Syntheses of (1,1-dihydroperfluoroalkyl)aryliodonium triflates and their analogues

of Fluorine Chemistr),,

Jounral

28 (1985)

235-239

235

Received: January15,1985;accepted: March 3, 1985

PRELIMINARY

NOTE

Syntheses

of

and Their

Analogues

Teruo

UMEMOTO*

Sagami

and Yoshihiko

Chemical

Kanagawa

Triflates

(l,l-Dihydroperfluoroalkyl)aryliodonium

229

Research

GOTOH

Center,

Nishi-Ohnuma

4-4-1,

Sagamihara,

(Japan)

SUMMARY

(l,l-Dihydroperfluoroalkyl)phenylnium

triflates

2 and 3 were

and -p-fluorophenyliodo-

synthesized

by the reaction

of

l-bis(trifluoroacetoxy)iodo-l,l-dihydroperfluoroalkanes triflic

acid

and benzene

trifluoroethane. acid

instead

1 with in 1,1,2-trichloro-

or fluorobenzene

The use of fluorosulfonic

of triflic

alkyl)phenyliodonium

acid

afforded

fluorosulfonate

acid

and sulfuric

(l,l-dihydroperfluoro4 and sulfate

2, respective.

Similarly, (l,l,w-trihydroperfluoroalkyl)phenyliodonium 1Y. triflate 7 and 1,1,5,5-tetrahydroperfluoropentane-l,5-bisphenyliodonium

triflate

9 were

synthesized.

INTRODUCTION

We have

already

nyliodonium that they ating

[lb,31 or novel

thesis

triflates

where

0022-l

The

stability

139/85/$3.30

of

(perfluoroalkyl)phe-

electrophilic

oxy-perfluoroalkylating

of

interest

of

and found

[1,21

perfluoroalkylagents

to study

[4].

In

the syn-

(l,l-dihydroperfluoroalkyl)aryliodo-

the trivalent

from the electronegative unit.

reactive

it is of great

and reactivity

a series

[l] and th eir analogues

triflates act as highly

this connection, nium

synthesized

iodine

perfluoroalkyl

atom

group

is separated by a methylene

(l,l,w-trihydroperfluoro-pentyl)-

or

0 Elsevier Sequoia/Printed in The Netherlands

236 -heptyl)-t_p-tolyliodonium

halides

rohexane-1,6-bis-p-tolyliodonium and only

the bromides

[5]. We have

were

succeeded

kyl)phenyliodonium

and

1,1,6,6-tetrahydroperfluo-

halides

isolated

in pure

shown

to be low

form in low yields

(1 ,I -dihydroperfluoroal-

in synthesizing

triflates

was

2 and their analogues

2, 4, 5_, 7,

and 9. RESULTS

AND DISCUSSION

l-Bis(trifluoroacetoxy)iodo-l,l-dihydroperfluoroalkanes were

prepared

quantitatively

perfluoroalkanes temperature

with

adding

acid

commercially anhydride

trifluoroacetic oration

available

to Yagupol'skii's

purification

[5]

in situ by -peroxide to trifluo-

of a catalytic

Alkanes

using a vacuum

further

procedure

prepared

60% hydrogen

at 0 OC.

of the solvent

acid at 0 'C to room

be smoothly

in the presence

acid

and used without

could

1 -

l-iodo-l,l-dihydro-

trifluoroperacetic

for 1 day,according

Trifluoroperacetic

roacetic

by treating

1 were pump

amount

isolated

of

by evap-

at room temperature,

for the next reaction.

TfOH >

RfCHz-:-OTf

PhH

Ph

1

2a 2b -

(Rf=CFj,

88%)

2c -

(Rf=n-C7F1s,

(Rf=n-C3F7,

70%) 89%)

Alkanes equiv.)

1 were allowed to react with benzene (1.2 molar and triflic acid (1 molar equiv.) in 1,1,2-trichloro-

trifluoroethane of the solvent an aspirator resulting

at 0 "C for 1 day. and

and

finally

crystals

form and collected. phenyliodonium

liberated

After

complete

trifluoroacetic

a vacuum

evaporation

acid using

pump without

heating,

first the

of the triflates A series

triflates

of

2&, 3,

2 were washed with chloro(l,l-dihydroperfluoroalkyl)-

and -2c were

synthesized

in

good yields. The use of fluorobenzene phenyliodonium

triflate

instead

of benzene

3 in a good yield. -

gave

p-fluoro-

237 TfOH 1 (Rf=CFa)

z

RfCH2-I-OTf

3

PhF 12%

F

Similarly, 1 reacted with benzene and fluorosulfonic acid to give the corresponding iodonium fluorosulfonate 4 in a high The reaction with benzene and sulfuric acid proceeded

yield.

smoothly using a mixture of 1,1,2-trichlorotrifluoroethane trifluoroacetic acid (9.6:l) as a solvent to afford the sulfate

