⁹F NMR (Et₂O): d À81.2 (t,

J = 9 Hz, 3F), À121.7 (m, 10F), À122.1 (m, 2F), À122.7 (m,

2F), À123.0 (m, 2F), À123.7 (m, 2F), À126.3 (m, 2F), À242.6

(tm, J = 46 Hz, 1F). ¹H NMR (CClF₂CF₂Cl): d 4.74 (dt, J = 46,

11 Hz, 2H).

3.1.2. 1H,1H-Perﬂuoroheptane (C₆F₁₃CH₂F)

By

a similar procedure, 1H,1H-perﬂuoroheptan-1-ol

(32.0 g, 91.4 mmol) was treated with triethylamine (11.07 g,

109.6 mmol) and perﬂuorobutanesulfonyl ﬂuoride (35.8 g,

118.8 mmol) to obtain 1H,1H-perﬂuoroheptylnonaﬂate as a

white crystalline solid (56.1 g, 88.8 mmol, 97%) [mp: 34–

35 8C]. ¹⁹F NMR (CDCl₃): d À81.2 (t, J = 11 Hz, 3F), À81.3 (t,

J = 9 Hz, 3F), À110.2 (t, J = 12 Hz, 2F), À120.1 (m, 2F),

À121.7 (m, 2F), À122.4 (m, 2F), À123.3 (m, 4F), À126.3 (m,

3.2. Synthesis of the perﬂuoropropenylzinc reagent

[CF₃CF CFZnCl] and 1-arylperﬂuoro-prop-1-enes

[CF₃CF CFAr]

A 250 mL three-necked RB ﬁtted with a dry ice/isopropanol

condenser, septum and a low temperature thermometer were

assembled while hot and ﬂushed with nitrogen gas. The ﬂask

was charged with ZnCl₂(3.42 g, 25.0 mmol) and THF

(25.0 mL). The solution was cooled to À78 8C and gaseous

1H,1H-perﬂuoropropane (2.88 mL, 25.0 mmol) was condensed

to the THF solution. A solution of LDA [pre-generated from

diisopropylamine (7.7 mL, 55.0 mmol), and n-BuLi (22.0 mL,

2.5 M) solution in hexanes, 55.0 mmol in THF (25.0 mL)] in

THF was added to this solution slowly (40 min) via a cannula

maintaining the temperature of the contents close to À78 8C.

1

2F), À126.6 (m, 2F). H NMR (CDCl₃): d 4.84 (t, J = 12 Hz,

2H).

1H,1H-Perﬂuoroheptylnonaﬂate (25.0 g, 39.6 mmol) was

treated with KF (11.4 g, 197.8 mol) in TG (200 mL) at 200 8C

for 5 h, followed by isolation as per the above procedure to

afford 1H,1H-perﬂuoroheptane as a colorless liquid (9.85 g,

28.0 mmol, 71%) [bp: 108–110 8C]. ¹⁹F NMR (CDCl₃): d

À81.4 (t, J = 11 Hz, 3F), À122.8 (m, 2F), À123.3 (m, 4F),

À124.3 (m, 2F), À126.7 (m, 2F), À242.2 (tm, J = 46 Hz, 1F).

¹H NMR (CDCl₃): d 4.75 (dt, J = 46, 12 Hz, 2H).

464

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

After the addition was completed, the clear yellow reaction

mixture was stirred for 30 min and then allowed to warm to RT.

The yield of the zinc reagent (mono/bis ꢀ70:30) was 80% and

the E/Z ratio was 89:11. ¹⁹F NMR (THF): [(E)-

CF₃CF CFZnCl]ÁTMEDA d À69.0 (dd, J = 15, 8 Hz, –

À146.9 (ddq, J = 132, 22, 3 Hz, 0.13F, (E)-Ar-CF ), À153.3

(dq, J = 13, 7 Hz, 0.87F, (Z)-R_F-CF ), À157.7 (dq, J = 132,

9 Hz, 0.13F, (E)-R_F-CF ). ¹H NMR (CDCl₃): d 7.49–7.16 (m,

4H, (Z)- and (E)-ArH); GC/MS: 226 (M⁺, 72), 207 (22), 187

(38), 176 (51), 107 (26), 86 (34), 85 (45), 69 (100, BP); HRMS:

calcd. for C₉H₄F₆226.0217, found 226.0221.

CF₃), À133.7 (q, J = 8 Hz,

CFZnCl), À151.0 (q,

J = 16 Hz, CF₃CF ). [(E)-(CF₃CF CF)₂Zn]ÁTMEDA

d

À68.8 (dd, J = 16, 9 Hz, –CF₃), À133.2 (q, J = 9 Hz, CFZn),

150.2 (q, J = 16 Hz, CF₃CF ). [(Z)-CF₃CF CFZnCl]Á

TMEDA/[(Z)-(CF₃CF CF)₂Zn]ÁTMEDA d À69.2 (2 over-

lapped dd, –CF₃), À147.2 (2 overlapped dq, CFZn), À177.4

(2 overlapped dq, CF₃CF ).

3.2.3. (Z)- and (E)-1-(2-methylphenyl)perﬂuoroprop-1-ene

[2-MeC₆H₄CF CFCF₃]

Following the general procedure for the coupling reaction,

the

perﬂuoropropenylzinc

reagent

[CF₃CF CFZnCl]

(10.0 mmol), 2-iodotoluene (1.42 g, 6.5 mmol) and Pd(PPh₃)₄

(0.128 g) were heated at 65 8C for 10 h. Trituration of the

reaction mixture with hexane followed by puriﬁcation of the

crude product chromatography (eluent: hexane) afforded a

mixture of (Z)- and (E)-1-(2-methylphenyl)perﬂuoroprop-1-

ene (Z/E 89:11) as a colorless liquid in 87% (1.25 g, 5.6 mmol)

yield. ¹⁹F NMR (CDCl₃): d À66.0 (dd, J = 10.6, 8 Hz, 2.66F,

(Z)-CF₃–), À67.4 (dd, J = 22, 11 Hz, 0.35F, (E)-CF₃–), À109.6

(quintet, 7 Hz, 0.89F, (Z)-Ar-CF ), À146.1 (dq, J = 132,

22 Hz, 0.11F, (E)-Ar-CF ), À154.4 (dqq, J = 13, 10, 3 Hz,

0.89F, (Z)-R_F-CF ), À169.1 (dqm, J = 132, 11 Hz, 0.11F, (E)-

R_F-CF ). ¹H NMR (CDCl₃): d 7.42–7.23 (m, 4H, (Z)- and (E)-

ArH), 2.37 (d, J = 3 Hz, 3H, (Z)- and (E)-CH₃): GC/MS: 222

(M⁺, 53), 153 (32), 151 (30), 133 (100, BP), 69 (23); HRMS:

calcd. for C₁₀H₇F₅222.0468, found 222.0471.

The THF solution of perﬂuoropropenylzinc reagent

[CF₃CF CFZnCl] (10.0 mmol), aryl iodide (6–7 mmol) and

Pd(PPh₃)₄were heated at 65 8C in a 250 mL three-necked RB

ﬁtted with a reﬂux condenser, septa and stopper. The reaction

mixture was cooled to RT and the products were triturated with

either pentane or hexane (4Â 20 mL). Careful removal of the

solvent under mild vacuum followed by puriﬁcation of the

crude product either by distillation or column chromatography

(silica gel) afforded the pure 1-arylperﬂuoropropenes.

3.2.1. (Z)- and (E)-1-phenylperﬂuoroprop-1-ene

[C₆H₅CF CFCF₃]

Following the general procedure for the coupling reaction,

the THF solution of perﬂuoropropenylzinc reagent

[CF₃CF CFZnCl] (10.3 mmol), iodobenzene (1.34 g,

6.6 mmol) and Pd(PPh₃)₄(0.131 g) were heated at 65 8C for

8 h. The reaction mixture was then cooled to RT and triturated

with pentane (4Â 20 mL). The crude product was then

chromatographed on silica gel (eluent: pentane) to obtain a

mixture of (Z)- and (E)-1-phenylperﬂuoroprop-1-ene (Z/E

87:13) as a colorless liquid in 80% (1.1 g, 5.3 mmol) yield [53].

