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A new and efficient reaction for the synthesis of the carbon-carbon bond
Tetrahedron Printed in
Letters,Vol.29,No.29,pp Great Britain
A NEW AND EFFICIENT
3533-3536,1988
REACTION
FOR THE SYNTHESIS
0040-4039/88 $3.00 Pergamon Press plc
+ -00
OF THE CARBON-CARBON
BOND
Derek H. R. Barton, Nubar Ozbalik and Manian Ramesh
Department
of Chemistry, Texas A&M University College Station, Texas 77843
Summary. Palladium (0) converts tellurides of type R’-Te-R* into coupled product R’-R* and metallic tellurium (as a mirror) in high yield under mild conditions. There is little or no sign of p-elimination and no evidence for cross coupling.
We recently compounds
and metallic
a-P-phenylunexpected
reported
ethylbismuth
that palladium
bismuth
(0) converts
aryl derivatives
in high yield under mild conditions. ’
of Bi(II1) and Bi(V) to diary1
More interesting
1 afforded the coupled product 2 (74%) at room temperature.
was the fact that This coupling was
as Pd(I1) species such as 3 are supposed to 8- eliminate and not give ligand coupling.*
The product
of the reaction should have been styrene.3 We decided to examine the effect of Pd(0) on symmetrical noted that diary1 tellurides colleague@
treated with degassed
studied the arylation
of olefins
moderate yield in the absence of the olefin. vinyl-tellurium
compounds
and unsymmetrical
tellurides.4
Raney nickel gave diaryls in good yield.
using Te(IV) compounds
and W(B).
Bergman5
Uemura and his
Diaryls were formed in
Finally, Uemura’ has also examined the carbonylation
of aryl- and
under the influence of Pd(I1) species; Te(0) and Pd(0) are also formed.
not found any record of a potentially
p- eliminatable
We have
alkyl residue (with transfer from tellurium) being used in
Pd(0) coupling. Nevertheless
a series of tellurides,
including
(Table) using Pd(0) generated from Pd(OAc), of 8-elimination;
four with alkyl residues,
and triethylamine.
there was no scrambling of ligands.
3533
have been smoothyl
coupled
In only one case was there some indication
3534
Reaction Entry
a) b) cl d)
Substrate
Solvent
Time
Yield Productb
7c
1
4
CH,CN
8h
6
100
2
5
HMPA
7hC
6
82
3
z
CH,CN
10h
2
8Sd
4
s
CH,CN
5h
9
81
5
lo
CH,CN
7h
11
89
6
12
CH,CN
7h
13
76
All reactions performed with Pd(0) catalyst, prepared in from Pd(OAc), (1 mmole) and NEt, (2 mmole), and the telluride (1 mmole) at 65” under argon atmosphere. All compounds were characterised by m.p. (where appropriate), N.M.R. and Mass Soectrometrv. An additional eiuivalent of Pd(0) catalyst was added 3 hrs. after the commencement of the reaction. Some styrene was also formed. (PhCH,CH,)sBi
(PhCH,CH,),
1 An,Te
2 (AnTe);?
4 PhCH,CH,TeCH,Ph s An-t-Ad 11
2
AnAn 5
5
(PhCH,CH,),Pd
Ph(CH,),Ph 9 An-Te-CtsHs,
(PhCH,CH,),Te z An-Te-I-Ad lo
An-ClsH3t
3535
Whilst 4 gave dianisyl 6 in quantitative was a good yield obtained.
yield, the ditelluride
4 gave the coupled
product
ligand as well as a stronger phenyl-tellurium total product
showed
Only in HMPA
The telluride 1 gave the same coupled product 2 (85%) as had been obtained before
from the bismuth derivative _l_.There was some p-elimination The telluride
was much less reactive.
no sign of dianisyl,
2 (81%).
bond.
to give styrene. The telluride
JtJ contained
Again the yield was good (89%) and g.c. analysis of the
the likely product of scrambling.
reaction mixture did not show any scrambled
a weak t-adamantyl
product either.
The mass spectrum
of the total
Finally telluride 12 gave the coupled product 12
without p-elimination. The tellurides
used in this work were prepared
by standard
methods.4
The two tellurides
a
and 121
method already reported. 8 This works well with diary1 ditellurides,
were obtained using the photochemical
but
is less efficient with dialkyl ditellurides. It is relevant
to our present
findings
diethylpalladium(I1)
without additive
olefins
acrylate
like methyl
Although
gave, as expected,
afforded
bonding of some kind is responsible
R’ ‘Ted
However,
addition
of certain
It is clear that palladium-tellurium
G-butane with no p-elimination.
to give an exact mechanism
for our new reaction, the Scheme outlines
The other ligands involved remain to be determined.
