Palladium-catalyzed allylic alkenylation of allylic alcohols with n-butyl acrylate

Article abstract of DOI:10.1039/b307705e

Various allylic alcohols reacted with n-butyl acrylate in the presence of p-toluenesulfonic anhydride and palladium catalysts to yield the corresponding n-butyl 2,5-dienoates with high regioselectivity.

Full text of DOI:10.1039/b307705e

Palladium-catalyzed allylic alkenylation of allylic alcohols with n-butyl
acrylate†
Naofumi Tsukada,* Tetsuo Sato and Yoshio Inoue
Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai
980-8579, Japan. E-mail: tsukada@aporg.che.tohoku.ac.jp; Fax: 81 22 217 5873; Tel: 81 22 217 5874
Received (in Cambridge, UK) 8th July 2003, Accepted 27th August 2003
First published as an Advance Article on the web 9th September 2003
Various allylic alcohols reacted with n-butyl acrylate in the
presence of p-toluenesulfonic anhydride and palladium
catalysts to yield the corresponding n-butyl 2,5-dienoates
with high regioselectivity.
butyl acrylate dimer was also produced. Although the reaction
of allyl mesylate gave similar results (entry 2), no product was
obtained by reaction of other allylic compounds such as allyl
bromide, allyl acetate, or allyl trifluoroacetate. Using triphenyl-
phosphine or tri(n-butyl)phosphine as a ligand, 1 and 2 were
obtained in low yields. In contrast, other phosphorus ligands,
such as tri(tert-butyl)phosphine, tri(o-tolyl)phosphine, and
triphenyl phosphite, were ineffective under the same conditions.
When the reaction was conducted in acetic acid, the selectivity
for 1 improved dramatically (entry 3). Satisfactory yield and
selectivity for 1 were achieved by using n-butyl acrylate both as
solvent and reagent (entry 4). The reaction at 60 °C afforded
similar results after 24 h (entry 5). Recently, we found that allyl
alcohol exhibited reactivity similar to allyl tosylate in the
Catalytic transformations of allylic compounds via p-allylpalla-
dium complexes have been extensively applied to organic
1
synthesis. Among them, allylic alkylation with soft carbon
nucleophiles has attracted much attention and been widely
investigated. However, allylic alkenylation is also one of the
most efficient and versatile methods for synthesis of 1,4-dienes.
2
3
Although various alkenylmetal reagents including tin, silane,
4
and boron have been employed for this purpose, alkenylation
with non-metalated alkenes is more desirable in terms of
simplicity and atom economy. However, to our knowledge,
this type of catalytic alkenylation has not been reported, except
for intramolecular metallo-ene reactions, while a wide range of
5
presence of Ts
alkynes. Although trifluoromethanesulfonic anhydride (Tf O)
2
O in the palladium-catalyzed reaction with
6
10
2
1
7
was not effective (entry 8), presumably due to instability (t =
2
8
13
alkenes has been applied in Mizoroki–Heck reactions. Al-
10 min at rt) of allyl triflate generated in situ, the alkenylation
though the reactions were not catalyzed by a palladium
complex, Mitsudo et al. reported that ruthenium complexes
catalyzed reactions of allyl carbonates and N,N-dimethylacryla-
of allyl alcohol with n-butyl acrylate in the presence of Ts
2
O or
methanesulfonic anhydride (Ms O) gave 1 with good selectivity
2
(entries 6 and 7). This system enhances the value of alkenylation
as a synthetic tool, because most of the substituted allyl
tosylates cannot be prepared owing to their thermal instabil-
ity.
9
mide. However, the products obtained were 1,3-dienes, not
1
,4-dienes. Recently, we found that rhodium-catalyzed reac-
tions of allyl tosylate with styrene derivatives yielded 1-aryl-
,4-dienes in most cases.10 Here, we report palladium-catalyzed
alkenylation of allylic alcohols with n-butyl acrylate in the
presence of p-toluenesulfonic anhydride (Ts O) to yield n-butyl
,5-dienoates.
