Development of a highly selective and efficient catalyst for 1,3-butadiene dimerization

Article abstract of DOI:10.1021/ol048025g

(Chemical Equation Presented) A selective dimerization reaction of 1,3-butadiene in the presence of 2-propanol to give 1,3,7-octatriene has been developed. By modification of palladium carbene catalysts an unexpected selectivity switch from the telomeriza

Full text of DOI:10.1021/ol048025g

ORGANIC
LETTERS
2005
Vol. 7, No. 4
541-544
Development of a Highly Selective and
Efficient Catalyst for 1,3-Butadiene
Dimerization
Surendra Harkal,† Ralf Jackstell,† Franz Nierlich,‡ Dagmara Ortmann,‡ and
Matthias Beller*,†
Leibniz-Institut fu¨r Organische Katalyse (IfOK) an der UniVersita¨t Rostock e.V.,
Buchbinderstrasse 5-6, D-18055 Rostock, Germany, and Degussa AG,
Industriepark Marl, 45772 Marl, Germany
matthias.beller@ifok.uni-rostock.de
Received September 28, 2004 (Revised Manuscript Received December 21, 2004)
ABSTRACT
A selective dimerization reaction of 1,3-butadiene in the presence of 2-propanol to give 1,3,7-octatriene has been developed. By modification
of palladium carbene catalysts an unexpected selectivity switch from the telomerization to the dimerization product occurred. In applying the
1,3-bis(2,6-diisopropylphenyl)-4,5-dimethyl-3H-imidazolidenylpalladium(0) complex 9, unprecedented catalyst efficiency (TON > 80 000 and TOF
-
> 5000 h 1) has been obtained for this transformation.
Functionalization and refinement reactions of 1,3-butadiene
to provide more valuable organic building blocks and
Scheme 1. Telomerization of 1,3-Butadiene with Methanol
polymers are of significant interest to industrial chemistry
and catalysis. With respect to this area, in the past we have
been interested in the understanding and practical application
of palladium-catalyzed telomerization reactions of 1,3-
butadiene and methanol. In general, telomerization reactions
are defined as dimerization of two molecules of a 1,3-diene
in the presence of an appropriate nucleophile HX, for ex-
ample, methanol (Scheme 1).1 The main product of this 100%
atom-efficient reaction is the linear 1-methoxy-2,7-octadiene
1. Major byproducts include the branched 3-methoxy-1,7-
give 1,3,7-octatriene 3 as the major product. Here, we report
octadiene 2, 1,3,7-octatriene 3, and 4-vinylcyclohexene 4.
the outcome of this study which presents the most efficient
process for 3 known to date.
Recently, we have shown that monocarbenepalladium-(0)-
olefin complexes are highly active and productive catalysts
Octatrienes have been reported to be useful intermediates
for the manufacturing of butylene oligomers with molecular
weights of 350-500,3 1,5- and 1,6-octadienes,4 of different
polymers,5 and for the synthesis of bicyclic alcohols.6
In the past, palladium-phosphine complexes such as
Pd(PPh3)4 (TON ) 1834)7 or palladium-phosphonite com-
for the telomerization of 1,3-butadiene with various alcohols.2
While studying the telomerization reaction in the presence
of 2-propanol, we observed a dramatic selectivity switch to
† Leibniz-Institut fu¨r Organische Katalyse (IfOK) an der Universita¨t
Rostock e.V.
‡ Degussa AG.
10.1021/ol048025g CCC: $30.25
© 2005 American Chemical Society
Published on Web 01/22/2005

plexes (TON ) 3482)8 have been reported to catalyze the
linear dimerization of 1,3-butadiene to 1,3,7-octatriene 3.
