Complex of tris(Z-styryl)phosphine with PdCl2 as a new catalyst for the Sonogashira reaction

Article abstract of DOI:10.1016/j.mencom.2008.11.010

The complex [(Z-PhCH=CH)₃P]₂PdCl₂ synthesized from tris(Z-styryl)phosphine and PdCl₂ (DMF, 90 °C, 15 min, yield 50%) is an active catalyst in the Sonogashira reaction (coupling between 1-ethynyl-4-nitrobenzene and 1-iodoanthra-9,10-quinone) and its activity is comparable with that of the complex [Ph₃P]₂PdCl₂, the most common catalyst for this type of reactions.

Full text of DOI:10.1016/j.mencom.2008.11.010

Mendeleev
Communications
Mendeleev Commun., 2008, 18, 318–319
Complex of tris(Z-styryl)phosphine with PdCl2
as a new catalyst for the Sonogashira reaction
a
b
a
a
Boris A. Trofimov,* Sergei F. Vasilevsky, Nina K. Gusarova, Svetlana F. Malysheva,
b
c
c
Denis S. Baranov, Victor I. Mamatyuk and Yurii V. Gatilov
a
b
c
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences,
6
64033 Irkutsk, Russian Federation. Fax: +7 3952 41 9346; e-mail: boris_trofimov@irioch.irk.ru
Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences,
30090 Novosibirsk, Russian Federation. Fax: +7 3832 34 2350; e-mail: vasilev@ns.kinetics.nsc.ru
6
N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of
Sciences, 630090 Novosibirsk, Russian Federation
DOI: 10.1016/j.mencom.2008.11.010
The complex [(Z-PhCH=CH) P] PdCl synthesized from tris(Z-styryl)phosphine and PdCl (DMF, 90 °C, 15 min, yield 50%) is
3
2
2
2
an active catalyst in the Sonogashira reaction (coupling between 1-ethynyl-4-nitrobenzene and 1-iodoanthra-9,10-quinone) and its
activity is comparable with that of the complex [Ph P] PdCl , the most common catalyst for this type of reactions.
3
2
2
The Pd–Cu-promoted coupling (the Sonogashira reaction) of
terminal acetylenes with haloaromatics and haloheteroaromatics
has become a powerful tool in modern organic synthesis. Now,
suggests a close likeness in properties of both ligands. One may
just wonder why tris(styryl)phosphine waited so long to be tried
as a ligand to prepare catalysts for the Sonogashira type reaction.
In this work, we synthesized complex 2 of tris(Z-styryl)phos-
1
it is a common place that the outcome of the reactions (yield,
chemo-, regio- and stereodirection, etc.) depends strongly on the
phine with PdCl and checked its activity in the Sonogashira
coupling. The preparation of complex 2 was carried out by
2
1
(b),2
ligand structure of the catalytic complexes.
Consequently,
special efforts are currently focused on the search for new
ligands, particularly bulky ones allowing more efficient and
heating (90 °C, 15 min) phosphine 1 with PdCl in DMF, the
2
3
†
molar ratio PdCl :phosphine 1 being l:2 (Scheme 1).
2
‡
available catalysts for the Sonogashira coupling to be designed.
The most common catalyst for this reaction remains the
According to X-ray analysis (Figure 1), complex 2 has the
structure of trans-bis[tris(Z-styryl)phosphino]palladium dichloride.
The coordination surroundings and geometry of the complex
are usual. The styryl moieties are non-planar, the torsion angles
