The stereospecific preparation of F-alkenyl cadmium reagents directly from F-alkenyl iodides and bromides and cadmium metal

Journal of Fluorine Chemistry. 31

461

( 1986) 46 l-465

Received: February 25, 1986;accepted: March IO, 1986

PRELIMINARY

Ihe

NOTE

Sterwific

E-W

Prep-

E-&nvl

Iodides and5

DONALD

J. BURTON*

Department

and

Cw

Dfrectlv

and Cadmium

STEVEN

of Chemistry,

Frpm

+

W. HANSEN

Unfversfty

of

Iowa,

Iowa

City,

Iowa

52242

(U.S.A.)

SUMMARY

E-Alkenyl reactfon room

cadmium

of E-alkenyl

temperature

configuration. wfth

to 60°C.

control.

fs excellent,

(via distfllatfon)

stable

synthetic

The

synthetic has been

organometallic

be readfly

reactions

proceed

thermal

The

reagent

alkenyl

analogs,

Consequently, E-vinyl

utility

+Presented Chemfstryr 0022-I

solvate.

Current

vinyl

proceed

was fsolated

procedure

a

to these

organometalllc

coupltng

G.D.R.,

of

only

some success

except for recent reports

zfnc reagents

thus far, have received

compounds

has therefore

reagents, and recent reports

However,

of E-vinyl

Grignard

of these

applications

[3,41 have demonstrated

reagents.

our attention

and vfnyl

stability

laboratory

and synthetic

C5r6,71r the E-

limited attentfon.

has focused on a general

route to stable

that would satisfy the following

in part at the 11th International

139/86/$3.50

also

of

of the cadmium

lithium

thermal

work in our

Cl,21 and others

East Berlin,

at

retention

This approach provides

one-pot

of fluorfnated

fluorinated

organometallfc

total

processes

direct

in DMF

reagents.

and/or E-aryl

with Pd" catalyzed

via the powder

(Z-CF3CF=CF)2Cd

impeded by the restrfcted

from our laboratory with E-alkyl

with

stability

up, stereospecific,

compounds.

stable

cadmium

functionalitatfon

been directed toward the preparatfon thermally

prepared

with

as a DMF or trfglyme

scaled

alkenyl

can

or bromides

and the U

facile, easily

reagents

The

and subsequent

stereochemical

reagents

reagents lodides

August

Symposium

1985, Abstracts

on Fluorine B-4

0 ElsevierSequoia/Printed in The Netherlands

462 criteria:

(1) the

temperature

or above,

pregeneration minimal

so that

experimental

formation

integrity

synthetic

transformations

formation

of these

accessible

so that

initial

focus

reagents.

reagents

obtained.

via

+

only

2 Cu

vinyl

prerequisite

Thus, studies.

hallde

would

Analogous

active

that

and

(4)

(or one-pot)

with

from

of the

and that

alkenyl

reactlon

of E-vinyl

iodides

to

cadmium

react

HBS

the

reagents

organometallic

vinyl

criteria,

precursor.

initial

stability

and

model

and the

would

assist

of E-aryl

X = I, Br

+

gave

"ICd

in mono cadmium

no bfphenyl

no and

allow

us to

or bis reagents

(coupled)

report

herein

reagents

that

can

these

be easily

lodides

or bromides

readily

(short

1n DMF

lnductlon

expectations

were

prepared

direct

under

period)

via

mild

Cd a-> RT-60°C

RFCF=CFCdX

+

(RFCF=CF)2Cd

realized

conditions.

The

at room temperature,

DMF R$F=CFX

an

of an noted

compound

metal,

with

Consequently,

Additionally,

reagent

and cadmium

rapidly

halide

for our

formation

copper was

2 CuI

diene.

exhibited

halides.

in the

reacts

met the previously with

copper

diene)

the selection

in the organometallic

Also,

E-vinylic

Cll.

observed pleased

+

of E-alkenyl

and activated

intermediate

analogs

vinyl

preparation

(symmetrical

symmetrical

couple

hydrocarbon

bromopentafluorobenzene was

the

not only

readily

assignments.

