4-dimethylaminopyridine, an efficient ligand for the Heck reaction in aqueous media [2]

Full text of DOI:10.1007/s11172-007-0165-2

Russian Chemical Bulletin, International Edition, Vol. 56, No. 5, pp. 1093—1094, May, 2007
1093
4ꢀDimethylaminopyridine, an efficient ligand
for the Heck reaction in aqueous media
D. V. Evdokimov and N. A. Bumaginꢀ
Department of Chemistry, M. V. Lomonosov Moscow State University,
1 Leninskie Gory, 119992 Moscow, Russian Federation.
Fax: +7 (495) 932 8846. Eꢀmail: bumagin@org.chem.msu.ru
Key words: arylation, olefins, the Heck reaction, cinnamic acids, palladium, water.
Scheme 1
The Heck reaction, a palladiumꢀcatalyzed crossꢀcouꢀ
pling of olefins with aryl and vinyl halides,1,2 is widely
employed in modern organic synthesis for preparation of
alkenes containing virtually any functional groups.3 The
reaction is usually carried out in organic solvents with
prolonged heating in the presence of palladium complexes
with phosphine ligands (1—5 mol.%) and an appropriate
base. In recent years, catalysts based on phosphorusꢀ,4
sulfurꢀ,5 and nitrogenꢀcontaining6 palladacycles and
carbene ligands7 have been proposed instead of palladium
complexes with phosphine. However, even in the presꢀ
ence of new, more efficient catalysts, the reaction is comꢀ
pleted at 100—150 °C in 24—90 h (see Ref. 8). For this
reason, a search for active palladium catalysts is still among
the most important tasks in the study of catalytic reacꢀ
tions.9 Another promising line (from the practical standꢀ
point) in this area is the use of water instead of toxic and
difficultꢀtoꢀrecover organic solvents, because water is the
most accessible, safe, and ecologically pure solvent.10
Here we showed for the first time, with reactions of
acrylic acid 1 with aryl halides 2 as examples (Scheme 1),
that a complex of palladium dichloride with 4ꢀdimethylꢀ
aminopyridine (DMAP) PdCl2(DMAP)4 is an efficient
catalyst for the Heck reaction in water and aqueous ethylꢀ
ene glycol. The catalytic activity of the complex was so
high that reactions of waterꢀsoluble (in the presence of a
base) 4ꢀiodobenzoic (2a) and 5ꢀiodosalicylic acids (2b) in
water were completed at 100 °C in 4 and 2 min, respecꢀ
tively, the catalyst concentration being 0.1 mol.%. Bromoꢀ
benzoic acids (e.g., 2c) reacted with acrylic acid under
analogous conditions; however, the reaction duration was
50 min. In addition, sodium formate (4.3 mol.%) should
be used as a promoter.
Reagents and conditions: PdCl2(DMAP)4 (0.1—0.4 mol.%),
K2CO3, H2O or H2O—HOCH2CH2OH (1 : 1), 100 or 111 °C
2, 3
a
b
c
d
R1
H
CO2H
CO2H
H
R2
CO2H
OH
H
Ac
Hal
I
I
Br
Br
Br
Yield of 3 (%)
86
97
85
93
91
e
H
OMe
(E)ꢀ3ꢀ(4ꢀacetylphenyl)propꢀ2ꢀenoic acid 3d in 93% yield
as the sole product, while in the case of 4ꢀbromoanisole
2e with an electronꢀdonating methoxy group, the reacꢀ
tion time increased to 1.4 h (the yield of product 3e
was 91%).
According to the literature data,11 a comparable cataꢀ
lytic activity in the Heck reaction is exhibited by a complex
of Pd(OAc)2 with Nꢀphenylurea (DMF, 0.1 mol.% Pd,
130 °C, 2—6 h, 81—99%). However, the reaction time is
absolutely independent of the nature of the substituent in
the aromatic ring of aryl halide and in some cases, aryl
iodides are substantially less reactive than the correspondꢀ
ing aryl bromides.
The reactions with waterꢀinsoluble aryl bromides 2d,e
were carried out in aqueous ethylene glycol
(HOCH2CH2OH : H2O = 1 : 1) at 111 °C. The reaction
with 4ꢀbromoacetophenone 2d containing a strong elecꢀ
tronꢀwithdrawing substituent in the presence of the cataꢀ
lyst (0.4 mol.%) was completed in 10 min, producing
Tetrakis(4ꢀdimethylaminopyridine)palladium(II) dichloride.
A solution of 4ꢀdimethylaminopyridine (1.2 g, 9.8 mmol)
in MeCN (50 mL) was added to PdCl2(MeCN)2 (0.572 g,
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1052—1053, May, 2007.
1066ꢀ5285/07/5605ꢀ1093 © 2007 Springer Science+Business Media, Inc.

