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Reaction of tributylphosphine (pentahaptocyclopentadienyl) copper (I) with iodoarenes
Tetrahedron Letters No.52, PP. 4585-4586, 1970.
Pergsmon Press.
Printed in Great Britain.
REACTION OF TRIBUTYLPHOSPHINE(PENTAHAPTOCYCLOPENTADIENYL) COPPER (I) WITH IODOARENES Martin Nilsson,
Robert Wahren and Olof Wennerstrijm
Department of Organic Chemistry,
Royal Institute of Technology,
S-100 44 Stockholm 70, Sweden in UC 5 October 1970;
(Received
Cyclopentadienylcopper
complexes
accepted for publication
with triphenyl-
and triethylphosphine
recently to be of the pentahapto type. 1,2 The present investigation whether a n-bonded
copper complex would react with iodoarenes
copper compounds like alkyl-
,
3
alkenyl- ,
4
alkynyl-
,
products.
Cyclopentadienylcopper suggested
by Cotton.
a suspension
@--
9
was undertaken to see in a way similar to
u-bonded
which react with halogenoarenes
to give
8
tributylphosphine
(lJ was prepared from cyclopentadienylthallium
as
An etheral solution of (CUIP(C~H~)~ )4 (2.5 mmole) was slowly added to
of cyclopentadienylthallium
CuPBus +
have been shown
’ phenyl- , ’ and 2-thienyl copper. 7 If so,
this would be in analogy with n-ally1 nickel complexes, unsymmetrical coupling
14 October 1970)
IoCH3 -
(10 mmole) in ether at O” x. Orange thallium (I) iodide
-
c&h
“3+ysFe
”
mCH3 x Reactions involving organometallic nitrogen.
H3
compounds were performed anhydrously under purified
4583
4504
No.52
precipitated
(99 %) . Stirring was continued for 10 minutes after the addition had been completed.
Cyclopentadienylcopper
tributylphosphine
is soluble in ether. The colourless
homogenous solu-
tion was withdrawn with a syringe for further reactions. Cyclopentadienylcopper
(approx.
10 mmole) was reacted with 4-iodotoluene
refluxing ether for 50 h. The reaction mixture was separated on a silica cyclopentadienyltoluene
gel column to give 4-
(50 %) and unreacted iodide (22 %).
The NMR spectrum (solvent CC14) showed a complex region between (relative area 4) and multiplets at r=6.70
(area 1) and
the methylenic protons in cyclopentadiene
have a T value of 7.00,
on the assumption that the coupling product consisted 4- (2,4-cyclopentadien-2-yl) QI
(10 mmole) in
toluene (2,
r=6.70)
re6.86
r =2.45 and 3.10
(area 1). In view of the fact that the NMR data were interpreted
of approximately equal amounts of
and 4-(2,4-cyclopentadien-3-yl)
toluene
1=6.86). Cyclopentadienylalkanes
3-cyclopentadienyl
are known to rearrange under mild conditions
isomers.
10
to mixtures of 2- and
The isolated coupling product was a strongly fluorescent
crystal mixture. After sublimation it gave a crystalline
mixture, m.p.
oil-
72 - 7E”, roughly con-
sistent with a 4 to 1 ratio of compounds 2 and 2, as seen by NMR spectroscopy. The mass spectrum (70 eV) showed the molecular ion at m/e = 156 (100 %). Methyl 2-iodobenzoate pentadienyl)
reacted with 1 for 24 h in refluxing ether to give
benzoate in 34 % yield (13 % unreacted iodide).
methyl 2-(cyclo-
The yield of coupling products was
unchanged when the thallium (I) iodide from the first reaction was not removed. nylthallium does not react with methyl 2-iodobenzcate
in refluxing ether.
The NMR spectrum (solvent CDC13) showed multiplets at rz6.70 (area 1) and two peaks at r=6.22 instrument).
In this case,
(combined
too, the isolated
Cyclopentadie-
(relative area 1) and 6.86
area 3) 0.7 Hz apart (measured with a 100 MHz product, a yellow fluorescent
hearly equal amounts of the 2- and 3-cyclopentadienyl
isomers.
liquid,
consisted
of
These could be separated on
GLC and had almost identical mass spectra. The mass spectrum (70 eV) showed the molecular ion at m/e = 200 (22 %) and the base peak at m/e = 168 (M-32). Both phenylcyclopentadienes corresponding
were easily hydrogenated with palladium on charcoal to the
phenylcyclopentanes.
4-(CYcloPentYl)
toluene gave an NMR spectrum (solvent CC14) with a single aromatic peak,
~0.52
4585
no ethylenic
protons,
and a broad methylene peak around T-8.3.