¹⁹F NMR (CDCl₃): d À66.1 (dd, J = 12, 7 Hz, 2.6F, (Z)-CF₃–),

À67.4 (dd, J = 21, 9 Hz, 0.4F, (E)-CF₃–), À109.5 (quintet,

J = 10 Hz, 0.86F, (Z)-Ar-CF ), À146.5 (dq, J = 132, 23 Hz,

0.14F, (E)-Ar-CF ), À155.0 (dq, J = 13, 9 Hz, 0.86F, (Z)-R_F-

3.2.4. (Z)- and (E)-1-(3-methoxyphenyl)perﬂuoroprop-1-

ene [3-MeOC₆H₄CF CFCF₃]

Following the general procedure for the coupling reaction,

the

perﬂuoropropenylzinc

reagent

[CF₃CF CFZnCl]

(10.0 mmol), 3-iodoanisole (1.52 g, 6.5 mmol) and Pd(PPh₃)₄

(0.128 g) were heated at 65 8C for 6 h. Trituration of the

reaction mixture with hexane followed by puriﬁcation of the

crude product by chromatography (eluent: 5% CH₂Cl₂–hexane)

afforded a mixture of (Z)- and (E)-1-(3-methoxyphenyl)per-

ﬂuoroprop-1-ene (Z/E 90:10) as a colorless liquid in 78%

(1.21 g, 5.08 mmol) yield. ¹⁹F NMR (CDCl₃): d À67.0 (dd,

J = 13.1, 8 Hz, 2.7F, (Z)-CF₃–), À67.8 (dd, J = 22, 12 Hz, 0.3F,

(E)-CF₃–), À106.2 (m, 0.9F, (Z)-Ar-CF ), À128.8 (dq,

J = 141, 21 Hz, 0.1F, (E)-Ar-CF ), À155.3 (quintet,

J = 13 Hz, 0.9F, (Z)-R_F-CF ), À168.6 (dq, J = 141, 10 Hz,

0.1F, (E)-R_F-CF ). ¹H NMR (CDCl₃): d 7.37–6.98 (m, 4H, (Z)-

and (E)-ArH), 3.82 (s, 0.3H, (E)-OCH₃), 3.81 (s, 2.7H, (Z)-

OCH₃); GC/MS: 239 (M⁺+ 1, 47), 238 (M⁺, BP, 100), 219 (37),

208 (55), 207 (41), 187 (45), 175 (50), 169 (37), 158 (65), 145

(89), 139 (43), 125 (58), 119 (43), 125 (58), 119 (43), 69 (40);

HRMS: calcd. for C₁₀H₇F₅O 238.0417, found 238.0417.

1

CF ), À169.9 (dq, J = 131, 11 Hz, 0.14F, (E)-R_F-CF ). H

NMR (CDCl₃): d 7.68–7.41 (m, 5H, (Z)- and (E)-ArH); GC/

MS: 208 (M⁺, 39), 207 (20), 169 (28), 158 (31), 84 (32), 69

(100, BP). HRMS: calcd. for C₉H₅F₅208.0311, found

208.0310.

3.2.2. (Z)- and (E)-1-(4-ﬂuorophenyl)perﬂuoroprop-1-ene

[4-FC₆H₄CF CFCF₃]

Following the general procedure for the coupling reaction,

the

perﬂuoropropenylzinc

reagent

[CF₃CF CFZnCl]

(10.3 mmol), 4-ﬂuoroiodobenzene (1.46 g, 6.6 mmol) and

Pd(PPh₃)₄(0.131 g) were heated at 65 8C for 8 h. Trituration

of the reaction mixture with pentane followed by puriﬁcation of

the crude product by chromatography (eluent: pentane)

afforded a mixture of (Z)- and (E)-1-(4-ﬂuorophenyl)perﬂuor-

oprop-1-ene (Z/E 87:13) as a colorless liquid in 77% (1.15 g,

5.0 mmol) yield. ¹⁹F NMR (CDCl₃): d À66.2 (dd, J = 13, 8 Hz,

2.6F, (Z)-CF₃–), À67.6 (dd, J = 22, 8 Hz, 0.4F, (E)-CF₃–),

À110.7 (quintet, J = 8 Hz, 0.87F, (Z)-Ar-CF ), À110.7 (m,

0.87F, (Z)-p-FC₆H₄–), À111.5 (m, 0.13F, (E)-p-FC₆H₄–),

3.2.5. (Z)- and (E)-1-(3-

triﬂuoromethylphenyl)perﬂuoroprop-1-ene

[3-F₃CC₆H₄CF CFCF₃]

Following the general procedure for the coupling reaction,

the perﬂuoropropenylzinc reagent [CF₃CF CFZnCl] (10.0

mmol), 3-iodobenzotriﬂuoride (1.76 g, 6.5 mmol) and

Pd(PPh₃)₄(0.129 g) were heated at 65 8C for 8 h. Trituration

of the reaction mixture with hexane followed by puriﬁcation of

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

465

the crude product by chromatography (eluent: hexane) afforded

3.3.2. (Z)- and (E)-1-(4-ﬂuorophenyl)perﬂuorobut-1-ene

[p-FC₆H₄CF CFC₂F₅]

a mixture of (Z)- and (E)-1-(3-triﬂuoromethylphenyl)perﬂuor-

oprop-1-ene (Z/E 88:12) as a colorless liquid in 82% (1.47 g,

5.33 mmol) yield. ¹⁹F NMR (CDCl₃): d À63.6 (s, 3F, (Z)- and

(E)-Ar-CF₃–), À66.2 (dd, J = 13, 8 Hz, 2.6F, (Z)-CF₃–), À67.6

(dd, J = 22, 10 Hz, 0.4F, (E)-CF₃–), À111.2 (quintet, 8 Hz,

0.86F, (Z)-Ar-CF ), À147.3 (dq, J = 132, 22 Hz, 0.14F, (E)-

Ar-CF ), À152.5 (dq, J = 13, 8 Hz, 0.86F, (Z)-R_F-CF ),

The perﬂuorobutenylzinc reagent [C₂F₅CF CFZnCl]

(9.57 mmol), 4-ﬂuoroiodobenzene (1.38 g, 6.2 mmol) and

Pd(PPh₃)₄(0.123 g) were heated at 65 8C for 5 h. Trituration

of the reaction mixture with hexane followed by puriﬁcation of

the crude product by chromatography (eluent: hexane) afforded

a mixture of (Z)- and (E)-1-(4-ﬂuorophenyl)perﬂuorobut-1-ene

(Z/E 94:6) as a colorless liquid in 81% (1.39 g, 5.03 mmol)

yield. ¹⁹F NMR (CDCl₃): d À84.0 (dt, J = 6, 4 Hz, 2.78F, (Z)-

CF₃–), À85.0 (m, 0.23F, (E)-CF₃–), À100.9 (dt, J = 11, 6 Hz,

0.93F, (Z)-Ar-CF ), À107.3 (m, 0.06F, (E)-Ar-F), À107.4 (m,

0.94F, (Z)-Ar-F), À117.0 (d, J = 17 Hz, 1.86F, (Z)-CF₂–),

À120.0 (ddq, J = 27, 12, 2 Hz, 0.14 F, (E)-CF₂–), À144.7 (dtq,

J = 133, 27, 6 Hz, 0.07F, (E)-Ar-CF ), À152.5 (m, 0.93F, (Z)-

1

À167.5 (dq, J = 132, 11 Hz, 0.14F, (E)-R_F-CF ). H NMR

(CDCl₃): d 7.95–7.58 (m, 4H, (Z)- and (E)-ArH); GC/MS: 276

(M⁺, 37), 226 (34), 207 (46), 187 (39), 138 (21), 86 (44), 84

(67), 69 (100, BP); HRMS: calcd. for C₁₀H₄F₈276.0185, found

276.0177.

3.3. Synthesis of the perﬂuorobutenylzinc reagent

[C₂F₅CF CFZnCl] and synthesis of 1-arylperﬂuoro-1-

butenes [C₂F₅CF CFAr]

1

R_F-CF ), À168.7 (dm, J = 132 Hz, 0.07F, (E)-R_F-CF ). H

NMR (CDCl₃): d 7.45 (m, 2H, (Z)- and (E)-ArH), 7.14 (m, 2H,

(Z)- and (E)-ArH); GC/MS: 276 (M⁺, 30), 207 (66), 187 (BP,

100), 86 (47), 84 (70), 69 (74), 51 (51); HRMS: calcd. for

C₁₀H₄F₈276.0185, found 276.0190.

A 250 mL three-necked RB ﬁtted with a dry ice/isopropanol

condenser, septum and a low temperature thermometer was

assembled while hot and ﬂushed with nitrogen gas. The ﬂask

was charged with ZnCl₂(1.70 g, 12.5 mmol) and THF

(15.0 mL). The solution was cooled to À788C and gaseous

1H,1H-perﬂuorobutane (2.53 mL, 12.5 mmol) was condensed

to the THF solution. LDA [pre-generated from diisopropyla-

mine (3.85 mL, 27.5 mmol), and n-BuLi (11.0 mL) 2.5 M

solution in hexanes, 27.5 mmol in THF (15 mL)] was added to

this solution slowly (ꢀ30 min) through a cannula maintaining

the temperature of the contents at À78 8C. The clear golden

yellow reaction mixture was then stirred À78 8C for an

additional 30 min and allowed to warm to RT. The yield of the

zinc reagent (mono/bis ꢀ65:35) was 76% and the E/Z ratio was

94:6. ¹⁹F NMR (THF): [(E)-C₂F₅CF CFZnCl]ÁTMEDA d

À84.3 (m, –CF₃), À118.7 (d, J = 20.5 Hz, –CF₂), À128.7 (bs,

CFZnCl), À147.8 (m, CF₃CF ) [((E)-CF₃CF CF)₂Zn]Á

TMEDA d À84.1 (m, –CF₃), À119.2 (d, J = 21.4 Hz, –

CF₂), À129.1 (bs, CFZn), À149.3 (m, CF₃CF ).

