Fluoro-ketones IV. Synthesis of phenylperfluoroalkyl ketones - mechanism of reaction between phenyllithium and fluoroesters

117

Joumalof Fluorine Chemistry, 18 (1981) 117-129 0 Elsevier Sequoia S.A., Lausanne Received:

November

24, 1980

FLUORO-KETONES SYNTHESIS

IV.

OF PHENYLPERFLUOROALKYL

OF REACTION

LOOMIS

~ Printed in The Netherlands

BETWEEN

S. CHEN**,

PHENYLLITHIUM

Patterson

- MECHANISM

AND FLUOROESTERS*

GRACE J. CHEN**

Air Force Wright Aeronautical Wright

KETONES

and CHRIST

Laboratories,

Air Force Base, Ohio

TAMBORSKI

Materials

45433

Laboratory,

(U.S.A.)

SUMMARY Although

fluorine

fluoroalkyl) reagents

have been prepared

and perfluoroalkyl

applicability.

Variable

and tertiary

alcohol

We have examined addition

lent yields hemiketal

from the reaction

by-products

By controlling compounds

of the ketone.

stability

which

of secondary

been experienced.

influence

experimental

can be attained.

conditions

excel-

salt of a

intermediate

in

of the salt and its potential

the type of reaction

of the lithium

are produced

mode of

ketone product

A lithium

and shown to be the active

The stability

with the solvent dictates favors

organolithium

and co-production

ester structure

formation.

between

Rf = per-

has not found general

the factors e.g., temperature,

(II) has been isolated

temperature

the reaction

have in most instances

in more detail

high yields of ketones

(RfC(O)Rf and RfC(0)R,

yields of ketones

of C6H5C(0)Rf

the production

ketones

esters,

and perfluoroalkyl

and by-products

reaction

containing

products.

salt of the hemiketal

LOW whereby

on hydrolysis.

INTRODUCTION Organometallic fluorocarbon reagents

with

fluorocarbon ondary

compounds

ketones

[1,21.

fluorocarbon ketones

and tertiary

have been extensively

used in the synthesis

The reactions

Grignard

between

esters have been previously

in variable

yields

of

or organolithium

reported

along with by-products

to yield e.g., sec-

alcohols.

*Presented at the Second Chemical Congress of the North American Continent, 25-29 August 1980, Las Vegas, Nevada, Division of Fluorine Chemistry, paper number 3. **University of Dayton Research Institute, Dayton, Ohio 45469 (U.S.A.)

118 H

0

0 +

R'Li

+

R$R’

&

H

9 RfCR’

+

R,;R/

A

For example, reaction

in earlier

between

in yields alcohol,

studies McBee,

n-C3F,Li

ranging

alcohol,

(n-C3F7)3COH,

studies

on the reaction

0% to 44%. ported.

The presence

and Levine

tertiary

studies

ture, time and mode of addition

[41 the reactions of providing

fluorocarbon

yields

(Rf)3COH, yields

alcohols,

alcohols,

experimental

[4] in their e.g., CF3C02CH3, ranging

from 18%

ranging

(RfC~(0~)C6H5)

conditions

from

was not re-

of reaction

tempera-

were varied.

studies we have reexamined

In our current

objective

RfC(0)C6H5,

the

(n-C3F,)2C=0

of the tertiary

and a series of esters

of the secondary

In both previous

reported

McGrath

C6H5Li

reported

of the secondary

Formation

and n-C3F.,C02CH3 noted ketone,

to 64% and the by-product

formation

from 0% to 42%.

was not observed. between

[31

and Curtis

to yield the ketone

from 0% to 33% with by-product

ranging

(~-c~F~)~CH(OH),

C2F5C02CH3

Roberts

and n-C3F7C02C2H5

(1)

R’

in more detail

than previously

C6H5Li and perfluorocarbon

between

and general

an improved

synthesis

esters with the

procedure

for per-

ketones.