We are

copper

to give

isotopes

formation

structural

vinyl

organocadmium

of coupling

NMR

vinyl

step

halides

product

in our approach

not

we selected

indication

product

(or

in preparative

to pregenerate

CF2=CF-CF=CF2

compound

that

attempts

direct

of f-vinylic

_3

additional

from

of these

materials;

in a one

on the

the coupled the

additional

organometallic

all

reaction

Apparently,

2 CF2=CFI

monitor

in control

functionalization

polyfunctionalized

concentrated

However8

directly

unsuccessful;

'13Cd

(2)

be retained

stereochemical

be utilized

be achievable

with

apparatus;

elaboration

possess

could

up and

precursors.

Our

one

must

to yield

reagents

should

so that

scaled

be accomplished

glassware

in further

they

at room

be readily

LL-precursors reagent,

stability

could

in standard

reagents

capability,

but

with

could

compound

be accomplished

(3) the

intermediates;

thermal

reactions

difficulty

exchange)

were

possess

of the organometallic

potentially

copper

must

of the organometallic

stereochemical

could

reagents

+

CdX2

463

and the vinyl

bromides

require mild

were formed as a mono/his the vinylic

However,

halide.

of reaction was detected summarizes

TABLE

mixture

heating

(6OOC).

no significant

difference

in functionalization

these preliminary

The cadmium

reagents

and this ratio varied with Structure in mono/his

of these reagents.

of

rates

Table

I

results.

I

Preparation

of Alkenyl

Cadmium

Reagents

from E-Vinyl

Halides

and Cadmium

DMF RFCF=CFX

+

Cd ____)

RFCF=CFCdX

+

(RFCF=CF)ZCd

+

CdXZ

RT-60°C

Olefin

YielcP

CFZ=CFI

CFZ=CFCdX

99

Z-CF3CF=CFI

Z-'CF3CF=CFCdX

96

E-CF3CF=CFI

f-CF3CF=CFCdX

92

Z-CF3KFZ)&F=CFI

Z-CF3(CF2)&F=CFCdX

95

CF3CF=CICF3'

CF3CF=C(CF3)CdXd

91

CF3CF=C(Ph)CF=CFBre

CF3CF=C(Ph)CF=CFCdXf

61

&CF3C(Ph)=CFI

E-CF3C(Ph)=CFCdX

77

a

of mono and bfs reagent; X = halogen

Mixture

or another f-alkenyl

group. b

"F

'

E/Z mixture;

NMR yield a.

d

E/Z = 37/63

e

E,Z:Z,Z

= 90/10

f

E,Z:Z,Z

= go/10

The reactions determined

proceed with total

from "F

lgF NMR analysis thermal

PhCF3.

E/Z = 39/61

stability

retention

NMR or '13 Cd NMR analysis

of the resultant

hydrolysis

of these organometallfc

solution

of Z-CF3CF=CFCdX

activity

in one dayt lZ% activity

of configuration,

of the cadmium

compound

product, RFCF=CFH.

compounds

as

is remarkable.

in dry DMF at room temperature

or

The A

lost only 3%

in 8 days , and 15% activity

in 35 days.

464 Even

at 123'C

a short-path

this

solution

distillation

recrystallization

from

(Z-CF3CF=CF)2Cd.DMF mixture

lost

25%

from CH2Clg/pentane

(1:7) gave

(Z-CF3CF=CF)2Cd*TG,

mp 64-65'C

in 1.5 hours.

mixture

(1:51 gave

mp 77-80°C.

followed

activity

a reaction

CH2C12/pentane

solvate,

fromtrfglyme,

only

of such

followed

white

an analogous with

the

crystals

Distillation

of the

by recrystallfzatfon

of the reaction

of the distillate

triglyme

following

Indeed.

by

solvater

spectroscopic

properties:

a c

"F

cFx

JFb

F

$

,c=c

NMR

'13Cd

2

(CDC13)

NMR

Cd TG * :

a

-67.2

ppm

(dd)

J

=

22.3

Hz

b

-145.8

ppm

(ddq)

J ac =

12.8

Hz

C

-177.5

ppm

(dq)

= 103.8

Hz

:

236.4

ppm

(tt)"