3.3.3. (Z)- and (E)-1-(2-isopropylphenyl)perﬂuorobut-1-

ene [2-(CH₃)₂CHC₆H₄CF CFC₂F₅]

The perﬂuorobutenylzinc reagent solution [C₂F₅CF C

FZnCl] (8.0 mmol), 2-isopropyliodobenzene (1.22 g, 5.0

mmol) and Pd(PPh₃)₄(0.100 g) were heated at 65 8C for

18 h. Trituration of the reaction mixture with hexane followed

by puriﬁcation of the crude product by chromatography (eluent:

hexane) afforded a mixture of (Z)- and (E)-1-(2-isopropylphe-

nyl)perﬂuorobut-1-ene (Z/E 94:6) as a colorless liquid in 71%

(1.05 g, 3.5 mmol) yield. ¹⁹F NMR (CDCl₃): d À84.1 (dt, J = 7,

3.0 Hz, 2.8F, (Z)-CF₃–), À85.1 (m, 0.18F, (E)-CF₃), À95.6 (d,

J = 14 Hz, 0.94F, (Z)-Ar-CF ), À117.6 (d, J = 17 Hz, 1.88F,

(Z)-CF₂–), À120.5 (ddq, J = 25, 13, 2 Hz, 0.12F, (E)-CF₂–),

À122.0 (dtm, J = 143, 26 Hz, 0.06F, (E)-Ar-CF ), À153.2 (m,

0.94F, (Z)-R_F-CF ), À166.0 (dm, J = 143 Hz, 0.06F, (E)-R_F-

1

CF ). H NMR (CDCl₃): d 7.52–7.19 (m, 4H, (Z)- and (E)-

ArH), 3.03 (m, 0.94H, (Z)-(CH₃)₂CH–), 2.63 (m, 0.06H, (E)-

(CH₃)₂CH–), 1.26 (d, J = 7 Hz, 0.35H, (E)-(CH₃)₂–), 1.25 (d,

J = 7 Hz, 0.5.65H, (Z)-(CH₃)₂–); GC/MS: 300 (M⁺, 75), 285

(BP, 100), 267 (20), 245 (36), 166 (26), 151 (46), 146 (84), 133

(33), 129 (44), 115 (23), 69 (94); HRMS: calcd. for C₉H₄F₅

300.0749, found 300.0750.

3.3.1. (Z)- and (E)-1-phenylperﬂuorobut-1-ene

[C₆H₅CF CFC₂F₅]

The perﬂuorobutenylzinc reagent solution [C₂F₅CF

CFZnCl] (8.94 mmol), iodobenzene (1.1 g, 5.4 mmol) and

Pd(PPh₃)₄(0.107 g) were heated at 65 8C for 6 h. Trituration of

the reaction mixture with hexane followed by puriﬁcation of the

crude product by chromatography (eluent: hexane) afforded a

mixture of (Z)- and (E)-1-phenylperﬂuorobut-1-ene (Z/E 93:7)

as a colorless liquid in 89% (1.24 g, 4.80 mmol) yield. ¹⁹F

NMR (CDCl₃): d À84.0 (dt, J = 5, 2 Hz, 2.76F, (Z)-CF₃–),

À85.0 (m, 0.24F, (E)-CF₃–), À101.5 (d, J = 10 Hz, 0.92F, (Z)-

Ar-CF ), À117.1 (d, J = 17 Hz, 1.84F, (Z)-CF₂), À120.0 (ddq,

J = 27, 11.4, 3 Hz, 0.16 F, (E)-CF₂–), À145.1 (dtq, J = 132, 26,

6 Hz, 0.08F, (E)-Ar-CF ), À153.5 (m, 0.92F, (Z)-R_F-CF ),

À168.5 (dm, J = 132 Hz, 0.08F, (E)-R_F-CF ). ¹H NMR

(CDCl₃): d 7.54–7.40 (m, 5H, (Z)- and (E)-ArH); GC/MS:

258 (M⁺, 41), 189 (60), 169 (100, BP), 69 (38); HRMS: calcd.

for C₁₀H₅F₇258.0279, found 258.0276.

3.3.4. (Z)- and (E)-1-(3-

triﬂuoromethylphenyl)perﬂuorobut-1-ene [3-

F₃CC₆H₄CF CFC₂F₅]

The perﬂuorobutenylzinc reagent solution [C₂F₅CF C

FZnCl] (8.0 mmol), 3-iodobenzotriﬂuoride (1.35 g, 5.0 mmol)

and Pd(PPh₃)₄(0.100 g) were heated at 65 8C for 8 h.

Trituration of the reaction mixture with hexane followed by

puriﬁcation of the crude product by chromatography (eluent:

hexane) afforded a mixture of (Z)- and (E)-1-(3-triﬂuoro-

methylphenyl)perﬂuorobut-1-ene (Z/E 93:7) as a colorless

liquid in 78% (1.20 g, 4.1 mmol) yield. ¹⁹F NMR (CDCl₃): d

À63.6 (s, 2.75F, (Z)-ArCF₃), À63.7 (s, 0.25F, (E)-ArCF₃),

À84.0 (dt, J = 4, 2 Hz, 2.75F, (Z)-CF₃–), À85.0 (m, 0.26F, (E)-

466

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

CF₃–), À103.3 (bd, J = 10 Hz, 0.92F, (Z)-Ar-CF ), À117.2 (d,

J = 16 Hz, 1.84F, (Z)-CF₂–), À120.2 (dd, J = 26, 12 Hz, 0.16F,

(E)-CF₂–), À145.8 (dtq, J = 133, 28, 6 Hz, 0.08F, (E)-Ar-

CF ), À151.0 (m, 0.92F, (Z)-R_F-CF ), À168.7 (dm,

7.58 (m, 4H, (Z)- and (E)-ArH); GC/MS: 326 (M⁺, 64), 307

(20), 257 (100, BP), 237 (82), 188 (25), 187 (41), 169 (32), 69

(34); HRMS: calcd. for C₁₁H₄F₁₀326.0153, found 326.0154.

CF₃–), À99.0 (d, J = 13 Hz, 0.95F, (Z)-Ar-CF ), À114.6 (q,

J = 13 Hz, 1.9F, (Z)-CF₂–), À117.4(m, 0.1F, (E)-CF₂–), À123.7

(m, 1.9F, (Z)-CF₂–), À125.0 (m, 0.1F, (E)-CF₂–), À126.8 (m,

1.9F, (Z)-CF₂–), À126.8 (m, 0.1F, (E)-CF₂–), À144.5 (dm, not

resolved, 0.05F, (E)-Ar-CF ), À152.3 (m, 0.95F, (Z)-R_F-CF ),

À165.4 (dm, J = 142 Hz, 0.05F, (E)-R_F-CF ). ¹H NMR

(CDCl₃): d 7.45–7.20 (m, 4H, (Z)- and (E)-ArH), 2.37 (d,

J = 2.7 Hz, 3H, (Z)- and (E)-CH₃); GC/MS: 372 (M⁺, 67), 183

(100, BP), 169 (24), 153 (31), 151 (56), 134 (43), 133 (83), 69

(40); HRMS: calcd. for C₁₃H₇F₁₁372.0372, found 372.0371.

1

J = 134 Hz, 0.08F, (E)-R_F-CF ). H NMR (CDCl₃): d 7.92–

3.4. Synthesis of the perﬂuorohexenylzinc reagent

[C₄F₉CF CFZnCl] and synthesis of 1-arylperﬂuoro-1-

hexene [n-C₄F₉CF CFAr]

3.4.3. (Z)- and (E)-1-(4-methoxyphenyl)perﬂuorohex-1-ene

[4-MeOC₆H₄CF CFC₄F₉]

Following the standard procedure for the preparation of

perﬂuoroalkenylzinc reagents, metallation of 1H,1H-perﬂuor-

ohexane (2.82 g, 9.3 mmol) with LDA (20.5 mmol) in presence

of ZnCl₂(1.27 g, 9.3 mmol) afforded the perﬂuorohexenylzinc

reagent (mono/bis ꢀ70:30) as a dark-brown solution in 75%

yield with E/Z ratio 96:4. ¹⁹F NMR (THF): [(E)-

C₄F₉CF CFZnCl]ÁTMEDA d À81.5 (t, J = 10 Hz, –CF₃),

À115.4 (m, CFCF₂), À123.3 (m, –CF₂), À123.3 (m, –CF₂),

À126.1 (s, CFZnCl), À126.7 (m, CF₂), À152.1 (m, CF₂CF )

[((E)-C₄F₉CF CF)₂Zn]ÁTMEDA d À81.6 (t, J = 10 Hz, –CF₃),

À114.8 (m, CFCF₂), À122.4 (m, CF₂), À123.0 (m, –CF₂),

À125.5 (s, CFZn), À126.5 (m, CF₂), À151.2 (m, CF₂CF ).