DISCUSSION With hydrocarbon

compounds,

RLi and an acyl derivative to the reactions

shown in Scheme

The final products

related

to the thermal

X (acid halides), In our present (in Scheme

are a function

lithium

stability

studies on reaction

Y can be H (aldehydes),

salt I.

an organolithium [51 to proceed

reagent, according

of ease of expulsion

The group Y leaving

of the lithium

of organolithium

R (ketones), OLi

OC(O)R

between

1.

of the reaction

group Y from the intermediate

ported

the reaction

RC(O)Y has been suggested

salt I.

compounds

In the various

study we have examined

is

re-

with acyl derivatives,

(from acids), NR2

(acid anhydrides)

of

capacity

(secondary

amides),

or OR (esters). thus far the following

1) where Y is -0CH 3 and -OC2H5,

R'Li is CSH5Li

variations

and R is CF3,

n-C F i-C3F7, n-C3F,0[CF(CF3)CF,01nCF(CF3) and%2FSO(CF2CF20),CF2. C2F5‘ 3 I' The reactions were carried out under various experimental conditions of time, temperature, a summation mentioned

mode of addition of the reaction

experimental

and variation

products

conditions.

of ester structure.

found based on variations

Table 1 is of the above

119

t

+

RCY

Y=H =R = OLi = NR2

R'Li

6x3 Li 00 h'P R-C-Y R'

=x = OC(O)R = OR

I H 0

0

I

-HY

II

R-C-Y

l

"-:: R'

A-

+ R'Li 1 H

Li

P R-C-R'

P R-7-R'

H308 f

ASCHEME

R' 1

On the assumption that the reaction between C6H5Li and a perfluorocarbon ester yields

an intermediate

where Y=OR) a similar reaction

products

lithium

and expanded

of Table

salt of a hemiketal

suggested

mechanism

1 is shown in Scheme

II,

R,&

the

2.

H 0

0

(see Scheme

explaining

0

+ Rf-d-g

Rf-l-@

+ LiOR

4

?

A I

/

B

0 Rf-:-OR

SCHEME

+ @Li

---+

2 Lithium Salt of a Hmiketal II

Fi ----+ C

RfLi

+ @-C-OR

1

ADDED

1

5

4

3

2

1

EXPERIMENT

C6H5Li

TABLE

MIN

MIN

-4O'/lO MIN 4 RT/5 DAYS

n-C3F7

MIN

-78O/lO

-40"/10 MIN 4 RT/6 DAYS

-78O/lO

RT/lO MIN c RT/8 DAYS

-40'/10 MIN J RT/4 DAYS

-78O/lO

TEMP/TIMEa

n-C3F7

'ZF5

C2F5

CF3

CF3

CF3

Rf

TO ESTER

0 3

82 79

0

86.5

98

1

88

87

0.5

0.5

87

0.5

0.5

2

96

98

0

0

;

R$-@

H 0

98

98

R&

0

13

1.5

12

11.5

1.5

18

18

2

2

2

;

13

R&i

H 0 &OCH,

0 FF R;OC=CF

OTHERSC

a b c d

C2F50(CF2CF20)3CF2

3

17

55

in reaction temperature. was made to determine yield.

18

27

6

0.5

96 76

2

99

0°/30 MIN 4 RT/26 HRS J RT/6 DAYS 4 RT/12 DAYS

5

1

b

90d

5

5

99

b

36d

59

b

Id

3.5

0

brd

0

0

b

99

99

btd

0

0

‘7f“‘lo MIN

-30"/30 MIN J. 0"/30 MIN J RT/24 HRS

-7r’10M=N

89

TRACE

The Vindicates the reaction was allowed to increase Products were identified by GC/MS and IR, no attempt Minor products were not characterized completely. C6H5CO;C2H5

11

C3F7GEF

F

MIN

-llO'/lO

i-C3F7

9

10

MIN

-78'/10

i-C3F7

8

122 The stability

of the lithium

factor in determining pendently

synthesize

success.