R’ ‘,Te+
Pd (II)
RY
+
ethane and ethylene.
of (2,2’-bipyridine)
for the success of our coupling reactions.
it would be premature
a suitable working hypothesis.
that recent work9 has shown that pyrolysis
R’ Pd (0)
>Te= Pd(ll)
M
R*
R2
Te=Pd,
P’2
+
Te (0)
+
Pd (0)
+
R’-R*
R
Scheme This coupling reaction should be useful in the chemistry
Acknowledgements. support of this work.
We thank the Welch Foundation
of Natural Products.
and the Schering-Plough
Corporation
for their generous
3536
References
1.
D.H.R. Barton, N. Ozbalik and M. Ramesh, Tetrahedron,
2.
T. Hosokawa and P.M. Maitlis, J. Am. Chem. Sot., z, 4924 (1973); D.J. Mabbot and P.M. Maims, 1, Organomet. Chem., 102, C34 (1975); G.M. Whitesides, Pure and Appl. Chem., 53, 287 (1981): A. Yamamoto, T. Yamamoto, S. Komiya and F. Ozawa, ibid. 56, 1621 (1984).
3.
R.H. Crabtree, “The Organometallic Chemistry of the Transition York, 1988; R.F. Heck, “Palladium Reagents in Organic Syntheses”,
4.
K.J. Irgolic, “The Organic Chemistry York, 1974.
5.
J.Bergman, Tetrahedron, 2, 3323 (1972); see also L. Engman, Act. Chem. Res., g, Clive, P.C. Anderson, N. Moss and A. Singh, J. Org. Chem., 47, 1641 (1982).
6.
S. Uemura, M. Wakasugi and M. Okano, J. Organomet.
7.
S. Uemura, K. Oke, J.-R. Kim, K. Kudo and N. Sugita, J. Chem. Sot. Chem. Commun., Oke, H. Takahashi, S. Uemura and N. Sugita, J- Organomet. Chem., 326, 3.5 (1987); m, 2,4859 (1987).
8.
D.H.R. Barton, D. Bridon and S.Z. Zard, Heterocycles,
9.
R. Sustmann and J. Lau, Chem. Ber., 119, 2531 (1986); Tetrahedron Letts. Yamamoto, A. Yamamoto and S. Ikeda, J. Am. Chem. Sot., 93, 3350 (lm’
(Received
in
USA 26 April
of Tellurium”,
1988)
in press.
Metals”, John Wiley and Sons, New Academic Press, New York, 1985.
Gordon and Breach Science
Chem., 194,277
Publishers
Inc., New
274 (1985); D.L.J.
(1980). 271 (1985); K. J. Org. Chem.,
25,449 (1987).
26, 4907 (1985); see also T.
Letters,Vol.29,No.29,pp Great Britain
A NEW AND EFFICIENT
3533-3536,1988
REACTION
FOR THE SYNTHESIS
0040-4039/88 $3.00 Pergamon Press plc
+ -00
OF THE CARBON-CARBON
BOND
Derek H. R. Barton, Nubar Ozbalik and Manian Ramesh
Department
of Chemistry, Texas A&M University College Station, Texas 77843
Summary. Palladium (0) converts tellurides of type R’-Te-R* into coupled product R’-R* and metallic tellurium (as a mirror) in high yield under mild conditions. There is little or no sign of p-elimination and no evidence for cross coupling.
We recently compounds
and metallic
a-P-phenylunexpected
reported
ethylbismuth
that palladium
bismuth
(0) converts
aryl derivatives
in high yield under mild conditions. ’
of Bi(II1) and Bi(V) to diary1
More interesting
1 afforded the coupled product 2 (74%) at room temperature.
was the fact that This coupling was
as Pd(I1) species such as 3 are supposed to 8- eliminate and not give ligand coupling.*
The product
of the reaction should have been styrene.3 We decided to examine the effect of Pd(0) on symmetrical noted that diary1 tellurides colleague@
treated with degassed
studied the arylation
of olefins
moderate yield in the absence of the olefin. vinyl-tellurium
compounds
and unsymmetrical
tellurides.4
Raney nickel gave diaryls in good yield.
using Te(IV) compounds
and W(B).
Bergman5
Uemura and his
Diaryls were formed in
Finally, Uemura’ has also examined the carbonylation
of aryl- and
under the influence of Pd(I1) species; Te(0) and Pd(0) are also formed.
not found any record of a potentially
p- eliminatable
We have
alkyl residue (with transfer from tellurium) being used in
Pd(0) coupling. Nevertheless
a series of tellurides,
including
(Table) using Pd(0) generated from Pd(OAc), of 8-elimination;
four with alkyl residues,
and triethylamine.
there was no scrambling of ligands.