The perﬂuorohexenylzinc reagent solution [C₄F₉CF C

FZnCl] (1.5 mmol), 4-iodoanisole (0.234 g, 1.0 mmol) and

Pd(PPh₃)₄(0.025 g) were heated at 65 8C for 6 h. Trituration of

the reaction mixture with hexane followed by puriﬁcation of the

crude product by chromatography (eluent: 5% CH₂Cl₂–hexane)

produced a mixture of (Z)- and (E)-1-(4-methoxyphenyl)per-

ﬂuorohex-1-ene (Z/E 96:4) as a colorless liquid in 79%

(0.306 g, 0.79 mmol) yield. ¹⁹F NMR (CDCl₃): d À81.4 (t,

J = 9 Hz, 3F, (Z)- and (E)-CF₃–), À98.4 (d, J = 12 Hz, 0.95F,

(Z)-Ar-CF ), À113.7 (q, J = 15 Hz, 1.9F, (Z)-CF₂–), À116.8

(m, 0.1F, (E)-CF₂–), À123.4 (m, 1.9F, (Z)-CF₂–), À125.0 (m,

0.1F, (E)-CF₂–), À126.8 (m, 1.9F, (Z)-CF₂–), À126.9 (m, 0.1F,

(E)-CF₂–), À144.5 (dm, J = 131 Hz, 0.05F, (E)-Ar-CF ),

À153.0 (m, 0.95F, (Z)-R_F-CF ), À170.0 (dm, J = 131 Hz,

3.4.1. (Z)- and (E)-1-phenylperﬂuorohex-1-ene

[C₆H₅CF CFC₄F₉]

1

0.05F, (E)-R_F-CF ). H NMR (CDCl₃): d 7.65 (d, J = 9 Hz,

The perﬂuorohexenylzinc reagent solution [C₄F₉CF C

FZnCl] (1.5 mmol), iodobenzene (0.204 g, 1.0 mmol) and

Pd(PPh₃)₄(0.025 g) were heated at 65 8C for 8 h. Trituration of

the reaction mixture with hexane followed by puriﬁcation of the

crude product by chromatography over silica gel (eluent:

hexane) afforded a mixture of (Z)- and (E)-1-phenylperﬂuor-

ohex-1-ene (Z/E 96:4) as a colorless liquid in 81% (0.291 g,

0.81 mmol) yield [42]. ¹⁹F NMR (CDCl₃): d À81.4 (t,

J = 10 Hz, 3F, (Z)- and (E)-CF₃–), À99.9 (d, J = 10 Hz,

0.96F, (Z)-Ar-CF ), À113.9 (q, J = 14 Hz, 1.92F, (Z)-CF₂),

À117.1 (m, 0.08F, (E)-CF₂–), À123.4 (m, 1.92F, (Z)-CF₂–),

À125.0 (m, 0.08F, (E)-CF₂–), À126.8 (m, 1.92F, (Z)-CF₂–),

À126.9 (m, 0.08F, (E)-CF₂–), À144.6 (dm, J = 132 Hz, 0.04F,

(E)-Ar-CF ), À152.3 (m, 0.96F, (Z)-R_F-CF ), À167.3 (dm,

0.10H, (E)-ArH), 7.37 (d, J = 8 Hz, 1.8H, (Z)-ArH), 7.00 (d,

J = 9 Hz, 0.10H, (E)-ArH), 6.93 (d, J = 9 Hz, 1.8H, (Z)-ArH),

3.86 (s, 0.15H, (E)-Ar-OCH₃), 3.85 (2.85H, (E)-Ar-OCH₃);

GC/MS: 388 (M⁺, 41), 369 (15), 219 (BP, 100), 199 (59), 169

(22), 69 (24); HRMS: calcd. for C₁₃H₇F₁₁O 388.0321, found

388.0315.

3.4.4. (Z)- and (E)-1-(3-

triﬂuoromethylphenyl)perﬂuorohex-1-ene

[3-CF₃C₆H₅CF CFC₄F₉]

The perﬂuorohexenylzinc reagent solution [C₄F₉CF C

FZnCl]

(1.5 mmol),

3-iodobenzotriﬂuoride

(0.272 g,

1.0 mmol) and Pd(PPh₃)₄(0.025 g) were heated at 65 8C for

8 h. Trituration of the reaction mixture with hexane followed by

puriﬁcation of the crude product by chromatography (eluent:

hexane) produced a mixture of (Z)- and (E)-1-(3-triﬂuoro-

methylphenyl)perﬂuorohex-1-ene (Z/E 95:5) as a colorless

liquid in 78% (0.332 g, 0.78 mmol) yield. ¹⁹F NMR (CDCl₃): d

À63.61 (s, 0.15F, (E)-ArCF₃), À63.65 (s, 2.85F, (Z)-ArCF₃),

À81.4 (m, 3F, (Z)- and (E)-CF₃–), À101.9 (bs, 0.95F, (Z)-Ar-

CF ), À114.1 (m, 1.92F, (Z)-CF₂–), À117.3 (m, 0.1F, (E)-

CF₂–), À123.4 (m, 1.9F, (Z)-CF₂–), À124.9 (m, 0.1F, (E)-

CF₂–), À126.8 (m, 1.9F, (Z)-CF₂–), À126.8 (m, 0.1F, (E)-

CF₂–), À144.5 (dm, J = 132 Hz, 0.05F, (E)-Ar-CF ), À149.7

(m, 0.95F, (Z)-R_F-CF ), À169.7 (dm, J = 132 Hz, 0.05F, (E)-

R_F-CF ). ¹H NMR (CDCl₃): d 7.97–7.44 (m, 4H, (Z)- and (E)-

ArH); GC/MS: 426 (M⁺, 40), 407 (28), 257 (BP, 100), 237 (92),

188 (55), 187 (72), 169 (73), 69 (59). HRMS: calcd. for

C₁₃H₄F₁₄426.0089, found 426.0087.

1

J = 132 Hz, 0.04F, (E)-R_F-CF ). H NMR (CDCl₃): d 7.56–

7.40 (m, 5H, (Z)- and (E)-ArH); GC/MS: 358 (M⁺, 5), 189 (59),

169 (100, BP), 69 (34); HRMS: calcd. for C₁₂H₅F₁₁358.0216,

found 358.0222.

3.4.2. (Z)- and (E)-1-(2-methylphenyl)perﬂuorohex-1-ene

[2-MeC₆H₄CF CFC₄F₉]

The perﬂuorohexenylzinc reagent solution [C₄F₉CF C

FZnCl] (1.5 mmol), 2-iodotoulene (0.218 g, 1.0 mmol) and

Pd(PPh₃)₄(0.025 g) were heated at 65 8C for 15 h. Trituration of

the reaction mixture with hexane followed by puriﬁcation of the

crude product by chromatography (eluent: hexane) afforded a

mixture of (Z)- and (E)-1-(2-methylphenyl)perﬂuorohex-1-ene

(Z/E 96:4) as a colorless liquid in 81% (0.302 g, 0.81 mmol)

yield. ¹⁹F NMR (CDCl₃): d À81.4 (t, J = 10 Hz, 3F, (Z)- and (E)-

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

467

3.5. Synthesis of the perﬂuoroheptenylzinc reagent

[C₅F₁₁CF CFZnCl] and synthesis of 1-arylperﬂuoro-1-

heptene [n-C₅F₁₁CF CFAr]

1.0 mmol) and Pd(PPh₃)₄(0.025 g) were heated at 65 8C for

12 h, Trituration of the reaction mixture with hexane followed

by puriﬁcation of the crude product by chromatography (eluent:

hexane) afforded pure (Z)-1-(3-triﬂuoromethylphenyl)perﬂuor-

ohept-1-ene as a colorless liquid in 86% (0.408 g, 0.86 mmol)

yield. ¹⁹F NMR (CDCl₃): d À63.7 (s, 3F, Ar-CF₃), À81.4 (t,

J = 10 Hz, 3F, CF₃–), À101.9 (d, J = 7.0 Hz, 1F, Ar-CF ),

À113.9 (q, J = 12 Hz, 2F, CF₂–), À122.6 (m, 2F, CF₂–),

À123.3 (m, 2F, CF₂–), À126.7 (m, 2F, CF₂–), À149.7 (m, 1F,

R_F-CF ). ¹H NMR (CDCl₃): d 7.80 (d, J = 8 Hz, 1H), 7.73 (s,

1H), 7.67–7.57 (m, 2H); GC/MS: 476 (M⁺, 58), 457 (48), 258

(36), 257 (100, BP), 237 (84), 188 (57), 187 (67), 169 (72), 119

(31), 69 (77); HRMS: calcd. for C₁₄H₄F₁₆476.0058, found

476.0061.

Following the standard procedure for the preparation of

perﬂuoroalkenylzinc reagent, metallation of 1H,1H-perﬂuoro-

heptane (3.54 g, 10.1 mmol) with LDA (22.2 mmol) in presence

of ZnCl₂(1.39 g, 10.1 mmol) and obtained the zinc reagent

(mono/bis ꢀ60:40)as a pink-brownsolutionin 83%yieldwith E/

Z ratio 99:1. ¹⁹F NMR (THF): [(E)-C₅F₁₁CF CFZnCl]ÁTMEDA

d À81.5 (t, J = 9 Hz, –CF₃), À114.8 (m, –CF₂), À122.6 (m, –

CF₂), À123.3 (m, –CF₂), À126.6 (m, CF₂), À127.8 (s,

CFZnCl), À146.5 (m, CF₂CF ); [((E)-C₅F₁₁CF CF)₂

Zn]ÁTMEDA d À81.6 (t, J = 10 Hz, –CF₃), À115.5 (m, –

CF₂), À122.3 (m, –CF₂), À123.0 (m, –CF₂), À126.6 (m, CF₂),

À127.4 (s, CFZn), À148.3 (m, CF₂CF ).