The addition

and n-C3F7C02CH3

products

of C6H5Li

produced

II seems to be the major

to be formed.

II and thus prove its existence

however

to inde-

CF3C02CH3,

Isolation

II at -78'C.

was successful

Attempts

met with partial

to a series of esters,

the proposed

salt II at room temperature of the series

salt of a hemiketal

the reaction

C2F5C02CHJ

of pure lithium

only with the first member

(R~=cF~).

Li 0

RfLAOCH3 + C6H5Li

(2)

E Rf,0CH3

+

'gH5

__ During

the attempted

room temperature, n-C3F7

member.

nitrogen)

The relative

the following

on heating

stable

(under

to 15O'C to produce

of each of the above lithium

of the intermediate

salt of hemiketals

conclusions

have been reached

II governs

the subsequent

1, 2 and the synthesis

From the data in Tables

exception

(C6-5Li added to RfE2R_'of the i-C3F, derivative

hemiketals

(II) are stable.

high yields

in regard

for-

of II,

to the various

temperature formation

experi-

substituted

of the secondary

formation

of II to secondary

products

II is unstable

CF3CF=CF2

substituted

alcohol

and C6H5C02C2H5

The C3F70CF(CF3)

increases

(Exp. 8).

substituted

at a much faster the rate of trans-

(Exp. 2,5,7).

The i-C3F7

to yield as the final

At -llO"C,

however,

the

stable such that on acid hydrolysis

substituted

(EXP. 101, begins

to decompose

i-C3F,

to yield n-C3F70CF=CF2

derivative

alcohols

group increases

at -78OC and decomposes

II is sufficiently

hours does the

The C2F5 and n-C3F7

at -1lO'C an 89% yield of ketone was obtained C6H5C02C2H5.

for at least 24 hours at room

yield secondary

As the length of the perfluoroalkyl

substituted

above -78'C the CF3 and

II are stable

alcohol begin.

salt of

at -78OC they all produce

Only after many additional

to room temperature

(-78'C) with the

(Exp. 8 and 9), all the lithium

At temperatures

(Exp. 1 and 11) _

II on warming

at low temperature

On acid hydrolysis

of the ketones.

C2F50(CF2CF20)3CF2

i-C3F7

was thermally

however,

conditions:

Temperature

rate.

II at

the ketones.

stability

of products.

substituted

at a slower rate than the

and decomposed

Acid hydrolysis

(II) at -78'C produced

mental

of the C2F5 and n-C3F7 decomposed

The CF3 derivative,

at room temperature

C6H5C(0)CF3.

mation

isolation

the C2F5 member

in addition

II, which

to CF3CF=CF 2 and

is stable at -78OC

above -3O'C by the same mechanism and C6H5C02C2H5.

as the

123 Li

0 RftOR

+

RfLi

+

LiF

+

C6H5C02R

(3)

R;CF = CF2

(4)

I 'gH5 RfLi where

R

f

Rf Mode of Addition -78'C between

= i-C3F7;

the ester and C6H5Li

are present

is fast, the mode of addition

to the ester,

Conversely

by adding

the stability

salts of the hemiketals

ferent rates, where

the reaction

ester.

These observations the reaction

alcohols

suggest

in excess

that the lithium

Li 0

I 'gH5

decompose

the at dif-

This was

of reaction

the reaction

during the addition of the reaction are produced

of the

(EXP. 13,15, in 98% yield.

salts of the hemiketals with the ketone

were

(II) in

and CH30Li,

e.g.

0

I RfCOCH3

temperature,

at -40°C to yield the ketones

RfC(OH) (C6H5)2 which

medium must be in equilibrium

are present

At -4O'C,

is CF3> C2F5> n-C3F,.

mixtures

the major products

At room temperature,

17) are the tertiary

is very

the reaction

the reaction

of II varies.