3533
have been smoothyl
coupled
In only one case was there some indication
3534
Reaction Entry
a) b) cl d)
Substrate
Solvent
Time
Yield Productb
7c
1
4
CH,CN
8h
6
100
2
5
HMPA
7hC
6
82
3
z
CH,CN
10h
2
8Sd
4
s
CH,CN
5h
9
81
5
lo
CH,CN
7h
11
89
6
12
CH,CN
7h
13
76
All reactions performed with Pd(0) catalyst, prepared in from Pd(OAc), (1 mmole) and NEt, (2 mmole), and the telluride (1 mmole) at 65” under argon atmosphere. All compounds were characterised by m.p. (where appropriate), N.M.R. and Mass Soectrometrv. An additional eiuivalent of Pd(0) catalyst was added 3 hrs. after the commencement of the reaction. Some styrene was also formed. (PhCH,CH,)sBi
(PhCH,CH,),
1 An,Te
2 (AnTe);?
4 PhCH,CH,TeCH,Ph s An-t-Ad 11
2
AnAn 5
5
(PhCH,CH,),Pd
Ph(CH,),Ph 9 An-Te-CtsHs,
(PhCH,CH,),Te z An-Te-I-Ad lo
An-ClsH3t
3535
Whilst 4 gave dianisyl 6 in quantitative was a good yield obtained.
yield, the ditelluride
4 gave the coupled
product
ligand as well as a stronger phenyl-tellurium total product
showed
Only in HMPA
The telluride 1 gave the same coupled product 2 (85%) as had been obtained before
from the bismuth derivative _l_.There was some p-elimination The telluride
was much less reactive.
no sign of dianisyl,
2 (81%).
bond.
to give styrene. The telluride
JtJ contained
Again the yield was good (89%) and g.c. analysis of the
the likely product of scrambling.
reaction mixture did not show any scrambled
a weak t-adamantyl
product either.
The mass spectrum
of the total
Finally telluride 12 gave the coupled product 12
without p-elimination. The tellurides
used in this work were prepared
by standard
methods.4
The two tellurides
a
and 121
method already reported. 8 This works well with diary1 ditellurides,
were obtained using the photochemical
but
is less efficient with dialkyl ditellurides. It is relevant
to our present
findings
diethylpalladium(I1)
without additive
olefins
acrylate
like methyl
Although
gave, as expected,
afforded
bonding of some kind is responsible
R’ ‘Ted
However,
addition
of certain
It is clear that palladium-tellurium
G-butane with no p-elimination.
to give an exact mechanism
for our new reaction, the Scheme outlines
The other ligands involved remain to be determined.
R’ ‘,Te+
Pd (II)
RY
+
ethane and ethylene.
of (2,2’-bipyridine)
for the success of our coupling reactions.
it would be premature
a suitable working hypothesis.
that recent work9 has shown that pyrolysis
R’ Pd (0)
>Te= Pd(ll)
M
R*
R2
Te=Pd,
P’2
+
Te (0)
+
Pd (0)
+
R’-R*
R
Scheme This coupling reaction should be useful in the chemistry
Acknowledgements. support of this work.
We thank the Welch Foundation
of Natural Products.
and the Schering-Plough
Corporation
for their generous
3536
References
1.
D.H.R. Barton, N. Ozbalik and M. Ramesh, Tetrahedron,
2.
T. Hosokawa and P.M. Maitlis, J. Am. Chem. Sot., z, 4924 (1973); D.J. Mabbot and P.M. Maims, 1, Organomet. Chem., 102, C34 (1975); G.M. Whitesides, Pure and Appl. Chem., 53, 287 (1981): A. Yamamoto, T. Yamamoto, S. Komiya and F. Ozawa, ibid. 56, 1621 (1984).
3.
R.H. Crabtree, “The Organometallic Chemistry of the Transition York, 1988; R.F. Heck, “Palladium Reagents in Organic Syntheses”,
4.
K.J. Irgolic, “The Organic Chemistry York, 1974.
5.
J.Bergman, Tetrahedron, 2, 3323 (1972); see also L. Engman, Act. Chem. Res., g, Clive, P.C. Anderson, N. Moss and A. Singh, J. Org. Chem., 47, 1641 (1982).
6.
S. Uemura, M. Wakasugi and M. Okano, J. Organomet.
7.
S. Uemura, K. Oke, J.-R. Kim, K. Kudo and N. Sugita, J. Chem. Sot. Chem. Commun., Oke, H. Takahashi, S. Uemura and N. Sugita, J- Organomet. Chem., 326, 3.5 (1987); m, 2,4859 (1987).
8.
D.H.R. Barton, D. Bridon and S.Z. Zard, Heterocycles,
9.
R. Sustmann and J. Lau, Chem. Ber., 119, 2531 (1986); Tetrahedron Letts. Yamamoto, A. Yamamoto and S. Ikeda, J. Am. Chem. Sot., 93, 3350 (lm’
(Received
in
USA 26 April
of Tellurium”,
1988)
in press.
Metals”, John Wiley and Sons, New Academic Press, New York, 1985.
Gordon and Breach Science
Chem., 194,277
Publishers
Inc., New
274 (1985); D.L.J.
(1980). 271 (1985); K. J. Org. Chem.,
25,449 (1987).
26, 4907 (1985); see also T.