3.5.4. (Z)-1-(4-Methoxyphenyl)perﬂuorohept-1-ene [4-

MeOC₆H₄CF CFC₅F₁₁]

3.5.1. (Z)-1-Phenylperﬂuorohept-1-ene

[C₆H₅CF CFC₅F₁₁]

The perﬂuoroheptenylzinc reagent solution [C₅F₁₁CF C

FZnCl] (1.7 mmol), 4-iodoanisole (0.234 g, 1.0 mmol) and

Pd(PPh₃)₄(0.025 g) were heated at 65 8C for 8 h. Trituration

of the reaction mixture with hexane followed by puriﬁcation

of the crude product by chromatography (eluent: 5%

CH₂Cl₂–hexane) afforded pure (Z)-1-(4-methoxyphenyl)per-

ﬂuorohept-1-ene as a colorless liquid in 92% (0.402 g,

0.92 mmol) yield. ¹⁹F NMR (CDCl₃): d À81.3 (t, J = 10 Hz,

3F, CF₃–), À98.4 (d, J = 12 Hz, 1F, Ar-CF ), À113.5 (q,

J = 14 Hz, 2F, CF₂–), À122.6 (m, 2F, CF₂–), À123.3 (m, 2F,

The perﬂuoroheptenylzinc reagent solution [C₅F₁₁

CF CFZnCl] (1.7 mmol), iodobenzene (0.204 g, 1.0 mmol)

and Pd(PPh₃)₄(0.025 g) were heated at 65 8C for 8 h.

Trituration of the reaction mixture with hexane followed by

puriﬁcation of the crude product by chromatography (eluent:

hexane) afforded pure (Z)-1-phenylperﬂuorohept-1-ene as a

colorless liquid in 89% (0.363 g, 0.89 mmol) yield. ¹⁹F NMR

(CDCl₃): d À81.3 (t, J = 10 Hz, 3F, CF₃–), À99.9 (d,

J = 10 Hz, 1F, Ar-CF ), À113.7 (q, J = 12 Hz, 2F, CF₂–),

À122.7 (m, 2F, CF₂–), À123.4 (m, 2F, CF₂–), À126.7 (m, 2F,

CF₂–), À152.2 (m, 1F, R_F-CF ). ¹H NMR (CDCl₃): d 7.45–

7.20 (m, 5H, ArH); GC/MS: 408 (M⁺, 31), 189 (73), 169 (100,

BP), 69 (62); HRMS: calcd. for C₁₃H₅F₁₃408.0184, found

408.0186.

1

CF₂–), À126.7 (m, 2F, CF₂–), À152.9 (m, 2F, R_F-CF ). H

NMR (CDCl₃): d 7.38 (dd, J = 8, 1 Hz, 2H), 6.94 (d,

J = 8 Hz, 2H), 3.84 (s, 3H); GC/MS: 438 (M⁺, 31), 189 (73),

169 (100, BP), 69 (62); HRMS: calcd. for C₁₄H₇F₁₃

438.0289, found 438.0289.

3.5.2. (Z)-1-(4-Fluorophenyl)perﬂuorohept-1-ene [4-

FC₆H₄CF CFC₅F₁₁]

3.5.5. (Z)- and (E)-1-(2-methyl-6-

nitrophenyl)perﬂuorohept-1-ene

[2-Me(6-NO₂)C₆H₃CF CFC₅F₁₁]

The perﬂuoroheptenylzinc reagent solution [C₅F₁₁CF C

FZnCl] (1.7 mmol), 4-ﬂuoroiodobenzene (0.222 g,

1.0 mmol) and Pd(PPh₃)₄(0.025 g) were heated at 65 8C

for 12 h. Trituration of the reaction mixture with hexane

followed by puriﬁcation of the crude product by chromato-

graphy (eluent: hexane) afforded pure (Z)-1-(4-ﬂuorophe-

nyl)perﬂuorohept-1-ene as a colorless liquid in 91% (0.390 g,

0.91 mmol) yield. ¹⁹F NMR (CDCl₃): d À81.3 (t, J = 11 Hz,

3F, CF₃–), À99.9 (dm, not resolved, 1F, Ar-CF ), À107.4

(m, 1F, ArF–), À113.7 (q, J = 13 Hz, 2F, CF₂–), À122.7 (m,

2F, CF₂–), À123.4 (m, 2F, CF₂–), À126.7 (m, 2F, CF₂–),

À151.2 (m, 1F, R_F-CF ). ¹H NMR (CDCl₃): d 7.47 (t,

distorted, 2H), 7.14 (tm, J = 8 Hz, 2H); GC/MS: 426 (M⁺,

48), 407 (14), 207 (100, BP), 187 (91), 169 (36), 138 (34),

119 (32), 69 (78). HRMS: calcd. for C₁₃H₄F₁₄426.0089,

found 426.0099.

The perﬂuoroheptenylzinc reagent solution [C₅F₁₁CF C

FZnCl] (1.7 mmol), 2-methyl-6-nitroiodobenzene (0.263 g,

1.0 mmol) and Pd(PPh₃)₄(0.025 g) were heated at 65 8C for

24 h. Trituration of the reaction mixture with hexane followed

by puriﬁcation of the crude product by chromatography (eluent:

hexane) afforded a mixture of (Z)- and the (E)-1-(2-methyl-6-

nitrophenyl)perﬂuorohept-1-ene as a colorless liquid in 31%

(0.145 g, 0.31 mmol) yield with Z/E ratio 91:9. ¹⁹F NMR

(CDCl₃): d À81.3 (t, J = 10 Hz, 3F, (Z)- and (E)-CF₃–), À102.8

(bd, J = 8 Hz, 0.9F, (Z)-Ar-CF ), À114.6 (q, J = 12 Hz, 1.8F,

(Z)-CF₂–), À117.4 (m, 0.18F, (E)-CF₂–), À122.9 (m, 1.8F, (Z)-

CF₂–), À123.2 (m, 0.36F, 2(E)-CF₂–), À123.3 (m, 1.8F, (Z)-

CF₂–), À124.1 (m, 0.18F, (E)-CF₂–), À126.6 (m, 1.8F, (Z)-

CF₂–), À129.2 (dm, J = 142 Hz, 0.09F, (E)-Ar-CF ), À149.1

(m, 0.9F, (Z)-R_F-CF ), À162.0 (dm, J = 142 Hz, 0.09F, (E)-

R_F-CF ). ¹H NMR (CDCl₃): d 8.09 (s, 1H), 8.02 (d, J = 9 Hz,

1H), 7.44 (d, J = 8 Hz, 1H), 2.42 (d, J = 2 Hz, 3H); GC/MS:

467 (M⁺, 11), 248 (10), 202 (44), 182 (21), 151 (43), 119 (31),

69 (100, BP); HRMS: calcd. for C₁₄H₆NO₂F₁₃467.0191, found

467.0192.

3.5.3. (Z)-1-(3-Triﬂuoromethylphenyl)perﬂuoro-1-heptene

[3-CF₃C₆H₄CF CFC₅F₁₁]

The perﬂuoroheptenylzinc reagent solution [C₅F₁₁

CF CFZnCl] (1.7 mmol), 3-iodobenzotriﬂuoride (0.234 g,

468

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

3.6. Synthesis of the perﬂuorooctenylzinc reagent

[C₅F₁₁CF CFZnCl] and synthesis of 1-arylperﬂuoro-1-

octenes [n-C₆F₁₃CF CFAr]

colorless liquid in 95% (0.795 g, 1.5 mmol) yield. ¹⁹F NMR

(CDCl₃): d À63.7 (s, 3F, Ar-CF₃), À81.3 (t, J = 10 Hz, 3F,

CF₃–), À101.8 (d, J = 7 Hz, 1F, Ar-CF ), À113.8 (q,

J = 13 Hz, 2F, CF₂–), À122.5 (m, 4F, 2CF₂–), À123.3 (m,

2F, CF₂–), À126.6 (m, 2F, CF₂–), À149.6 (m, 1F, R_F-CF ). ¹H

NMR (CDCl₃): d 7.80 (d, J = 7 Hz, 1H), 7.73 (s, 1H), 7.64 (t,

distorted, 1H), 7.58 (d, J = 8 Hz, 1H); GC/MS: 476 (M⁺, 30),

507 (20), 257 (50), 237 (59), 187 (25), 169 (32), 119 (35), 69

(100, BP); HRMS: calcd. for C₁₅H₄F₁₈526.0026, found

526.0040.

Following the standard procedure for the preparation of

perﬂuoroalkenylzinc reagent, metallation of 1H,1H-perﬂuor-

ooctane (6.03 g, 15.0 mmol) with LDA (33.0 mmol) in

presence of ZnCl₂(2.04 g, 15.0 mmol) afforded

[C₆F₁₃CF CFZnCl] as a pink-brown solution in 79% yield

with E/Z ratio 98:2. ¹⁹F NMR (CDCl₃): [(E)-

C₆F₁₃CF CFZnCl]ÁTMEDA d À81.5 (t, J = 9.9 Hz, –CF₃),

À114.4 (m, CFCF₂), À122.4 (m, 2CF₂), À123.2 (m, –CF₂),

À126.5 (m, CF₂), À127.4 (s, CFZnCl), À144.6 (m, CF₂CF ).