RfC(OH) (C6H5)2 which were formed through

of the ketone with the C6H5Li present

at

From the data in Table 2,addition

The other major products

in 96%, 53% and 37% respectively. alcohols,

products

the ester to C6H5Li

(II) (EXP. 12,14,16)

the order of stability

by hydrolyzing

the tertiary

the reaction

in the excess C6H5Li.

-4O'C, and room temperature,

determined

= n-C3F70

it can be seen that by varying

of ester to C6H5Li,

three lithium

“;

(RfCO,CH3 added to C6_HsLi)- Since the rate of reaction

in the excess ester. products

R; = CF3

= n-C3F70CF(CF3);

By adding C6H5Li

important.

+

II -

-4

+

RfC

CH30Li

I

'sH5

1

C6H5Li

Li 0

(5)

124 TABLE

2

ESTER

ADDED

H 0

TO C6H5Li 0

EXPERIMENT

TEMP/TIMEa

Rf

12

14

15

4

94

2

4

1

1

98

53

1

46

4

49

47

0

2

98

37

0.5

62.5

RT/6 DAYS

0

37.5

62.5

RT/lO

0

MIN

MIN

-40'/10 1

n-C3F7

17

0

RT/lO

C2F5

16

96

-40"/10 MIN 1 RT/3 DAYS

C2F5

n-C3F7

MIN

MIN

aThe 4 indicates the reaction reaction temperature. As the ketone RfC(OLi)

after hydrolysis

data at -40°C and room temperature the equilibrium

stability librium

to the right by reacting

of the lithium

concentration,

yields

with

98

to increase

by addition

0C2H5 derivative

the equilibrium

of C6H5Li

to the esters

by addition

differently

which

effects

of C6H5Li

shifts

The

their equi-

and is in identical

salts of the hemiketals RfC02CH3.

From the

concentration

RfC(OLi) (C6H5j2.

is CF3> C2F5> n-C F 37 attempts.

isolation

is prepared

salt formed behaves

of the excess C6H5Li

salt of the hemiketals

therefore,

in

and forms the

the RfC(OH) (C6H5j2.

product

of the -OR Group - The above lithium

prepared

allowed

the presence

to form the non-equilibrium

order to their observed Nature

was

2

is formed it reacts with the C6H5Li present

(C6H5j2 which

of RfC(0)C6H5

+ er

RT/lO

CF3

R&-@ ;I

-40"/10 MIN I RT/3 DAYS

CF3

13

R&

H 0

If, however,

to CF3C02C2H5

which were the

the lithium

than the OCH 3 analog. Li

?I C6H5Li

+

CF3W2H5

‘: -

CF3y2H5 'gH5 III

(6)

125 When

III is prepared

ketone CF3C

CF,C(O)C,H5

at -40°C and acid hydrolyzed

is formed

If the reaction

(OH) (C6H5)2 is also formed.

to warm to room temperature creases

with time

ary alcohol

This observation

and acid hydrolyzed,

(27h, 18%) with the concurrent

CF3C(OH)H

at this temperature

mixture

is contrary

to the -CCH3

is then allowed

the percent formation

(27h, 61%) and other products

C6H5

the

in 99% yield and less than 1% of the alcohol

derivative

ketone

de-

of the second-

in minor quantities.

of II which

is stable

up to 15ooc. The secondary well understood

alcohol

formation

as shown by route A, Scheme

at this time and requires

further

ever, not only in the case of the lithium as the main decomposition

product

salt of the hemiketal

at higher

2 is not

It is noted,

study.

temperatures

how-

III but also

of the II where

and n-C3F7 and as minor decomposition products where Rf = CF3 Rf = C2F5, Although other investigators [3,6,71 have previously and C2F50(CF2CF20)3CF2. noted the secondary ation covering

alcohol

formation,

a satisfactory

all type of Rf and OR substituents

mechanistic

interpret-

has not been established

as yet. Nature

of the Rf_ - From the above,

II is CF3> C2F50(CF2CF20)3CF2> The thermal

stability

It does not appear

ketals

factors

Electronic

must be a more important

consideration.