"'Cd

= 306

Hz

'13Cd

= 320

Hz

(CDC13)

Jbc Jbr

Jb' J

All

the cadmium

rapidly

hydrolyzed

(Et0)2PC1, acid

and PhgCl

anhydrides,

instead

gave

The lined

however,

operational

moisture

the a,@

of a typlcal

acyl

are

halides

-unsaturated

or

ketone;

but

reaction.

experimental

of Z-CF3CF=CFCdX

and

CH2=CHCH2Br,

with

partfcfpiitfon

a Solvent

= 48 Hz

sensitive wfth

Acylation

to give

via

details

111Cd,113Cd

C#

Functionalization readily.

failed

preparation

procedure

are out-

from Z-l-iodo-E-propene

and

powder.

A two-necked, septum

port,

source

was

and 11 ml

50 ml,

magnetic

charged

To

with

this

extreme

high

'13Cd-CF3,

the

mixture

reaction

bottom

bar,

mixture

cadmium

apparatus was

added

was

the

However

with

J = 4 Hz,

is normally

fitted

with

connected powder

maintained

thermometer, to

until

the

spectrum

appears

normal

resolution

not observed.

a nitrogen

(1.70 grams, under

Z-1-iodo-E-propene

stirred

resolution

of septets.

flask

and condenser

acid-washed

and

The

triplets

round

stir

of dry DMF.

atmosphere. mmoles).

*Under

are extremely

occurred

(CH3)2NCH(RF)2

for the

cadmium

reagents to RFCF=CFH.

ab

mfld

15 mmoles)

a nitrogen (3.1 grams, exotherm

as a triplet the coupling

12

sub-

of of

465 sided

and the

cadmium

was

reaction "F

NMR

mixture

removed

mixture

of the

exhibits

were

a fine

of the

resultant

carried

23

out

at

utllizing

In conclusionr of E-alkenyl compounds

cadmium

adequately

stable-alkenyl extensive for the

synthesis) Interesting

these

organometallic

We wish

metathesis and

funnel).

"F

Functionalization

yield,

stereospecific

(YI.

NMR

(bd.m)Fb;

Hz.

high

These

designed

chemistry

organometallic

(DMF)

-177.8

ppm

reactions

organometallic

for the

future

as well

compounds

processes.

Our

reports

preparation

preparation

of

will

find

as applicability

(not available

work

will

they

continues

detail

via

to explore

applications

of

reagents.

the

Foundation

Air

Force

for

1 P.L.

Heinze

and D.3.

Burton,

2

D.J.

Burton

and

D.M.

Wiemers,

3

L.J.

Krause

and

J.A.

Morrison,

4 H. Lange

ppm

excess of the

yield

reagents , and we anticipate

in preparative

to thank

Science

102

is described.

reagents

(Schlenk a 96%

= 67/33);

-141.5

criteria

via

these

(mono/his

reagents

of other

filter

the

nitrogen)

solution.

mild,

the

Then,

dry

indicated

meet

utilization

National

this

(under

glass

(dd)CF3;

12 Hz; Jbc

organometallic

synthesis

direct

ppm

a simple,

temperature.

solution

reagent

-65.9

Hz; J,,

room

fritted

Z-CF3aCFC=CFbCdX

resonances

(bd.dq) Fc; Jab

to

filtration

through

analysis

PhCF3)

had cooled by pressure

and D. Naumann,

Office

support

of Scientific

of our

J. Fluorine J. Am.

Chem.,

Chem.

J. Chem.

2e

Sot.,

Sot.

J.FluorineChem.,

Research

and the

work.

Chem. z

(1985)

359.

J.QZ (1985) Commun.,

(1984)

5014. (1980)

671.

1; 21i (1984)

93. 5 P.L. 6

Heinze Gillet,

J.P.

and

D.J.

Burton,

R. Sauvetre,

and

J. Fluorine

J.F.

Chem.,

Normant,

a

(1986)

Tetrahedron

115.

Letters,

(1985)

3999. 7

F. Tellier, 292

(1985)

R. Sauvetre, 19.

and

J.F.

Normant,

J. Organometallic

Chemistry,