3.6.4. (Z)-1-(4-Methoxyphenyl)perﬂuoro-1-octene

[4-MeOC₆H₄CF CFC₆F₁₃]

The perﬂuorooctenylzinc reagent solution [C₆F₁₃CF C

FZnCl] (2.7 mmol), 4-iodoanisol (0.370 g, 1.6 mmol) and

Pd(PPh₃)₄(0.030 g) were heated at 65 8C for 8 h. Trituration of

the reaction mixture with hexane followed by puriﬁcation of the

crude product by chromatography (eluent: 5% CH₂Cl₂–hexane)

afforded pure (Z)-1-(4-methoxyphenyl)perﬂuorooct-1-ene as a

colorless liquid in 87% (0.680 g, 1.4 mmol) yield. ¹⁹F NMR

(CDCl₃): d À81.3 (t, J = 10 Hz, 3F, CF₃–), À98.4 (d, J = 11 Hz,

1F, Ar-CF ), À113.5 (q, J = 13 Hz, 2F, CF₂–), À122.5 (m, 4F,

2CF₂–), À123.2 (m, 2F, CF₂–), À126.6 (m, 2F, CF₂–), À152.8

(m, 1F, R_F-CF ). ¹H NMR (CDCl₃): d 7.38 (d, J = 7.6 Hz, 2H),

6.93 (d, J = 8.6 Hz, 2H), 3.84 (s, 3H); GC/MS: 488 (M⁺, 14),

469 (67), 219 (100, BP), 199 (35), 69 (22); HRMS: calcd. for

C₁₅H₇F₁₅O 488.0257, found 488.0262.

3.6.1. (Z)-1-Phenylperﬂuorooct-1-ene

[C₆H₅CF CFC₆F₁₃]

The perﬂuorooctenylzinc reagent solution [C₆F₁₃CF C

FZnCl] (4.06 mmol), iodobenzene (0.579 g, 2.8 mmol) and

Pd(PPh₃)₄(0.056 g) were heated at 65 8C for 6 h. Trituration of

the reaction mixture with hexane followed by puriﬁcation of the

crude product by chromatography (eluent: hexane) afforded

pure (Z)-1-phenylperﬂuorooct-1-ene as a colorless liquid in

81% (1.05 g, 2.3 mmol) yield [42]. ¹⁹F NMR (CDCl₃): d À81.3

(t, J = 9 Hz, 3F, CF₃–), À99.9 (d, J = 9 Hz, 1F, Ar-CF ),

À113.7 (q, J = 12 Hz, 2F, CF₂–), À122.5 (m, 4F, 2CF₂–),

À123.3 (m, 2F, CF₂–), À126.6 (m, 2F, CF₂), À152.2 (m, 1F,

1

R_F-CF ). H NMR (CDCl₃): d 7.53–7.44 (m, 5H, ArH); GC/

MS: 458 (M⁺, 35), 439 (10), 200 (15), 190 (23), 189 (100, BP),

169 (92), 151 (17), 119 (17), 69 (28); HRMS: calcd. for

C₁₄H₅F₁₅458.0152, found 458.0156.

3.6.5. (Z)-1-(2-Methylphenyl)perﬂuorooct-1-ene

[2-MeC₆H₄CF CFC₆F₁₃]

The perﬂuorooctenylzinc reagent solution [C₆F₁₃CF C

FZnCl] (2.7 mmol), 2-iodotoluene (0.350 g, 1.6 mmol) and

Pd(PPh₃)₄(0.030 g) were heated at 65 8C for 18 h. Trituration

of the reaction mixture with hexane followed by puriﬁcation of

the crude product by chromatography (eluent: hexane)

produced the (Z)-1-(2-methylphenyl)perﬂuorooct-1-ene as a

colorless liquid in 78% (0.588 g, 1.3 mmol) yield. ¹⁹F NMR

(CDCl₃): d À81.3 (t, J = 10.8 Hz, 3F, CF₃–), À99.0 (d,

J = 12.3 Hz, 1F, Ar-CF ), À114.5 (q, J = 12.1 Hz, 2F, CF₂–),

À122.6 (m, 2F, CF₂–), À122.8 (m, 2F, CF₂–), À123.3 (m, 2F,

3.6.2. (Z)-1-(4-Fluorophenyl)perﬂuorooct-1-ene

[4-FC₆H₄CF CFC₆F₁₃]

The perﬂuorooctenylzinc reagent solution [C₆F₁₃CF C

FZnCl] (2.7 mmol), 4-ﬂuoroiodobenzene (0.360 g, 1.6 mmol)

and Pd(PPh₃)₄(0.030 g) were heated at 65 8C for 15 h.

Trituration of the reaction mixture with hexane followed by

puriﬁcation of the crude product by chromatography (eluent:

hexane) afforded pure (Z)-1-(4-ﬂuorophenyl)perﬂuorooct-1-

ene as a colorless liquid in 91% (0.692 g, 1.5 mmol) yield. ¹⁹

F

1

NMR (CDCl₃): d À81.3 (t, J = 10 Hz, 3F, CF₃–), À99.2 (dm,

not resolved, 1F, Ar-CF ), À107.4 (m, 1F, ArF–), À113.7 (q,

J = 13 Hz, 2F, CF₂–), À122.5 (m, 4F, 2CF₂–), À123.2 (m, 2F,

CF₂–), À126.6 (m, 2F, CF₂–), À152.2 (m, 1F, R_F-CF ). H

NMR (CDCl₃): d 7.42 (m, 1H), 7.29–7.20 (m, 3H), 2.38 (d,

J = 2.7 Hz); GC/MS: 472 (M⁺, 65), 453 (20), 204 (37), 203

(100, BP), 183 (78), 153 (45), 151 (67), 134 (60), 133 (86), 119

(27), 69 (65); HRMS: calcd. for C₁₅H₇F₁₅472.0308, found

472.0304.

1

CF₂–), À126.6 (m, 2F, CF₂–), À151.1 (m, 1F, R_F-CF ). H

NMR (CDCl₃): d 7.45 (dd, J = 7, 5 Hz, 2H), 7.14 (tm, J = 8 Hz,

2H); GC/MS: 476 (M⁺, 35), 457 (13), 207 (100, BP), 187 (88),

169 (23), 69 (38); HRMS: calcd. for C₁₃H₄F₁₄476.0058, found

476.0058.

3.7. Synthesis of the perﬂuorododecenylzinc reagent

[n-C₁₀F₂₁CF CFZnCl] and 1-arylperﬂuoro-1-dodecene

[n-C₁₀F₂₁CF CFAr]

3.6.3. (Z)-1-(3-Triﬂuoromethylphenyl)perﬂuorooct-1-ene

[3-CF₃C₆H₄CF CFC₆F₁₃]

The perﬂuorooctenylzinc reagent solution [C₆F₁₃CF C

Following the standard procedure for the preparation of

perﬂuoroalkenylzinc reagents, metallation of 1H,1H-perﬂuor-

ododecane (10.5 g, 17.0 mmol) with LDA (37.0 mmol) in

presence of ZnCl₂(2.3 g, 17.0 mmol) at 0 8C in THF-ether

medium (140 mL, 1:1) produced [C₁₀F₂₁CF CFZnCl] as a

brown solution in 61% yield.

FZnCl]

(2.7 mmol),

4-iodobenzotriﬂuoride

(0.440 g,

1.6 mmol) and Pd(PPh₃)₄(0.030 g) were heated at 65 8C for

10 h. Trituration with hexane followed by puriﬁcation of the

crude product by chromatography (eluent: hexane) afforded

pure (Z)-1-(3-triﬂuoromethylphenyl)perﬂuorooct-1-ene as a

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

469

3.7.1. (Z)- and (E)-1-phenylperﬂuorododec-1-ene

[C₆H₅CF CFC₁₀F₂₁]

Pd(PPh₃)₄(0.030 g) were heated at 65 8C for 10 h. Trituration

of the reaction mixture with hexane followed by puriﬁcation of

the crude product by chromatography (eluent: 5% CH₂Cl₂–

hexane) afforded a mixture of (E)- and (Z)-1-(4-methoxyphe-

nyl)perﬂuorododec-1-ene (Z/E 93:7) as a pale yellow waxy

solid in 76% (0.898 g, 0.914 mmol) yield. ¹⁹F NMR (CDCl₃): d

À81.3 (t, J = 11 Hz, 3F, CF₃–), À98.4 (d, J = 11 Hz, 1F, Ar-

CF ), À113.5 (q, J = 14 Hz, 2F, CF₂–), À122.2 (m, 12F,

2CF₂–), À123.5 (m, 2F, CF₂–), À126.6 (m, 2F, CF₂–), À152.9

(m, 1F, R_F-CF ). ¹H NMR (CDCl₃): d 7.38 (d, J = 8 Hz, 2H),

6.94 (d, J = 9 Hz, 2H), 3.58 (s, 3H); GC/MS: 688 (M⁺, 18), 669

(15), 219 (100, BP), 199 (27), 69 (26); HRMS: calcd. for

C₁₉H₇F₂₃O 688.0130, found 688.0132.