could not be conveniently

studied

carbonyl

group increase

correlation stretching the highest

between

salt of the hemi-

spectroscopically

at room tempera-

frequencies carbonyl

were investigated

on the C=O frequency

frequencies

provide

the most

provide

to the

There is a close

frequency[8].

order of stability

frequencies

was deter-

groups adjacent

of II and the carbonyl The ketones

of their ketone precursors.

with the lowest carbonyl

by infrared

3.

electronegative

its vibrational

the observed

reason

therefore

Since the lithium

RfC(0)C6H5

are shown in Table

It is well known that highly

of the Rf substituent.

of the Rf substituent

The effect of the Rf substituent

mined and the results

stabilizes

i-C3F7.

alone could be the principal

effects

ture, the stable ketone precursors analysis.

C3F70CF(CF3)>

of the II must be a function

that steric

(see EXP. 5 vs. 111.

the nature of the Rf group which

C2F5>n-C3F7>

exhibiting

stable II while

the least stable

the ketones

II.

CONCLUSION The reaction through

between

a transient

is sufficiently

C6H5Li

lithium

stable

and various

esters

salt of the hemiketal

(the exception

RfC02R appear (II).

is the i-C3F7

to proceed

At -78'C,

substituted

the II

II where

126 TABLE

3

Rf STRETCHING

B C

FREQUENCY

(cm

-1

0

) in RfC C H

6 5

CF3

1724.1

C2F50(CF2CF20)3CF2

1725.4

C2F5

1709.4

n-C3F7

1711.1,

C3F70CF(CF3)

1711.9

i-C3F7

1700.9,

-1lO'C

is required)

such that acid hydrolysis

duces high yields of the ketones -78OC,

the stability

temperature

whereby

a variety

at least three different hemiketal

(II).

temperatures

of the secondary

1724.1

(minor)

temperature

prothan

on the nature of Rf, OR, and

may be obtained

modes of decomposition

Formation

and longer reaction

the available

depending

of products

(minor)

at the low temperature At higher

C6HSC(O)Rf.

of II varies

1716.3

resulting

of the lithium

salt of a

alcohol C6H5C(OH)HRf

times has not been

from

at higher

rationalized

from

data.

EXPERIMENTAL

General

Comments

All reactions

were carried

phere of dry nitrogen. [4,9,10,111

out in anhydrous

Most isolated

and have been characterized

(with known compounds).

Compounds

CF3C(OLi). (CCH3)C6H5

however,

ysis and separation

(for analytical

10% SE-30 on chromosorb

l/8" x 6' SE-30 chromosorb Digilab analyses

FTS-ZOC

W column.

spectometer

were performed

on an XL-100

TMS and CFC13 as internal

were performed

standards.

were

for chemical IR analyses

in Ccl4 solution

i-C3F7C(OlC6HS

GC anal-

on a l/4' x 6',

carried

ionization,

out on a using a

were performed

or as neat samples.

spectometer

time

and

(see experimental).

GC/MS analyses

modified

reported

IR and GC retention

n-C3F7C(OH)HC6H5,

purposes)

and under an atmos-

have been previously

by GC/MS,

are new compounds

W column.

du Pont 490 mass spectometer

solvents

compounds

on N.M.R.

using CDC13 solvent

and

Synthesis

of CF3C(OLi) (ocH~)c~H~(~.c.)

Into 25Oml three-necked magnetic

stirrer

anhydrous

diethyl

4.47mmol)

and CF3C02CH3

anhydrous

diethyl

above rapidly

ether

(90ml), n-octane

2O.Ormml)

ether,

stirred

temperature

by GC.

solution

an aliquot

Phenyllithium

The solution

sample removed,

mixture

stirring

decomposed

at -40°c

with 2~ HCl

to warm to room

for 7 days during which

and analyzed

plus a white

weight was determined

and washed

on heating

(42%) of product.

to CF~C(O)C~H~

hydrolyzed

for 7 days, a white

It was filtered

mixture.