The mass spectrum (70 eV) showed the molecular ion at m/e = 160 (58 %) and the base peak at m/e = 131 (M-29). Methyl 2-(cyclopentyl) peak at
T=6.22,
benzoate gave an NMR spectrum (CC14) with a single methyl ester
no ethylenic
protons,
and a broad methylene peak around T=8.3.
The mass
spectrum (70 eV) showed the molecular ion at m/e = 204 (32 %) and the base peak at m/e = 144 (M-60). 1 , 1-Ditolylferrocene
iron (II) chloride
was obtained from the tolylcyclopentadiene,
(yield 21 %, m.p.
using butyllithium and
175-1794.
The NMR spectrum (solvent CC14) showed the ferrocene protons as multiplets at 5=5.59 and 5.84.
The mass spectrum (20 eV) gave the molecular ion at m/e = 366 (100 %). The second largest
peak was at m/e = 156 (3 %) , equivalent to ionised tolylcyclopentadiene. (KBr) was in accordance When kept at 4’
with that given by Nesmeyanov.
4-(cyclopentadienyl)
pentadienyl) benzoate
The infrared spectrum
11
toluene dimerises
in about a week, methyl 2-(cyclo-
in about a month. At room temperature both compounds polymerise irrever-
sibly in a few days. In n-cyclopentadienylcopper
phosphines,
and thus is not prone to coordinate phenylcopper reactions
the copper atom has 18 electrons
further. o-Bonded
can coordinate with other groups. 5,6
has been attributed to such coordinations.
in the reaction rate was only modemte, drastic example of the a-effect benzene and 2-iodobenzoic respectively.
compounds like ethynyl-
The ortho-effect
reported for copper-promoted
In this investigation
going from 4-iodotoluene
the increase
the mte constants
observed
to methyl 2-iodobenzoate.
is provided when copper (I) phenylacetylide
acid,
and
A
reacts with iodo-
being 8.0 x 10B6 and 7.0 x 10e2 1 mole-‘see
-1
5
Metal-halogen genoarenes.3’6
organocopper
in the outer shell
exchange has been reported for alkyl-
and arylcopper reactions
In the present case no biphenyls were observed,
with halo-
indicating that metal-halogen
exchange is of less importance. Phenylcyclopentadienes prepamtion of substituted
are of interest in connection ferrocenes.
The literature concerning
12
and the
13
cyclopentadienylarenes
prepared from bromoacetophenone
with organic dye lasers
is scarce.
and ethyl acetoacetate.
may prove to be a geneml route to these rather inaccessible
14
Phenylcyclopentadiene
Synthesis
has been
via cyclopentadienylcopper
and little studied compounds.
4586
No.52
Acknowledgements This work has been spectra
were recorded
supported
by The Swedish
by Mr Egon Pettersson.
of
Board
The English
Technical
Development.
was checked
by Patrick
The NMR Hort,
M.A.
References 1.
F.A.
Cotton
and J. Takats,
2.
L.T. J. Delbaere,
3.
E. J. Corey
4.
M. Nilsson
5.
C.E.
D.W.
and G.H.
McBride
Posner,
and R. Wahren,
Castro,
R. Havlin,
32, 2353 (1970).
J.Am.Chem.Soc.,
and R.B. Ferguson,
J.Am.Ohem.Soc.,
Acta Cryst.Sekt.B,
a,
Honwad,
Is,
A. Malte
515 (1970).
5615 (1968).
J.Organometal.Chem.,
V.K.
&
515 (1969) Mole,
and S.
J.Am.Chem.Soc.,
2,
6464 (1969). 6.
M. Nilsson
and 0. Wennerstim,
7.
M. Nilsson
and C. Ullenius,
8.
E. J. Corey and M.F.
9.
F.A.
Cotton
10.
V.A.
Mironov,
11.
A.N.
Nesmeyanov,
Acta Chem.Scand.,
Semmelhack,
and T. J. Marks, E.V.
Sobolev L.A.
In press.
a,
J.Am. Chem.Soc., and A.N.
Kazitsyna,
&&&, 1037 (1959).
12.
P.M.
Rentzepis
and M.A.
13.
D.E.
Bublitz
14.
R. Riemschneider
Duguay,
Rinehart,
and R. Nerin,
&,
J.Am.Chem.Soc.,
Nauk S.S.S.R.,
and K.L.
24, 482 (1970).
Acta Chem.Scand.,
7281 (1969).
Elizarova,
Tetrahedron,
B.V. Lokshin
and V.D.
Appl.
Q-g.
2755 (1967).
Phys.Letters,
React.,
Monatsh.Chem.,
a,
Q,
Vilchevskaia,
u,
218 (1967).