The perﬂuorododecenylzinc reagent solution [C₁₀F₂₁CF C

FZnCl] (2.09 mmol), iodobenzene (0.245 g, 1.2 mmol) and

Pd(PPh₃)₄(0.030 g) were heated at 65 8C for 12 h. Trituration

of the reaction mixture with hexane followed by puriﬁcation of

the crude product by chromatography (eluent: hexane) afforded

a mixture of (E)- and (Z)-1-phenylperﬂuorododec-1-ene (Z/E

94:6) as a colorless solid in 78% (0.616 g, 0.936 mmol) yield.

¹⁹F NMR (CDCl₃): d À81.2 (t, J = 10 Hz, 3F, CF₃–), À99.9 (d,

J = 8 Hz, 1F, Ar-CF ), À113.6 (m, 2F, CF₂–), À122.2 (m, 12F,

6CF₂–), À123.2 (m, 2F, CF₂–), À126.6 (m, 2F, CF₂–), À152.2

(m, 1F, R_F-CF ). ¹H NMR (CDCl₃): d 7.53–7.44 (m, 5H, ArH);

GC/MS: 658 (M⁺, 11), 639 (7), 189 (100, BP), 169 (75), 69

(27); HRMS: calcd. for C₁₈H₅F₂₃658.0024, found 658.0026.

3.8. Synthesis of (E)-1-iodoperﬂuoroalkenes

3.7.2. (Z)- and (E)-1-(3-

triﬂuoromethylphenyl)perﬂuorododec-1-ene

[3-CF₃C₆H₄CF CFC₁₀F₂₁]

3.8.1. (E)-1-Iodoperﬂuorohept-1-ene (C₅F₁₁CF CFI)

The perﬂuoroheptenylzinc reagent [C₅F₁₁CF CFZnCl] was

prepared at À78 8C by the metallation of 1H,1H-perﬂuor-

oheptane (3.05 g, 8.6 mmol) with LDA (18.9 mmol) in

presence of ZnCl₂(1.16 g, 8.6 mmol) as per the general

procedure. The reaction mixture was concentrated to half its

volume under vacuum and quenched with iodine (2.18 g,

8.6 mmol). Diethyl ether (50.0 mL) was added to the reaction

mixture and the organic layer washed with water (2Â 25 mL),

dried (anhy. Na₂SO₄) and the solvents were removed under

mild vacuum in a rotavaopur. The crude product was distilled

under reduced pressure to afford pure cis-1-iodoperﬂuorohept-

1-ene as a colorless liquid (2.69 g, 5.9 mmol, 68%) [bp: 50–

51 8C/20 mmHg]. ¹⁹F NMR (CDCl₃): d À81.3 (t, J = 11 Hz, 3F,

CF₃–), À82.3 (d, J = 9 Hz, 1F, I-CF ), À113.8 (m, 2F, CF₂–),

À123.1 (m, 2F, CF₂–), À123.4 (m, 2F, CF₂–), À126.7 (m, 2F,

CF₂–), À128.8 (m, 1F, R_F-CF ); HRMS: calcd. for C₇F₁₃I

457.8837, found 457.8837.

The perﬂuorododecenylzinc reagent solution [C₁₀F₂₁CF C

FZnCl] (2.09 mmol), 3-iodobenzotriﬂuoride (0.326 g,

1.2 mmol) and Pd(PPh₃)₄(0.030 g) were heated at 65 8C for

12 h. Trituration of the reaction mixture with hexane followed

by puriﬁcation of the crude product by chromatography (eluent:

hexane) afforded a mixture of (E)- and (Z)-1-(3-triﬂuoro-

methylphenyl)perﬂuorododec-1-ene (Z/E 93:8) as a colorless

waxy solid in 82% (0.713 g, 0.983 mmol) yield. ¹⁹F NMR

(CDCl₃): d À63.7 (s, 3F, Ar-CF₃), À81.4 (t, J = 11 Hz, 3F,

CF₃–), À102.0 (d, J = 7 Hz, 1F, Ar-CF ), À113.9 (m, 2F,

CF₂–), À122.3 (m, 12F, 6CF₂–), À123.4 (m, 2F, CF₂–),

1

À126.7 (m, 2F, CF₂–), À149.7 (m, 1F, R_F-CF ). H NMR

(CDCl₃): d 7.80 (d, J = 7 Hz, 1H), 7.72 (s, 1H), 7.64 (t,

distorted, 1H), 7.58 (d, distorted, 1H); GC/MS: 726 (M⁺, 3), 707

(3), 257 (100, BP), 237 (60), 187 (30), 169 (50), 119 (32), 69

(78); HRMS: calcd. for C₁₉H₄F₂₆725.9898, found 725.9894.

3.7.3. (Z)- and (E)-1-(3-ﬂuorophenyl)perﬂuorododec-1-ene

[3-FC₆H₄CF CFC₁₀F₂₁]

3.8.2. (E)-1-Iodoperﬂuorooct-1-ene (C₆F₁₃CF CFI)

The perﬂuorooctenylzinc reagent [C₆F₁₃CF CFZnCl] was

generated at À78 8C by the metallation of 1H,1H-perﬂuor-

ooctane (2.59 g, 6.5 mmol) with LDA (14.2 mmol) in presence

of ZnCl₂(0.878 g, 6.46 mmol) as per the general procedure.

Addition of iodine (1.64 g, 6.46 mmol) followed by work-up

and puriﬁcation by distillation afforded pure cis-1-iodoper-

ﬂuoroct-1-ene as a colorless liquid (2.30 g, 4.5 mmol, 70%)

[71] [bp: 67–70 8C/24 mmHg]. ¹⁹F NMR (CDCl₃): d À81.3 (t,

J = 11 Hz, 3F, CF₃–), À82.3 (d, J = 9 Hz, 1F, I-CF ), À113.7

(m, 2F, CF₂–), À122.2 (m, 2F, CF₂–), À122.8 (m, 2F, CF₂–),

À123.3 (m, 2F, CF₂–), À126.6 (m, 2F, CF₂–), À128.7 (m, 1F,

R_F-CF ); HRMS: calcd. for C₈F₁₅I 507.8805, found 507.8804.

The perﬂuorododecenylzinc reagent solution [C₁₀F₂₁CF C

FZnCl] (2.09 mmol), 3-ﬂuoroiodobenzene (0.266 g, 1.2 mmol)

andPd(PPh₃)₄(0.030 g)were heatedat65 8Cfor12 h.Trituration

of the reaction mixture with hexane followed by puriﬁcation of

the crude product by chromatography (eluent: hexane) afforded a

mixture of (E)- and (Z)-1-(3-ﬂuorophenyl)perﬂuorododec-1-ene

(Z/E92:8)asacolorlessviscousoilin72%(0.585 g,0.865 mmol)

yield. ¹⁹F NMR (CDCl₃): d À81.3 (t, J = 10 Hz, 3F, CF₃–),

À101.3 (d, J = 9 Hz, 1F, Ar-CF ), À111.9 (m, 1F, ArF–),

À113.9 (m, 2F, CF₂–), À122.3 (m, 12F, 6CF₂–), À123.2 (m, 2F,

1

CF₂–), À126.6 (m, 2F, CF₂–), À150.6 (m, 1F, R_F-CF ). H

NMR (CDCl₃): d 7.44 (m, 1H), 7.26–7.16 (m, 3H); GC/MS: 676

(M⁺, 7), 657 (5), 207 (100, BP), 187 (71), 169 (22), 69 (44);

HRMS: calcd. for C₁₈H₄F₂₄675.9930, found 675.9934.

References

[1] T. Hiyama, Organoﬂuorine Compounds: Chemistry and Applications,

Springer-Verlag, Berlin, 2000, pp. 183–233 [Chapter 6];

3.7.4. (Z)- and (E)-1-(4-methoxyphenyl)perﬂuorododec-1-

ene [4-MeOC₆H₄CF CFC₁₀F₂₁]

T. Hiyama, Organoﬂuorine Compounds: Chemistry and Applications,

Springer-Verlag, Berlin, 2000, pp. 137–177 [Chapter 5].

The perﬂuorododecenylzinc reagent solution [C₁₀F₂₁CF C

FZnCl] (2.09 mmol), 4-iodoanisole (0.281 g, 1.2 mmol) and

[2] R.E. Banks, B.E. Smart, J.C. Tatlow (Eds.), Organoﬂuorine Chemistry:

Principles and Commercial Applications, Plenum Press, New York, 1994.

470

A. Raghavanpillai, D.J. Burton / Journal of Fluorine Chemistry 127 (2006) 456–470

[37] R. Anilkumar, D.J. Burton, J. Fluorine Chem. 126 (2005) 455–461.

[3] W.W. Schmiegel, in: M. Hudlicky, A.E. Pavalath (Eds.), Organic Fluor-

opolymers in Chemistry of Organic Fluorine Compounds II: A Critical

Review, ACS Monograph, ACS, 1995, pp. 1101–1125.

[38] S. Dixon, J. Org. Chem. 21 (1956) 400–403.

[39] I.L. Knunyants, L.S. German, B.L. Dyatkin, Izv. Akad. Nauk. SSSR, Ser.

Khim. (1960) 221–230.