Interestingly, the catalyst activity and selectivity is influenced
by the presence of CO2.9 Recently, the reaction of 1,3-
butadiene with water under suitable conditions (0.2 mol %
Pd(OAc)2, 0.6 mol %, PPh3, 90 °C) provided 3 in moderate
to good yield.10 In addition, it is known that the linear
dimerization of 1,3-butadiene can be carried out using co-
balt-,11 iron-,12 and rhodium-based13 catalyst systems to form
5-methyl-1,3,6-heptatriene, 1,3,6-octatriene, and 2,4,6-octa-
triene while dimerization with nickel catalysts usually gives
1,5-cyclooctadiene.14 Basically, all procedures known to date
for the dimerization of 1,3-butadiene suffer from low catalyst
turnover numbers (TON < 3500) and/or low catalyst activity
(TOF < 450).
palladium(0) catalysts are stable for months and can be easily
handled even under air.16
As shown in Table 1 (entries 1-2), Pd(dba)2 and Pd(OAc)2
did not result in any reaction (entries 1-2), while the known
Table 1. Dimerization of 1,3-Butadiene in 2-Propanol with
Different Catalystsa
yieldb chemoselectivityc
TOFd
TON (h-1
entry
catalyst
Pd(dba)2
Pd(OAc)2
Pd(OAc)2/3 PPh3 16
5
6
7
8
9
(%)
(%)
)
1
2
3
4
5
6
7
8
9
0
0
84
17
16
31
62
95
93
3200 200
3400 212
3200 200
6200 387
12 400 775
18 400 1150
16 600 1037
17
16
31
62
92
83
As a starting point of our investigation, we tested different
(carbene)palladium(0)-dvds (dvds ) 1,3-dimethyldivinyl-
siloxane) complexes15 5-9 (Figure 1) for the dimerization
Pd(OAc)2/4 L
a General conditions: Pd ) 0.005 mol %, 16 h, 70 °C, 1.0 mol % NaOR,
ROH/1,3-butadiene ) 2:1, 3 mL of THF, diglyme as internal standard.
b Yield of 1,3,7-octatriene. c Chemoselectivity ) (yield of octatriene)/(yield
of telomer + octatriene + 4-vinylcyclohexene) × 100. d Calculated with
respect to 1,3,7-octatriene. L ) 1,3-bis(2,6-diisopropylphenyl)-4,5-dimethyl-
3H-imidazol-1-ium bromide.
system Pd(OAc)2/PPh3 gave 16% of 1,3,7-octatriene 3 (entry
3). Applying monocarbenepalladium(0)-olefin complexes
5-7, which have a mesityl group attached to the carbene
nitrogen atoms, significantly higher activity is obtained
(100% conversion). Unfortunately, the selectivity for the
desired product 3 is low (17-31% of 1,3,7-octatriene).
Instead, mainly the octadienyl ethers 1 and 2 (Table 1, entries
4-6) are produced. However, by applying complex 8, which
resembles 5 except for the 2,6-diisopropylphenyl group
attached to the carbene nitrogen, the yield of 3 is increased
Figure 1. Monocarbenepalladium(0) dvds complexes.
of 1,3-butadiene in 2-propanol as solvent and compared their
performance to standard palladium catalysts. The applied
(1) (a) Estrine, B.; Soler, R.; Damez, C.; Bouquillon, S.; Henin, F.;
Muzart, J. Green Chem. 2003, 5, 686-689. (b) Magna, L.; Chauvin, Y.;
Niccolai, G. P.; Basset, J.-M. Organometallics 2003, 22, 4418-4425. (c)
Drent, E.; Eberhard, M. R.; Van der Made, R. H.; Pringle, P. G. WO
2003040065, 2003. (d) Vollmu¨ller, F.; Ma¨gerlein, W.; Klein, S.; Krause,
J.; Beller, M. AdV. Synth. Catal. 2001, 343, 29-33. (e) Vollmu¨ller, F.; Klein,
S.; Krause, J.; Ma¨gerlein, W.; Beller, M. Eur. J. Inorg. Chem. 2000, 1825-
1832. (f) Benvenuti, F.; Carlini, C.; Marchionna, M.; Patrini, R.; Raspolli
Galletti, A. M.; Sbrana, G. J. Mol. Catal. 1999, 140, 139-155. (g) Basato,
M.; Crociani, L.; Benvenuti, F.; Raspolli Galletti, A. M.; Sbrana, G. J. Mol.
Catal. 1999, 145, 313-316. (h) Patrini, R.; Lami, M.; Marchionna, M.;
Benvenuti, F.; Raspolli Galletti, A. M.; Sbrana, G. J. Mol. Catal. 1998,
129, 179-189. (i) Jolly, P. W. Angew. Chem. 1985, 97, 279-291; Angew.