37 (1969). a,
829
1939 (1963).
(1960).
Doklady
Akad.
Pergsmon Press.
Printed in Great Britain.
REACTION OF TRIBUTYLPHOSPHINE(PENTAHAPTOCYCLOPENTADIENYL) COPPER (I) WITH IODOARENES Martin Nilsson,
Robert Wahren and Olof Wennerstrijm
Department of Organic Chemistry,
Royal Institute of Technology,
S-100 44 Stockholm 70, Sweden in UC 5 October 1970;
(Received
Cyclopentadienylcopper
complexes
accepted for publication
with triphenyl-
and triethylphosphine
recently to be of the pentahapto type. 1,2 The present investigation whether a n-bonded
copper complex would react with iodoarenes
copper compounds like alkyl-
,
3
alkenyl- ,
4
alkynyl-
,
products.
Cyclopentadienylcopper suggested
by Cotton.
a suspension
@--
9
was undertaken to see in a way similar to
u-bonded
which react with halogenoarenes
to give
8
tributylphosphine
(lJ was prepared from cyclopentadienylthallium
as
An etheral solution of (CUIP(C~H~)~ )4 (2.5 mmole) was slowly added to
of cyclopentadienylthallium
CuPBus +
have been shown
’ phenyl- , ’ and 2-thienyl copper. 7 If so,
this would be in analogy with n-ally1 nickel complexes, unsymmetrical coupling
14 October 1970)
IoCH3 -
(10 mmole) in ether at O” x. Orange thallium (I) iodide
-
c&h
“3+ysFe
”
mCH3 x Reactions involving organometallic nitrogen.
H3
compounds were performed anhydrously under purified
4583
4504
No.52
precipitated
(99 %) . Stirring was continued for 10 minutes after the addition had been completed.
Cyclopentadienylcopper
tributylphosphine
is soluble in ether. The colourless
homogenous solu-
tion was withdrawn with a syringe for further reactions. Cyclopentadienylcopper
(approx.
10 mmole) was reacted with 4-iodotoluene
refluxing ether for 50 h. The reaction mixture was separated on a silica cyclopentadienyltoluene
gel column to give 4-
(50 %) and unreacted iodide (22 %).
The NMR spectrum (solvent CC14) showed a complex region between (relative area 4) and multiplets at r=6.70
(area 1) and
the methylenic protons in cyclopentadiene
have a T value of 7.00,
on the assumption that the coupling product consisted 4- (2,4-cyclopentadien-2-yl) QI
(10 mmole) in
toluene (2,
r=6.70)
re6.86
r =2.45 and 3.10
(area 1). In view of the fact that the NMR data were interpreted
of approximately equal amounts of
and 4-(2,4-cyclopentadien-3-yl)
toluene
1=6.86). Cyclopentadienylalkanes
3-cyclopentadienyl
are known to rearrange under mild conditions
isomers.
10
to mixtures of 2- and
The isolated coupling product was a strongly fluorescent
crystal mixture. After sublimation it gave a crystalline
mixture, m.p.
oil-
72 - 7E”, roughly con-
sistent with a 4 to 1 ratio of compounds 2 and 2, as seen by NMR spectroscopy. The mass spectrum (70 eV) showed the molecular ion at m/e = 156 (100 %). Methyl 2-iodobenzoate pentadienyl)
reacted with 1 for 24 h in refluxing ether to give
benzoate in 34 % yield (13 % unreacted iodide).
methyl 2-(cyclo-
The yield of coupling products was
unchanged when the thallium (I) iodide from the first reaction was not removed. nylthallium does not react with methyl 2-iodobenzcate
in refluxing ether.
The NMR spectrum (solvent CDC13) showed multiplets at rz6.70 (area 1) and two peaks at r=6.22 instrument).
In this case,
(combined
too, the isolated
Cyclopentadie-
(relative area 1) and 6.86
area 3) 0.7 Hz apart (measured with a 100 MHz product, a yellow fluorescent
hearly equal amounts of the 2- and 3-cyclopentadienyl
isomers.
liquid,
consisted
of
These could be separated on
GLC and had almost identical mass spectra. The mass spectrum (70 eV) showed the molecular ion at m/e = 200 (22 %) and the base peak at m/e = 168 (M-32). Both phenylcyclopentadienes corresponding
were easily hydrogenated with palladium on charcoal to the
phenylcyclopentanes.
4-(CYcloPentYl)
toluene gave an NMR spectrum (solvent CC14) with a single aromatic peak,
~0.52
4585
no ethylenic
protons,
and a broad methylene peak around T-8.3.