Reactions of allyl tosylate and mesylate with n-butyl acrylate
were investigated first because we found that they are excellent
1
2
(1)
2
11
10
allylating agents in reactions with alkynes, arylalkenes, and
aromatic compounds.12 Treatment of allyl tosylate (0.5 mmol)
with n-butyl acrylate (2.0 mmol) in benzene in the presence of
Next, the alkenylation reactions of various allylic alcohols in
the presence of Ts O were investigated and the results are
summarized in Table 2. The reactions of 2-hexen-1-ol (3a) and
2 3 3 3
Pd (dba) ·CHCl (2.5 mol%) and PCy (5.0 mol%) at 80 °C for
2
1
2
2 h afforded n-butyl 2,5-hexadienoate (1) and n-butyl
,4-hexadienoate (2) in 42% combined yield with moderate
1
2
-hexen-3-ol (3b) yielded the same product, 4a (entries 1 and
). Neither branched isomers nor stereoisomers were obtained
selectivity (eqn. (1) and Table 1, entry 1). A trace amount of n-
in either case. Similarly, only (E,E)-1,4-diene 4b formed by
reaction using cinnamyl alcohol (3c) and 1-phenyl-2-propen-
1-ol (3d) (entries 3 and 4). These results indicate that the
alkenylation reactions proceed via common p-allylpalladium
intermediates. The reactions of prenyl alcohol (3e) and
Table 1 Pd-catalyzed alkenylation of allylic compounds with n-butyl
acrylate (BA)
a
b
c
Entry
X
Additive
Solvent (mL) Yield (%) Ratio (1 : 2)
3
-penten-2-ol (3f) selectively gave 1,4-dienes 4c and 4d,
1
2
3
4
5
6
7
8
a
OTs
OMs
OTs
OTs
OTs
OH
Benzene (0.5) 42
Benzene (0.5) 37
75 : 25
77 : 23
99 : 1
98 : 2
99 : 1
96 : 4
96 : 4
65 : 35
respectively, although small amounts of isomers also were
obtained (entries 5 and 6). The reaction of methallyl alcohol
(3h) yielded a large amount of a polymer, and the yield of
desired 1,4-diene 4f was low (entry 8). No product was obtained
using other alkenes such as acrylonitrile, N,N-dimethylacryla-
mide, or styrene.
AcOH (3)
69
90
81
63
56
9
d
BA (4 )
e
d
BA (4 )
d
Ts
Ms
Tf
2
O
BA (4 )
d
OH
OH
2
O
BA (4 )
d
2
O
BA (4 )
Brookhart studied reactivity of the cationic p-allylpalladium
+
2
Reaction conditions: allylic compound (0.5 mmol), BA (2.0 mmol),
complex
[(p-allyl)Pd(OEt
3 2 6 3
2
)(PCy
3
)] [BAr
4
]
(Ar
=
b
Pd
2
(dba)
3
·CHCl
3
(13 mmol), PCy
3
(25 mmol) at 80 °C, 12 h. GC yields.
[3,5-(CF ) C H ]) 5 with methyl acrylate by low-temperature
NMR spectroscopy, in which the formation of methyl 2,5-hex-
adienoate was observed at 15 °C, and the reaction intermediates
c
Determined by GC. Total amount. e Reaction was carried out at 60 °C for
d
24 h.
6
were detected at lower temperature. The alkenylation reported
here may proceed via similar reaction intermediates as shown in
†
Electronic supplementary information (ESI) available: spectral data for
Scheme 1. Oxidative addition of allylic tosylates (6)14 generated
compounds 1, 2, 4, and 5. See http://www.rsc.org/suppdata/cc/b3/
b307705e/
2
in situ from allylic alcohols and Ts O would give the
2
404
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Table 2 Pd-catalyzed alkenylation of allylic alcohols with n-butyl acrylate
tosylate, a cationic complex corresponding to 8 would not form
because acetate and halide coordinate to palladium more firmly
than does tosylate.
In summary, we found that the reaction of allyl tosylate with
2 3 3 3
n-butyl acrylate in the presence of Pd (dba) ·CHCl and PCy
selectively gave n-butyl 2,5-hexadienoate (1). Moreover, the
regioselective alkenylation of various allylic alcohols 3 to the
corresponding 1,4-dienes 4 was accomplished by addition of
a
2
(BA) in the presence of Ts O
Isolated
Entry Alcohol
Product
4a
yield (%)
1
2
3
4
3a
4a 73
3b
3d
74
4b 70
78
2
Ts O.
3c
Notes and references
4b
1
Reviews: S. A. Godleski, in Comprehensive Organic Synthesis; B. M.
Trost, I. Fleming, Eds.; Pergamon Press: NewYork, 1991, Vol. 4,
Chapter 3.3; J. Tsuji, Palladium Reagents and Catalysis. Innovations in
Organic Synthesis; John Wiley: Chichester, 1995.
5
6
3e
3f
4c
4d
70b
64b
2 D. A. Vosburg, C. D. Vanderwal and E. J. Sorenson, J. Am. Chem. Soc.,
2
2
002, 124, 4552; K. Itami, T. Koike and J. Yoshida, J. Am. Chem. Soc.,
001, 123, 6957; J. D. White, R. G. Carter, K. F. Sundermann and M.
7
8
3g
4e
4f
5
32
Wartmann, J. Am. Chem. Soc., 2001, 123, 5407; G. Reginato, A.
Mordini and M. Caracciolo, J. Org. Chem., 1997, 62, 6187; A. M.