[4] D.J. Burton, Z.Y. Yang, W. Qiu, Chem. Rev. 96 (1996) 1641–1716, and

references cited therein.

[40] Yu.A. Fialkaov, L.M. Yagupolskii, Zhurn. Obshch. Khim. 36 (1966)

1968–1976.

[5] H.J. Tsai, A. Thenappan, D.J. Burton, J. Org. Chem. 59 (1994) 7085–7091.

[6] P. Martinet, R. Sauvetre, J.F. Normant, Bull. Soc. Chim. Fr. 127 (1990) 86–

92.

[41] W. Dmowski, J. Fluorine Chem. 18 (1981) 25–30.

[42] R. Albadri, P. Moreau, A. Commeyras, Nouveu J. Chim. 6 (1982) 581–

587.

[7] M.J. Tozer, T.F. Herpin, Tetrahedron 52 (1996) 8619–8683.

[8] J. Leroy, J. Org. Chem. 46 (1981) 206–209.

[43] P. Moreau, R. Albadri, A. Commeyras, Nouveu J. Chim. 1 (1977) 497–

502.

[9] F. Camps, J. Coll, G. Fabrias, A. Guerrero, Tetrahedron 40 (1984) 2871–

2878.

[44] W. Dmowski, J. Fluorine Chem. 15 (1980) 299–313.

[45] W. Dmowski, J. Fluorine Chem. 21 (1982) 201–219.

[46] W. Dmowski, J. Fluorine Chem. 26 (1984) 223–241.

[47] W. Dmowski, J. Fluorine Chem. 29 (1985) 273–286.

[48] W. Dmowski, J. Fluorine Chem. 29 (1985) 287–296.

[49] W. Dmowski, J. Fluorine Chem. 26 (1984) 379–394.

[50] W. Dmowski, Polish J. Chem. 60 (1986) 129–141.

[51] T. Nguyen, M. Rubienstein, C. Wakselman, J. Fluorine Chem. 11 (1978)

573–589.

[10] Y. Bessiere, D.H. Savary, M. Schlosser, Helv. Chim. Acta 60 (1977) 1739–

1747.

[11] J.R. McCarthy, D.P. Mathews, D.M. Stemerick, E.W. Huber, P. Bey, B.J.

Lipper, R.D. Snyder, P.S. Sunkara, J. Am. Chem. Soc. 113 (1991) 7439–

7440.

[12] D.P. Mathews, S.C. Millers, E.T. Jarvi, J.S. Sabol, J.R. McCarthy, Tetra-

hedron Lett. 34 (1993) 3057–3060.

[13] W.R. Moore, G.L. Schatzman, E.T. Jarvi, R.S. Gross, J.R. McCarthy, J.

Am. Chem. Soc. 114 (1992) 360–361.

[52] P.L. Heinze, D.J. Burton, J. Fluorine Chem. 31 (1986) 115–119.

[53] P.L. Heinze, D.J. Burton, J. Org. Chem. 53 (1988) 2714–2720.

[54] S.W. Hansen, D.T. Spawn, D.J. Burton, J. Fluorine Chem. 35 (1987) 415–

420.

[14] T. Allmendinger, Tetrahedron 47 (1991) 4905–4914.

[15] D. Ctemenceau, J. Cousseau, Tetrahedron Lett. 34 (1993) 6903–6906.

[16] V. Reutrackul, V. Rukachaisririkul, Tetrahedron Lett. 24 (1983) 725–728.

[17] S.T. Purrington, J.H. Pittman, Tetrahedron Lett. 28 (1987) 3901–3904.

[18] M.L. Boys, E.W. Colington, H. Finch, S. Swanson, J.F. Whitehead,

Tetrahedron Lett. 29 (1988) 3365–3368.

[55] M. Kuroboshi, T. Hiyama, Chem. Lett. (1990) 1607–1610.

[56] R. Anilkumar, D.J. Burton, Tetrahedron Lett. 44 (2003) 6661–6664.

[57] R. Anilkumar, D.J. Burton, J. Fluorine Chem. 126 (2005) 1174–

1184.

[19] T. Kawasaki, T. Ichige, T. Kitazume, J. Org. Chem. 63 (1998) 7525–7528.

[20] S. Hayashi, T. Nakai, N. Ishikawa, D.J. Burton, D.G. Naae, H.S. Kesling,

Chem. Lett. (1979) 983–986.

[58] D.J. Burton, T.D. Spawn, P.L. Heinze, A.R. Bailey, S. Shin-Ya, J. Fluorine

Chem. 44 (1989) 167–174.

[21] W.A. Vinson, K.S. Prikett, B. Spanic, P.R. Ortiz de Montellano, J. Org.

Chem. 48 (1983) 4661–4668.

[59] D.J. Burton, S. Shin-Ya, R.D. Howells, J. Am. Chem. Soc. 101 (1979)

3689–3690.

[22] T. Ishihara, M. Kuroboshi, Chem. Lett. (1987) 1145–1148.

[23] F. Tellier, R. Sauvetre, J.F. Normant, J. Organometall. Chem. 303 (1986)

309–315.

[60] D.J. Burton, D.G. Cox, J. Am. Chem. Soc. 105 (1983) 650–651.

[61] D.J. Burton, S. Shin-Ya, R.D. Howells, J. Fluorine Chem. 15 (1980) 543–

546.

[24] M. Kuroboshi, N. Yamada, Y. Takebe, T. Hiyama, Tetrahedron Lett. 36

(1995) 6271–6274.

[62] T.I. Filyakova, G.G. Belen’kii, E.P. Lur’e, A.Ya. Zapevalov, I.P. Kolenko,

L.S. German, Izv. Akad. Nauk. SSSR, Ser. Khim. (1979) 681–683.

[63] T.I. Filyakova, A.I. Zapevalov, M.I. Kodess, M.A. Kurykin, L.S. German,

Izv. Akad. Nauk. SSSR, Ser. Khim. (1994) 1614–1619.

[64] H.-J. Frohn, V.V.Z. Bardin, Anorg. Allg. Chem. 627 (2001) 2499–2505.

[65] H.-J. Frohn, V.V.Z. Bardin, J. Fluorine Chem. 123 (2004) 43–49.

[66] T. Mitsuru, N. Yoshitaka, F. Satoshi, JP 88-321935 (1990) (Chem. Abstr.

113: 190741).

[25] D.J. Burton, Z.Y. Yang, P.A. Morken, Tetrahedron 50 (1994) 2993–3063.

[26] L. Xue, L. Lu, S.D. Pederson, Q. Liu, R.M. Narske, D.J. Burton, J. Org.

Chem. 62 (1997) 1064–1071.

[27] C.R. Davis, D.J. Burton, J. Org. Chem. 62 (1997) 9217–9222.

[28] Q. Liu, D.J. Burton, Org. Lett. 4 (2002) 1483–1485.

[29] C. Lim, D.J. Burton, C.A. Wesolowski, J. Fluorine Chem. 119 (2003) 21–

26.

[67] K. Mikami, Y. Itoh, M. Yamanaka, Chem. Rev. 104 (2004) 1–16, and

references cited therein.

[30] J. Burdon, P.L. Coe, I.B. Haslock, R.L. Powell, Chem. Commun. (1996)

49–50.

[68] N.O. Brace, L.W. Marshall, C.J. Pinson, G. Wingerden, J. Org. Chem. 49

(1984) 2361–2368.

[31] J. Burdon, P.L. Coe, I.B. Haslock, R.L. Powell, J. Fluorine Chem. 99

(1999) 127–131.

[69] J.L. Hahnfeld, D.J. Burton, Tetrahedron Lett. (1975) 773–776.

[70] P.L. Heinze, T.D. Spawn, D.J. Burton, S. Shin-Ya, J. Fluorine Chem. 38

(1988) 131–134.

[32] R. Anilkumar, D.J. Burton, Tetrahedron Lett. 43 (2002) 2731–2733.

[33] A. Raghavanpillai, D.J. Burton, J. Org. Chem. 69 (2004) 7083–7091.

[34] R. Anilkumar, D.J. Burton, Tetrahedron Lett. 43 (2002) 6979–6982.

[35] R. Anilkumar, D.J. Burton, J. Fluorine Chem. 126 (2005) 833–841.

[36] R. Anilkumar, D.J. Burton, J. Fluorine Chem. 125 (2004) 561–566.

[71] R.D. Howells, H. Gilman, J. Fluorine Chem. 5 (1975) 99–114.

[72] N. Thoai, J. Fluorine Chem. 5 (1975) 115–125.

[73] D.R. Coulson, Inorg. Synth. 13 (1972) 121–124.

Article Doi

An efficient stereoselective preparation of cis-perfluoroalkenylzinc reagents [(E)-RFCF{double bond, long}CFZnCl] by the metallation of 1H,1H-perfluoroalkanes and their derivatization to cis-1-arylperfluoroalkenes [(Z)-RFCF{double bond, long}CFAr]

DOI: 10.1016/j.jfluchem.2005.12.022

Source and publish data:

Authors:

Article abstract of DOI:10.1016/j.jfluchem.2005.12.022

Full text of DOI:10.1016/j.jfluchem.2005.12.022

Products guided by the article

R&D Labs maybe for 924894-58-6

Relevant to this article

Hot Product