The mass spectrum (70 eV) showed the molecular ion at m/e = 160 (58 %) and the base peak at m/e = 131 (M-29). Methyl 2-(cyclopentyl) peak at
T=6.22,
benzoate gave an NMR spectrum (CC14) with a single methyl ester
no ethylenic
protons,
and a broad methylene peak around T=8.3.
The mass
spectrum (70 eV) showed the molecular ion at m/e = 204 (32 %) and the base peak at m/e = 144 (M-60). 1 , 1-Ditolylferrocene
iron (II) chloride
was obtained from the tolylcyclopentadiene,
(yield 21 %, m.p.
using butyllithium and
175-1794.
The NMR spectrum (solvent CC14) showed the ferrocene protons as multiplets at 5=5.59 and 5.84.
The mass spectrum (20 eV) gave the molecular ion at m/e = 366 (100 %). The second largest
peak was at m/e = 156 (3 %) , equivalent to ionised tolylcyclopentadiene. (KBr) was in accordance When kept at 4’
with that given by Nesmeyanov.
4-(cyclopentadienyl)
pentadienyl) benzoate
The infrared spectrum
11
toluene dimerises
in about a week, methyl 2-(cyclo-
in about a month. At room temperature both compounds polymerise irrever-
sibly in a few days. In n-cyclopentadienylcopper
phosphines,
and thus is not prone to coordinate phenylcopper reactions
the copper atom has 18 electrons
further. o-Bonded
can coordinate with other groups. 5,6
has been attributed to such coordinations.
in the reaction rate was only modemte, drastic example of the a-effect benzene and 2-iodobenzoic respectively.
compounds like ethynyl-
The ortho-effect
reported for copper-promoted
In this investigation
going from 4-iodotoluene
the increase
the mte constants
observed
to methyl 2-iodobenzoate.
is provided when copper (I) phenylacetylide
acid,
and
A
reacts with iodo-
being 8.0 x 10B6 and 7.0 x 10e2 1 mole-‘see
-1
5
Metal-halogen genoarenes.3’6
organocopper
in the outer shell
exchange has been reported for alkyl-
and arylcopper reactions
In the present case no biphenyls were observed,
with halo-
indicating that metal-halogen
exchange is of less importance. Phenylcyclopentadienes prepamtion of substituted
are of interest in connection ferrocenes.
The literature concerning
12
and the
13
cyclopentadienylarenes
prepared from bromoacetophenone
with organic dye lasers
is scarce.
and ethyl acetoacetate.
may prove to be a geneml route to these rather inaccessible
14
Phenylcyclopentadiene
Synthesis
has been
via cyclopentadienylcopper
and little studied compounds.
4586
No.52
Acknowledgements This work has been spectra
were recorded
supported
by The Swedish
by Mr Egon Pettersson.
of
Board
The English
Technical
Development.
was checked
by Patrick
The NMR Hort,
M.A.
References 1.
F.A.
Cotton
and J. Takats,
2.
L.T. J. Delbaere,
3.
E. J. Corey
4.
M. Nilsson
5.
C.E.
D.W.
and G.H.
McBride
Posner,
and R. Wahren,
Castro,
R. Havlin,
32, 2353 (1970).
J.Am.Chem.Soc.,
and R.B. Ferguson,
J.Am.Ohem.Soc.,
Acta Cryst.Sekt.B,
a,
Honwad,
Is,
A. Malte
515 (1970).
5615 (1968).
J.Organometal.Chem.,
V.K.
&
515 (1969) Mole,
and S.
J.Am.Chem.Soc.,
2,
6464 (1969). 6.
M. Nilsson
and 0. Wennerstim,
7.
M. Nilsson
and C. Ullenius,
8.
E. J. Corey and M.F.
9.
F.A.
Cotton
10.
V.A.
Mironov,
11.
A.N.
Nesmeyanov,
Acta Chem.Scand.,
Semmelhack,
and T. J. Marks, E.V.
Sobolev L.A.
In press.
a,
J.Am. Chem.Soc., and A.N.
Kazitsyna,
&&&, 1037 (1959).
12.
P.M.
Rentzepis
and M.A.
13.
D.E.
Bublitz
14.
R. Riemschneider
Duguay,
Rinehart,
and R. Nerin,
&,
J.Am.Chem.Soc.,
Nauk S.S.S.R.,
and K.L.
24, 482 (1970).
Acta Chem.Scand.,
7281 (1969).
Elizarova,
Tetrahedron,
B.V. Lokshin
and V.D.
Appl.
Q-g.
2755 (1967).
Phys.Letters,
React.,
Monatsh.Chem.,
a,
Q,
Vilchevskaia,
u,
218 (1967).
37 (1969). a,
829
1939 (1963).
(1960).
Doklady
Akad.