1.89

of 30 min to the

by GC.

The

1 (EXP. 1).

at room temperature

from the reaction ether to yield

0_51g,

was stirred

was then allowed

samples were removed periodically

a

were placed

(19.4ml of 1.03M in

added over a period

at -4OOC.

The reaction

results were given in Table

molecular

was

thermometer,

atmosphere,

(internal GC standard,

and then stirred at room temperature

time aliquot

While

under a nitrogen

(2.56g, 2O.Omm01).

for an additional lOmin, and analyzed

flask with a low temperature

and maintained

with anhydrous

diethyl

the solid to Q15O'C

solid suspected

by acid-base

solid precipitated

titration

it

to be CH30Li.

Its

(neutral equivalent);

Found, M.W. 212+ - 1, Calc'd, 212. Analysis: Calc'd for C9H8F30Li; C, 50.96%; H, 3.77%; Li, 3.27%; Found: c, 50.72%; H, 3.55% and Li, 3.2%. On acid hydrolysis

Addition

the solid produced

of C6H5Li

to RfC(0)OCH3

These experiments above.

Results

an internal

Addition

were performed

from periodic

standard

of C6H5Li

8.31mmol) trolled

HCl

to the one described

and GC analysis

using

1.

flask fitted with a low temperature

buret was added anhydrous

and phenyllithium

was added over a period

so as to keep the reaction

the reaction

manner

samples

are listed in Table

(2.Olg. 8.31mmol).

liquid N2 bath)

of aliquot

to i-C3F,C(0)OC2H5(-110°C)

and an addition

i-C3F7C02C2H5

in an identical

removal

(n-octane)

Into a 250ml three-necked stirrer

CF3C(0)C6H5.

for 30 min at -llO°C,

(2ml) and methanol

The contents

diethyl

were cooled

(8.37ml of 0.993M

thermometer, (100ml) and

to -1lO'C

in anhydrous

temperature

of -110°C.

After

(2r60°C) solution

(EtOH-

diethyl

The rate of addition

of 12 min.

a cooled

ether

stirring

of cont.

(Sml) was slowly added in order to hydrolyze

ether

was con-

the

128 reaction

indicated

C6HgC02C2H5

M.W.

was then poured GC analysis

and dried over MgS04.

(n-octane)

1.42g

The mixture

mixture.

separated

Distillation

b.p. 76-78°c/15mm;

(mass spectral)

calc'd

2CF3) and -179.1

Analysis:

calc'd

Addition

274, found 274; NMR(ppm):

(multiplet

for C10H5F70;

of C,H,Li

Phenyllithium

moved,

(multiplet).

After

bath).

solution

with

an additional

During

and analyzed

(doublet,

ether,

27.9mmol)

of C3F70CF(CF3)C(0)OC2H5 ether at -78OC

by GC.

(Dry Ice-

sample was re-

The reaction

mixture

for 30 min and then to R.T. aliquot

temperatures,

samples were removed

See Table 1 (Exp. 10).

of n-C3F7C(OH)HC6H5(n.c.)

the synthesis

alcohol

was prepared

of CF3C(OLi)(OCH3)C6H5

2O.Ommol)

and phenyllithium

2O.Ommol)

were used and the reaction

the reaction

mixture

5 days during which During

G.C. analysis

after

and a concurrent

as an internal 3.6g

indicated increase

a gradual

to stir an additional and analyzed

decrease

in the secondary

(mass spectral)

Distillation Analysis:

calc'd.

of the

alcohol

a 91% yield of the secondary

G.C. standard).

ether;

After warming

out at -78'C.

it was allowed

for

(4.56g;

diethyl

samples were removed

(65%), b.p. 42"C/O.O3mm.