between the double bond and benzene ring planes are 22.6–60.9°.
Previously,6 the reaction of phosphine 1 with PdCl4 in
aqueous alcohol in the presence of HCl was reported to afford
a complex having the composition similar to that of complex 2;
however, no X-ray structure was given. The complex was charac-
1
,2(a)
complex of thiphenylphosphine with PdCl2.
Preparation
of this ligand is usually based on hazardous PCl or POCl and
3
3
sodium metal or corresponding organomagnesium derivatives
under an inert atmosphere. Therefore, alternative more accessible
and save in preparation tertiary phosphines, particularly those
having new possibilities to be employed as ligands for catalyst
design, are always desirable.
2–
1
Previously, we have developed a one-pot stereoselective
synthesis of tris(Z-styryl)phosphine 1 directly from elemental
phosphorus and acetylene in the superbase system KOH–HMPA,
terized only by IR and H NMR (200 MHz) spectra and elemental
o
analysis, mp (166 C) being significantly different from that of
complex 2.
4
5
the yield being up to 55%. Later, phosphine 1 was synthesized
†
trans-[Tris(Z-styryl)phosphino]palladium dichloride 2. A mixture of
by the addition of phosphine gas (easily generated from phos-
PdCl (0.25 mmol) and tris(Z-styryl)phosphine (0.5 mmol) in 2 ml of DMF
2
phorus red and KOH in the H O–toluene system) to phenyl-
2
was stirred at 90 °C for 15 min until PdCl was dissolved. Hot solution
2
acetylene in the superbase system KOH–HMPA in 80% yield.
Thus, tris(styryl)phosphine is now one of the most available
tertiary phosphine, vinilog of triphenylphosphine, the most
applicable ligand in the Sonogashira coupling. The vinilogy
was filtered through dense funnel. After cooling, yellow precipitate was
washed with benzene to give complex 2, yield 50%, mp 188.5–189.5 °C.
1
H NMR (Bruker AV-300, 300.13 MHz, CDCl ) d: 6.26 (dt, 6H, =CHPh,
3
7
3
3
JHH 13.0 Hz, JHP 10.1 Hz, virtual coupling ), 6.82 (dt, 6H, =CH–P,
3J 13.0 Hz, J 18.4 Hz, virtual coupling ), 7.13–7.22 (m, 18H, m-H ,
2
7
HH
HP
Ph
m'-H , p-H ), 7.33 (m, 12H, o-H , o'-H ). IR (Bruker Vector-22, KBr
Ph
Ph
–
Ph
Ph
1
pellets, n/cm ): 1443, 1490, 1592 [C=C(Ph)], 1610 (C=C), 2996, 3025
[
‡
=CH(Ph)], 3050 (=CH).
Crystallographic data for 2: C H Cl P Pd, M = 858.06. Bruker P4
4
8
42
2 2
diffractometer [graphite monochromator, l(MoKα) = 0.71073 Å, 296 K,
w-scanning, 2q < 52°]. Orthorhombic system, space group P212121,
Cl
P
P
PdCl2
DMF
3
a = 12.204(2), b = 12.625(2), and c = 26.877(5) Å, V = 4141(1) Å , Z = 4,
P
Pd
–3
–1
dcalc = 1.376 g cm , m = 0.687 mm , R = 0.0654 [2221 reflections with
Cl
1
I ³ 2s(I)], wR = 0.1123 (all 4539 reflections), S = 0.998. All H atoms
2
were positioned geometrically and refined in riding model. Empirical
absorption correction was applied (transmission 0.89–0.99).
CCDC 706178 contains the supplementary crystallographic data for this
paper. These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
For details, see ‘Notice to Authors’, Mendeleev Commun., Issue 1, 2008.
1
2
Scheme 1
©
2008 Mendeleev Communications. All rights reserved.
– 318 –