1094
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 5, May, 2007
Evdokimov and Bumagin
2.2 mmol). The mixture was refluxed for 10 min. Then ethanol
(10 mL) was added and reflux was continued for an additional
10 min. The solvent was removed in a rotary evaporator. The
solid residue was washed with acetonitrile (5×10 mL) on a Schott
glass filter and dried in air. Tetrakis(4ꢀdimethylaminopyriꢀ
dine)palladium(II) dichloride was obtained as a white powder.
The yield was 1.409 g (96%), decomp. at 295—300 °C.
Found (%): C, 50.84; H, 6.21; N, 16.67. C28H40Cl2N8Pd. Calꢀ
(E)ꢀ3ꢀ(4ꢀMethoxyphenyl)propꢀ2ꢀenoic acid (3e) was obtained
analogously. The yield was 91%, m.p..176—177 °C (cf. Ref. 15:
m.p. 174 °C). 1H NMR (400 MHz, DMSOꢀd6), δ: 3.76 (s, 3 H,
Me); 6.36 (d, 1 H, C(8)H, J = 15.9 Hz); 6.94 (d, 2 H, C(3)H,
C(5)H, J = 8.6 Hz); 7.55 (d, 1 H, C(7)H, J = 16.2 Hz); 7.60 (d,
2 H, C(2)H, C(6)H, J = 8.8 Hz); 12.22 (br.s, 1 H, OH).
References
1
culated (%): C, 50.50; H, 6.05; N, 16.83. H NMR (400 MHz,
D2O), δ: 2.19 (br.s, 6 H, Me); 6.10 (br.s, 2 H, H(3), H(5)); 8.72
(br.s, 2 H, H(2), H(6)). 13C NMR (100 MHz, D2O), δ: 37.88
(Me); 108.52 (C(3), C(5)); 149.03 (C(2), C(6)); 154.16 (C(4)),
1. T. Mizoroki, K. Mori, and A. Ozaki, Bull. Chem. Soc. Jpn,
1971, 44, 581.
2. R. F. Heck and J. P. Nolley, Jr., J. Org. Chem., 1972,
37, 2320.
3. I. P. Beletskaya and A. V. Cheprakov, Chem. Rev., 2000,
100, 3009.
1
DMAP. H NMR (400 MHz, D2O), δ: 2.66 (s, 6 H, Me); 6.25
(dd, 2 H, H(3), H(5), J = 5.1 Hz, J = 1.6 Hz); 7.81 (dd, 2 H,
H(2), H(6), J = 5.1 Hz, J = 1.5 Hz). 13C NMR (D2O, 100 MHz),
δ: 38.01 (Me); 106.57 (C(3), C(5)); 147.87 (C(2), C(6));
154.66 C(4)).
4. F. Miyazaki, K. Yamaguchi, and M. Shibasaki, Tetrahedron
Lett., 1998, 39, 7379; D. MoralesꢀMorales, R. Redon,
C. Yung, and C. M. Jensen, Chem. Commun., 2000, 1619;
R. B. Bedford and S. L. Welch, Chem. Commun., 2001, 129;
S. Gibson, D. F. Foster, G. R. Eastam, R. P. Tooze, and
D. J. ColeꢀHamilton, Chem. Commun., 2001, 779.
5. A. S. Gruber, D. Z. Zim, G. Ebeling, A. L. Monteriro, and
J. Dupont, Org. Lett., 2000, 1287; D. E. Bergbreiter, P. L.
Osburn, A. Wilson, and E. Sink, J. Am. Chem. Soc., 2000,
122, 9058.
6. M. Ohff, A. Ohff, and D. Milstein, Chem. Commun., 1999,
357; S. Iyer and C. Ramesh, Tetrahedron Lett., 2000, 41,
8981; D. A. Alonso, C. Najera, and M. C. Pacheco, Adv.
Synth. Catal., 2002, 343, 172; C. Rocaboy and J. A. Gladysz,
Org. Lett., 2002, 4, 1993; C. S. Consorti, M. L. Zanini,
S. Leal, G. Ebeling, and J. Dupont, Org. Lett., 2003, 5, 983.
7. D. Bourissou, O. Guerret, F. P. Gabbaý, and C. B. Bertrand,
Chem. Rev., 2000, 100, 39; S. P. Nolan, H. M. Lee, and
C. Yang, Org. Lett., 2001, 3, 1511; W. A. Herrmann, Angew.
Chem., Int. Ed., 2002, 41, 1290.
8. Q. Yao, E. P. Kinney, and Z. Yang, J. Org. Chem., 2003,
68, 7528.
9. F. Bellina, A. Carpita, and R. Rossi, Synthesis, 2004, 2419.
10. N. E. Leadbeater, Chem. Commun., 2005, 2881; C. J. Li,
Chem. Rev., 2005, 105, 3095.