(OH at 3620.6 cm-l); M.W.

as described

that n-C3F7C02CH3

was carried

aliquot

5 days indicated

(using n-octane

for C10H,F70:

except

to room temperature, time periodic

mixture

yielded

in the same manner

(19.4ml of 1.03M in anhydrous

this time the analysis

ketonen-C3F7C(0)C6H5

calc'd

(multiplet,

- 2.3Hz, CF);

10 min, an aliquot

2N WC1 and analyzed

these various

by CC.

The secondary

by GC.

diethyl

diethyl

for 30 min. then to O°C over 30 min period

Synthesis

H, Q8.0 F, -73.8

to warm up to -3OOC over 18 min and kept at this temperature

was allowed

for 24 h.

yielded

1724.1 cm -11;

to C,F,OCF(CF,)C(O)OC,H,

in 400ml of anhydrous

hydrolyzed

of

C, 43.81; H, 1.84; found: C, 43.72; H, 1.68.

(27.9ml of l.OOM in anhydrous

(lO.Og, 27.9mmol)

phase

standard

mixture

- septet - 7Hz, triplet

was added over 12 min to a precooled

isopropanol

of the reaction

IR (c=o at 1700.9,

2_3Hz, ortho H split by ZCF), and Q7.5 7.OHZ,

@OOml),

in 89% yield and smaller quantities

i-C,F,C(O)C,H5

and CF3CF=CF2.

(65% yield),

into 2M HCl

using an internal

alcohol

of the reaction

infrared

data

276; found 276; Analysis:

C, 43.49; H, 2.55; found: C, 43.2; H, 2.29.

129 Addition

of R,C(O)OCH3

C3F7C02CH3 ether

to rapidly

2O.Ommol)

isopropanol an aliquot

dissolved

bath).

The solution

of anhydrous

was stirred

was added over a

ether cooled

to -40°C

(Dry Ice-

at -40°C for an additional

and analyzed

to warm to room temperature,

by G.C.

diethyl

(19.4ml of 1.03M in diethyl

diethyl

hydrolyzed

for 6 days during which

cally and analyzed

in mixture

(internal GC standard,O.SOg)

removed,

ture was then allowed

-4O'C to R.T.)

stirred phenyllithium

in 70ml of anhydrous

sample

temperature

(RF="-C3F7;

(4.56g, 2O.Ommol),

(20ml) and n-octane

30 min period ether,

to C6H5Li

time aliquot

by G.C.

5 rain,

The reaction

and then stirred

mix-

at room

samples were removed

periodi-

See Table 2.

ACKNOWLEDGEMENTS We would

like to thank James E. Schwarberg

for performing

the infrared

of the Materials

and Dr. Chi-Kuen

analyses

Laboratory

Yu for mass spec-

tral analyses.

REFERENCES 1

W. A. Sheppard and C. M. Sharts, Benjamin Inc., New York, 1969

2

M. Hudlicky, 'Chemistry New York, 1976

3

E. T. McBee, C. W. Roberts 6387

4

T. F. McGrath

5

B. J. Wakefield, 1976, pg. 136

of Organic

R.N.

E. T. McBee, (1952) 1736

8

R. E. Kagarise,

9

H. Gopal, E. J. Soloski

Haszeldine,

H. Gopal and C. Tamborski,

11

K. C. Eapen and C. Tamborski,

Halsted

Press,

J. Am. Chem. Sot., -77 C1955)

Press, New York,

J. Am. Chem.

Sot., -74

Sot., -77 (1955) 1377

and C. Tamborski,

10

W. A.

(1748)

and J. F. Higgins,

3. Am. Chem.

Compounds',

Compounds I, Pergamon

J. Chem. Sot., 1953

0. R. Pierce

Chemistry',

J. Am. Chem. Sot., -77 (1955) 3656

'Organolithium

7

Fluorine

and S. G. Curtis,

and R. Levine,

6

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J. Fluorine

J. Fluorine

Chem.,

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Chem., -13 (1979) 337

J. Fluorine

Chem., -14 (1979) 243