Mendeleev Commun., 2008, 18, 318–319
As follows from the results obtained, complex 2 when applied
as a catalyst in the Sonogashira reaction has exhibited a very
similar activity compared to that of complex 3.
In conclusion, the Pd complex with tris(Z-styryl)phosphine,
[
(Z-PhCH=CH) P] PdCl was for the first time shown to be
P(2)
3 2 2
a promising catalyst for the Sonogashira coupling. Its easy
accessibility makes this complex a probable alternative to the
traditional catalyst [Ph P] PdCl for this type of reactions.
Pd(1)
Cl(1)
Cl(2)
P(1)
3
2
2
This work was supported by the Siberian Branch of the
Russian Academy of Sciences (Integration project no. 32) and
the Chemical Service Centre of SB RAS.
Figure 1 Molecular structure of complex 2 in a crystal (thermal ellipsoids
are drawn at 30% probability level). Selected bond lengths (Å): Pd–Cl
References
1
(a) K. Sonogashira, Y. Tohda and N. Hagihara, Tetrahedron Lett., 1975,
0, 4467; (b) L. Brandsma, S. F. Vasilevsky and H. D. Verkruijsse,
2.309(2), 2.311(2), Pd–P 2.336(2), 2.347(2), P–C 1.802(8)–1.831(9);
5
selected bond angles (°): Cl–Pd–Cl 179.86(9), P–Pd–P 179.72(8), Pd–P–C
Application of Transition Metal Catalysts in Organic Synthesis, Springer-
Verlag, Berlin, Heidelberg, 1998, 335; (c) S. F. Vasilevsky, E. V. Tretyakov
and J. Elguero, Adv. Heterocycl. Chem., 2002, 82, 1; (d) L. C. Whelan,
J. Traditional Medicines, 2004, 2281; (e) J. W. Y. Lam, Acc. Chem. Res.,
111.6(3)–115.3(3), C–P–C 99.7(3)–108.3(4).
The Sonogashira reaction has been performed using the
published results1 concerning the coupling between 1-ethynyl-
(b)
2
005, 745; (f) R. Chinchilla and C. Najera, Chem. Rev., 2007, 107, 874.
4-nitrobenzene and 1-iodoanthra-9,10-quinone in the presence of
2
3
(a) K. Okura, M. Furuune, M. Enna, M. Miura and M. Nomura, J. Org.
Chem., 1993, 58, 4716; (b) K. R. Buszek and Y.-M. Jeong, Tetrahedron
Lett., 1995, 36, 5677; (c) T. Hundertmark, A. F. Littke, S. L. Buchwald
and G. C. Fu, Org. Lett., 2000, 1729; (d) J. D. Morris, G. Docherty,
G. Woodward and M. Wills, Tetrahedron Lett., 2007, 48, 949.
(a) J.-C. Hierso, A. Fihri, R. Amardeil, Ph. Meunier, H. Doucet and
M. Santelli, Tetrahedron, 2005, 61, 9759; (b) M. Moreno-Manas, R. Pleixats
and A. Serra-Muns, Synlett, 2006, 3001; (c) Ya-H. Gan, J.-Ch. Lee
and F.-E. Hong, Polyhedron, 2006, 25, 3555; (d) V. M. Dembitsky and
D. O. Levitsky, Nat. Prod. Commun., 2006, 1, 405; (e) B. A. Trofimov,
S. F. Malysheva, N. K. Gusarova, V. A. Kuimov, N. A. Belogorlova and
B. G. Sukhov, Tetrahedron Lett., 2008, 49, 3480.
complex 2 and complex [Ph P] PdCl 3 leading to 1-[2-(4-nitro-
3
2
2
§
phenyl)ethynyl]anthra-9,10-quinone 4 (Scheme 2).
Addition of triphenylphosphine to the reaction mixture often
favors the Sonogashira coupling.
1
(b)
In the case of complex 2,
the response to such an addition turned out to be much more
pronounced than in the reaction with complex 3: the synthesis
was more than six times faster, as compared to that using a
¶
traditional catalyst. The substitution of triphenylphosphine for
phosphine 1 is unreasonable since this decreases the efficiency
of the reaction studied.
4
B. A. Trofimov, N. K. Gusarova, S. F. Malysheva, T. N. Rakhmatulina,
M. G. Voronkov, V. I. Dmitriev and S. I. Shaikhudinova, Phosphorus
Sulfur Silicon Relat. Elem., 1991, 55, 271.
I
O
O
CuI/Et3N/C6H6/Cat
0–60 °C, 1.5 h
5 B. A. Trofimov, N. K. Gusarova, S. N. Arbuzova, S. F. Malysheva,
R. den Besten and L. Brandsma, Synthesis, 1995, 387.
O N
2
+
5
6
A. N. Reznikov, I. M. Krivchun, N. K. Skvortsov, B. G. Sukhov and
S. F. Malysheva, Zh. Obshch. Khim., 2005, 75, 734 (Russ. J. Gen. Chem.,
2
005, 75, 694).
Cat = complex 2 (yield of 4, 92%),
complex 3 (yield of 4, 95%)
7 R. K. Harris, Can. J. Chem., 1964, 42, 2275.
8 A. A. Moroz, A. V. Piskunov and M. S. Shvartsberg, Izv. Akad. Nauk
SSSR, Ser. Khim., 1981, 386 (Bull. Acad. Sci. USSR, Div. Chem. Sci.,
O
O
1
981, 30, 304).
O N
2
4
Scheme 2
§
Coupling of 1-ethynyl-4-nitrobenzene with 1-iodoanthra-9,10-quinone
in the system CuI/Et N/Cat. A mixture of 1-ethynyl-4-nitrobenzene
3
(
2.5 mmol), 1-iodoanthra-9,10-quinone (2.5 mmol), CuI (0.015 mmol),
Received: 28th May 2008; Com. 08/3148
Et N (7 mmol) and Cat (0.007 mmol of complex 2 or 3) in 7 ml of
benzene was stirred under an argon atmosphere at 50 °C (1 h) and at
3
¶
Coupling of 1-ethynyl-4-nitrobenzene with 1-iodoanthra-9,10-quinone
60 °C (0.5 h). The reaction mixture was cooled and filtered through
in the system CuI/Et N/Ph P/Cat. The coupling reaction in the presence
3
3
alumina (2.5×10 mm), eluted with toluene (40 ml). The solvents were
evaporated under reduced pressure, and residue was recrystallized from
of Ph P (0.014 mmol) was carried out according to the procedure described
above, the yields of compound 4 being 95% when complex 2 was
3
§
toluene to give compound 4 in 92% (when complex 2 was used) and 95%
used [at 50 °C (1 h) and at 60 °C (0.5 h)] and 90% in the case of
complex 3 [at 50 °C (1 h) and at 60 °C (8 h)].
8
(in the case of complex 3) yields, mp 214–215 °C (lit., 214–215 °C).
–
319 –