11. X. Cui, Y. Zhou, N. Wang, L. Liu, and Q.ꢀX. Guo, Tetraꢀ
hedron Lett., 2007, 48, 163.
12. N. A. Bumagin, V. V. Bykov, and I. P. Beletskaya, Zh. Org.
Khim., 1995, 31, 481 [Russ. J. Org. Chem., 1995, 31 (Engl.
Transl.)].
(E)ꢀ3ꢀ(4ꢀAcetylphenyl)propꢀ2ꢀenoic acid (3d). An aqueous
solution of K2CO3 (c = 3 mol L–1, 5 mL, 15 mmol), ethylene
glycol (5 mL), acrylic acid (0.91 mL, 13.3 mmol), EtOH
(0.5 mL), sodium formate (30 mg, 0.44 mmol, 4.3 mol.%), and
PdCl2(DMAP)4 (26.4 mg, 0.04 mmol) were added to 4ꢀbromoꢀ
acetophenone 2d (2.02 g, 10.15 mmol). The mixture was careꢀ
fully stirred for 5 min and refluxed until palladium black preꢀ
cipitated. The cooled solution was acidified to pH 1. The
precipitate that formed was filtered off, washed with water
(30 mL), and dried. (E)ꢀ3ꢀ(4ꢀAcetylphenyl)propꢀ2ꢀenoic acid
3d was obtained as a white powder. The yield was 1.79 g (93%),
m.p. 224—225 °C (cf. Ref. 12: m.p. 223—225 °C). 1H NMR
(400 MHz, DMSOꢀd6), δ: 2.53 (s, 3 H, Me); 6.59 (d, 1 H,
C(8)H, J = 16.2 Hz); 7.59 (d, 1 H, C(7)H, J = 16.2 Hz); 7.73 (d,
2 H, C(2)H, C(6)H, J = 8.1 Hz); 7.90 (d, 2 H, C(3)H, C(5)H,
J = 8.1 Hz); 12.55 (br.s, 1 H, OH).
4ꢀ[(E)ꢀ2ꢀCarboxyvinyl]benzoic acid (3a) was obtained analoꢀ
gously in water at 100 °C, without addition of sodium formate or
ethanol. The yield was 86%, m.p.. 358—360 °C (cf. Ref. 13: m.p.
363 °C). 1H NMR (400 MHz, DMSOꢀd6), δ: 6.61 (d, 1 H,
C(8)H, J = 16.2 Hz); 7.62 (d, 1 H, C(7)H, J = 16.2 Hz); 7.76 (d,
2 H, C(2)H, C(6)H, J = 8.3 Hz); 7.94 (d, 2 H, C(3)H, C(5)H,
J = 8.3 Hz); 12.82 (br.s, 2 H, OH).
5ꢀ[(E)ꢀ2ꢀCarboxyvinyl]ꢀ2ꢀhydroxybenzoic acid (3b) was obꢀ
tained analogously in water at 100 °C, without addition of soꢀ
dium formate or ethanol. The yield was 97%, m.p. 275—277 °C
1
(cf. Ref. 14: m.p. 279 °C). H NMR (400 MHz, DMSOꢀd6), δ:
6.37 (d, 1 H, C(8)H, J = 15.9 Hz); 6.96 (d, 1 H, C(5)H, J =
8.6 Hz); 7.53 (d, 1 H, C(7)H, J = 15.9 Hz); 7.84 (dd, 1 H,
C(6)H, J = 8.8 Hz, J = 2.3 Hz); 7.99 (d, 1 H, C(2)H, J =
2.0 Hz); 12.11 (br.s, 2 H, OH).
3ꢀ[(E)ꢀ2ꢀCarboxyvinyl]benzoic acid (3c) was obtained analoꢀ
gously in water at 100 °C, without addition of ethanol. The yield
was 85%, m.p.. 284—286 °C (cf. Ref. 15: m.p. 278—280 °C).
1H NMR (400 MHz, DMSOꢀd6), δ: 6.57 (d, 1 H, C(8)H, J =
16.2 Hz); 7.52 (m, 1 H, C(5)H, J = 7.8 Hz); 7.64 (d, 1 H,
C(7)H, J = 15.9 Hz); 7.93 (m, 2 H, C(4)H, C(6)H); 8.14 (s,
1 H, C(2)H); 12.80 (br.s, 2 H, OH).
13. R. Kluger, L. Shen, H. Xiao, and R. T. Jones, J. Am. Chem.
Soc., 1996, 118, 8782.
14. G. Orzalesi, R. Selleri, O. Caldini, and E. Mura, Farm. Ed.
Sci., 1967, 22, 450.
15. G. H. Cleland, J. Org. Chem., 1969, 34, 744.
Received March 28, 2007;
in revised form May 11, 2007