Castano and A. M. Echavarren, Tetrahedron Lett., 1996, 37, 6587; R.
Ostwald, P.-Y. Chavant, H. Stadtmueller and P. Knochel, J. Org. Chem.,
28c
3h
1
994, 59, 4143; L. Del Valle, J. K. Stille and L. S. Hegedus, J. Org.
(4f : 5 =
Chem., 1990, 55, 3019; M. Kosugi, K. Ohashi, K. Akuzawa, T.
Kawazoe, H. Sano and T. Migita, Chem. Lett., 1987, 1237.
3 H. Matsuhashi, S. Asai, K. Hirabayashi, Y. Hatanaka, A. Mori and T.
Hiyama, Bull. Chem. Soc. Jpn., 1997, 70, 1943; H. Matsuhashi, Y.
Hatanaka, M. Kuroboshi and T. Hiyama, Tetrahedron Lett., 1995, 36,
5
3 : 47)
O (0.6 mmol),
(25 mmol) at 80 °C for 12 h.
a
Reaction conditions: 3 (0.5 mmol), BA (4 mL), Ts
Pd (dba) ·CHCl (13 mmol), PCy
Contaminated with a small amount of inseparable isomers. GC
yield.
2
2
3
3
3
b
c
1
539.
4
Y. Kobayashi, Y. Tokoro and K. Watatani, Eur. J. Org. Chem., 2000,
23, 3825; Y. Kobayashi, K. Watatani and Y. Tokoro, Tetrahedron Lett.,
1998, 39, 7533; Y. Kobayashi, R. Mizojiri and E. Ikeda, Synlett, 1995,
571; Y. Kobayashi, R. Mizojiri and E. Ikeda, J. Org. Chem., 1996, 61,
5391; Y. Kobayashi and E. Ikeda, J. Chem. Soc., Chem. Commun.,
1994, 1789.
5
6
B. M. Trost, Science, 1991, 254, 1471; B. M. Trost, Angew. Chem., Int.
Ed. Engl., 1995, 34, 259.
For stoichiometric reactions of p-allylpalladium complexes with
alkenes, see: G. M. Direnzo, P. S. White and M. Brookhart, J. Am.
Chem. Soc., 1996, 118, 6225; S. Mecking and W. Keim, Organome-
tallics, 1996, 15, 2650.
7
Reviews: W. Oppolzer, in Comprehensive Organic Synthesis; B. M.
Trost, I. Fleming, Eds.; Pergamon Press: NewYork, 1991, Vol. 5,
Chapter 8.3; W. Oppolzer, Angew. Chem., Int. Ed. Engl., 1989, 28, 38.
Mechanistic studies: E. Gómez-Bengoa, J. M. Cuerva, A. M. Echa-
varren and G. Martorell, Angew. Chem., Int. Ed. Engl., 1997, 36, 767; D.
J. Cárdenas, M. Alcamí, F. Cossío, M. Méndez and A. M. Echavarren,
Chem. Eur. J., 2003, 9, 96.
8
9
Reviews: R. F. Heck, in Comprehensive Organic Synthesis; B. M. Trost,
I. Fleming, Eds.; Pergamon Press: NewYork, 1991, Vol. 4, p. 833; S.
Bräse and A. de Meijere, in Metal-catalyzed Cross-coupling Reactions;
F. Diederich, P. J. Stang, Eds.; Wiley-VCH: Weinheim, 1998, p. 99.
T. Mitsudo, S.-W. Zhang, T. Kondo and Y. Watanabe, Tetrahedron
Lett., 1992, 33, 341.
1
1
0 N. Tsukada, T. Sato and Y. Inoue, Chem. Commun., 2001, 237.
1 N. Tsukada, S. Sugawara and Y. Inoue, Org. Lett., 2000, 2, 655; N.
Tsukada, S. Sugawara, K. Nakaoka and Y. Inoue, J. Org. Chem., 2003,
6
8, 5961.
Scheme 1
1
1
2 N. Tsukada, Y. Yagura, T. Sato and Y. Inoue, Synlett, 2003, 1431.
3 E. Vedejs, D. A. Engler and M. J. Mullins, J. Org. Chem., 1977, 42,
allylpalladium intermediate 7. Replacement of tosylate with n-
butyl acrylate is followed by its insertion, giving complex 9.
Elimination of product 4 from 9 affords hydride complex 10,
which reacts with 6, affording allylpalladium intermediate 7.
When allyl acetate and allyl halide were used instead of allyl
3
109.
1
4 Another possible intermediate is allyl acrylate, generated by transester-
ification between allyl alcohol and BA under acidic conditions.
However, allyl acrylate was not detected in the reaction of allyl alcohol
with BA in the presence of TsOH at 70 °C for 17 h in acetic acid.
CHEM. COMMUN., 2003, 2404–2405
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