Chem., Int. Ed. Engl. 1985, 24, 283. (j) Grenouillet, P.; Neibecker, D.;
Poirier, J.; Tkatchenko, I. Angew. Chem. 1982, 94, 796-797; Angew. Chem.,
Int. Ed. Engl. 1982, 21, 767-768. (k) Perree-Fauvet, M.; Chauvin, Y.
Tetrahedron Lett. 1975, 4559. (l) Commereuc, D.; Chauvin, Y. Bull. Soc.
Chim. Fr. 1974, 652-656. (m) Beger, J.; Duschek, C.; Fu¨llbier, H.; Gaube,
W. J. Prakt. Chem. 1974, 316, 26-42. (n) Beger, J.; Reichel, H. J. Prakt.
Chem. 1973, 315, 1067-1076. (o) Takahashi, S.; Shibano, T.; Hagihara,
N. Tetrahedron Lett. 1967, 2451-2453.
(4) Wayne, G. L. (du Pont de Nemours, E. I., and Co.). US 3673270,
1972.
(5) Collins, D. J.; Bryn, H.; Kwan, W. P.; Marie, B. S. (Procter and
Gamble Company, USA.; Shell Oil Co.) PCT INT. Appl. WO 9621474,
1996.
(6) Brown, H. C.; Negishi, E. J. Am. Chem. Soc. 1969, 91, 1224-1225.
(7) Takahashi, S.; Shibano, T.; Hagihara, N. Bull. Chem. Soc. Jpn. 1968,
41, 454-460.
(8) Keiichi, S.; Yoko, S.; Iwao, N. JP. 09030993, 1995, Jpn. Kokai
Tokkyo Koho, 1997, 21pp.
(9) Musuco, A.; Silvani, A. J. Organomet. Chem. 1975, 88, C41-43.
(10) Lee, B. I.; Lee, K. H.; Lee, J. S. J. Mol. Catal. A: Chem. 2001,
166, 233-42.
(11) (a) Otsuka, S.; Taketomi, T. J. Chem. Soc. Jpn. 1963, 66, 1094. (b)
Saito, T.; Ono, T.; Uchida, Y.; Taketomi, A. J. Chem. Soc. Jpn. 1963, 66,
1099. (c) Otsuka, S.; Taketomi, T. Eur. Polym. J. 1966, 2, 289. (d)
Witenberg, D. Angew. Chem. 1963, 75, 1124. (e) Tanaka, S.; Mabuchi, K.;
Shimazaki, N. J. Org. Chem. 1964, 29, 1626.
(12) Takahasi, H.; Tai, S.; Yamaguchi, M. J. Org. Chem. 1965, 30, 1661.
(13) Alderson, T.; Jenner, E. L.; Lindsey, R. V. J. Am. Chem. Soc. 1964,
87, 5638.
(2) (a) Jackstell, R.; Andreu, M. G.; Frisch, A.; Selvakumar, K.; Zapf,
A.; Klein, H.; Spannenberg, A.; Ro¨ttger, D.; Briel, O.; Karch, R.; Beller,
M. Angew. Chem., Int. Ed. 2002, 41, 986-9. (b) Jackstell, R.; Frisch, A.;
Ro¨ttger, D.; Malaun, M.; Bildstein, B.; Beller, M. J. Mol. Catal A: Chem.
2002, 185, 105-112; (c) Jackstell, R.; Harkal, S.; Jiao, H.; Spannenberg,
A.; Borgmann, C.; Ro¨ttger, D.; Nierlich, F.; Elliot, M.; Niven, S.; Cavell,
K.; Navarro, O.; Viciu, M. S.; Nolan, S. P.; Beller, M. Chem. Eur. J. 2004,
10, 3891-3900.
(14) An exception is the linear dimerization in alcoholic media with low-
valent nickel complexes: (a) Mu¨ller, H.; Wittenberg, D.; Seibt, H.; Scharf,
E. Angew. Chem. 1965, 77, 318. (b) Feldman, J.; Saffer, B. A.; Frampton,
O. D. U.S. Pat. 3284529, 1966; Chem. Abstr. 1967, 66, 28373.
(15) (a) Andreu, M. G.; Zapf, A.; Beller, M. Chem. Commun. 2000,
2475-2476. (b) Krause, J.; Haack, K.; -J.; Cestaric, G.; Goddard, R.;
Po¨rschke, K.-P. Chem. Commun. 1998, 1291-1292.