FSO,H, PhH 1 (Rf=n-C7FlS)

)

RfCH,-I-OSO,F

95%

-4

;h

H,SO,, PhH 1

>

RfCH,-:-OSO,H

49%

(Rf=n-C,FIS)

5

Ph

l,l,w-Trihydroperfluoroalkyl analogue 7 was synthesized by the same method as for 2 except for the use of a mixture of 1,1,2-trichlorotrifluoroethane - trifluoroacetic acid (5:3) as a solvent. TfOH >

H(CF*) 1.CHzI(OCOCF3),

H(CE',),,CH,-:-OTf

PhH 6 -

Ph 7 -

85%

Furthermore, bisiodonium triflate 2 could be synthesized in a high yield by treating diiodide 8 with benzene (2.4 molar equiv.) and triflic acid (2 molar equiv.) in 1,1,2-trichlorotrifluoroethane at 0 OC for 4 days. TfOH, PhH (CF,C~~),ICH~(CF,)~CH~I(OCOCF,),

> 96%

8 TfO-I-CH,(CF,)JCH,-:-OTf Ah Ph 9 -

238 TABLE Some properties iodonium

Compound

of

triflates

a) M.p.

(“Cl 2a -

88-8gf (Decomp)

(l,l-dihydroperfluoroalkyl)aryland their

analogues

l H-Ii&UP) (6,

in CD3CN)

1~p_)JMRC)d) (in CD,CN)

4.8O(q, J=lOHz, 2H) 7.40-7.90(m, 3H) 8.00-8.30(m, 2H)

61.5(t, 77.9(s,

J=lOHz, 3F)

3F)

2b -

133 (Decomp)

4.80(t, J=lEHz, 2H) 7.60-7.95(m, 3H) 8.10-8.30(m, 2H)

78.1(s, 3F), 80.l(t, J=15 HZ, 3F), 104.4(m, 2F), 125.4(s, 2F)

2c -

142-143g (Decomp)

4.83(t, J=lEHz, 2H) 7.40-7.80(m, 3H) 8.05-8.25(m, 2H)

78.0(s, 3F), 80.6(s, 3F), 102.8(m, 2F), 120.8(m, EF), 124.9 (m, 2F)

3 -

103-104f (Decomp)

4.77(q, J=lOHz, 2H) 7.33(dd, J=9, 9Hz, 2H), 8.20(dd, J=9, 4.5Hz, 2H)

61.l(t, J=lOHz, 3F) 77.5(s, 3F), 102.8 (bs, IF)

4 -

107 (Decomp)

4.83(t, J=18Hz, 2H) 7.40-7.90(m, 3H) E-10-8.30(m, 2H)

-38.5(s, lF, S02F) 80.3(t, J=lOHz, 3F) 103.2(m, 2F), 120.8 (m, 6F), 122.0(m, 2F) 125.5(m, 2F)

5e -

90-91 (Decomp)

5.16(t, J=lEHz, 2H) 7.40-7.80(m, 3H) 8.20-8.40(m, 2H)

EO.O(t, J=lOHz, 3F) 120.5(m, 2F), 121,6 (m, 4F), 122.2(m, 2F) 122.8(m, 2F), 125.6 (m, 2F)

7 -

157-158

4.92(t, J=lEHz, 2H) 6.52(tt, J=51.0, 4.8Hz, lH), 7.5-8.32(m, 5H)

78.1(s, 3F), 103.1 (bs, 2F), 120.2-123.1 (m, 14F1, 128.7(bs, 2F), 137.8(d, J=51.0 Hz, 2F)

9

113-114 (Decomp)

4.80(t, J=lEHz, 4H) 7.40-7.90(m, 6H) 8.00-8.20(m, 4H)

78.0(s, 6F), 102.6 (m, 4F), 120.9(s, 2F)

a The elemental analyses of all the products were in good agreement with the calculated values. b Acetone-d6 was used for 5 as a solvent. c Chemical shifts are given in h ppm upfield from internal CFCl,. d Dimethyl sulfoxide-d, was used for 5 as a solvent. e Monohydrate. f Recrystallized from acetonitrile-diethyl ether at room temperature. g Recrystallized from hot acetonitrile.

239

Some properties triflates

of

and their

(l,l-dihydroperfluoroalkyl)aryliodonium

analoques

are shown

in the Table.

Thermolysis

of 2c at 140 - 145 "C produced l,l-dihydropertriflate and iodobenzene in high yields.

fluoroalkyl

n

2c -

>

RfCH,OTf

+

Phi 89%

90%

The reactivity trophilic

of these

triflates

as highly

l,l-dihydroperfluoroalkylating

reactive

agents

will

elec-

be report-

ed elsewhere.

ACKNOWLEDGEMENT

The authors Sawahata

wish

to express

for her experimental

their

thanks

to Miss Miwa

assistance.

REFERENCES

1

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