(16) Similar palladium-carbene catalysts are commercially available from
STREM.
(3) Pantukh, B. I.; Egoricheva, S. A.; Shulmanas, S. V. RU 2160285,
2000.
542
Org. Lett., Vol. 7, No. 4, 2005

to 62% (Table 1, entry 7). Surprisingly, using complex 9,
which has two extra methyl groups on the C-4 and C-5
position of the imidazole ring, provided excellent yield (92%)
of 3 with 95% selectivity and a turnover number TON )
18 400. Interestingly, the in situ prepared catalyst 9 gave
similar results (Table 1, entry 9). It is important to note that
in general 1,3,7-octatriene 3 is obtained as a mixture of two
isomers (cis and trans) in a ratio of 1:1.7. Spectroscopic
studies (NMR, UV) rule out any formation of the corre-
sponding conjugated triene.
conversion (Table 2, entries 1-2). In the presence of primary
alcohols, predominantly octadienyl ethers were obtained
(Table 2, entries 3-5) due to the easier attack of the alcohol
on the intermediate palladium allyl complex (see also Scheme
2). As expected, in the presence of the secondary alcohol
Scheme 2. Proposed Mechanism for the Dimerization/
Telomerization of 1,3-Butadiene with Alcohols
Next, we were interested in the effect of different alcohols
on the selectivity of the dimerization process. Table 2 shows
Table 2. Dimerization of 1,3-Butadiene with Different
Alcohols and Phenolsa
cyclohexanol 3 is obtained in good yield (83%) (Table 2,
entry 7). However, by using more hindered alcohols such
as 2,4-dimethyl-3-pentanol and t-BuOH very low conversion
is seen (Table 2, entries 8 and 9). This is also true for
phenols.
By optimizing the catalyst efficiency of 9 in the presence
of 2-propanol (Table 2, entries 12-15) turnover numbers
>80 000 and catalyst activity >5000 h-1 are observed at 70
°C. To the best of our knowledge, this is the highest catalyst
productivity and activity reported for any 1,3-diene dimer-
ization reaction. Interestingly, even at lower temperature (50
°C) 1,3-butadiene is smoothly dimerized in 84% yield (Table
2, entry 12).
With regard to the mechanism of the reaction the basic
question is whether 3 is formed directly from the [Pd(car-
bene)(η1,η2-C8H13)] species 11 or via 12 with subsequent
elimination. The generally accepted mechanism of the
telomerization reaction is shown in Scheme 2. Important
mechanistic studies of the telomerization of alcohols and 1,3-
butadiene in the presence of a palladium phosphine catalyst
have been performed by Jolly and co-workers.17 More
recently, we also proposed a possible mechanism for this
reaction.18
a General conditions: 16 h, 0.005 mol % of catalyst 9, 1.0 mol % of
NaOR, ROH/1,3-butadiene ) 2:1, 3 mL of THF, 70 °C, diglyme as internal
standard. b Chemoselectivity ) (yield of 1)/(yield of 1 + 2 + 3 +
vinylcyclohexene) × 100. c Calculated with respect to 1,3,7-octatriene.
d Toluene instead of ROH. e THF instead of ROH. f Catalyst ) 0.001 mol
%. g NaOR ) NaOtBu. h Temperature 50 °C. i 0.25 equiv of ROH with
respect to 1,3-butadiene. j Pd/L ) 1:10, L ) 1,3-bis(2,6-diisopropylphenyl)-
4,5-dimethyl-3H-imidazol-1-ium bromide.
Earlier, Smutny had shown that, under suitable conditions,
1-phenoxy-2,7-octadiene can be converted to 1,3,7-octatriene
(17) (a) Benn, R.; Jolly, P. W.; Joswig, T.; Mynott, R.; Schick, K.-P. Z.
Naturforsch. 1986, 41b, 680-691. (b) Jolly, P. W.; Mynott, R.; Raspel,
B.; Schick, K.-P. Organometallics 1986, 5, 473-481. (c) Jolly, P. W. Angew.
Chem. 1985, 97, 279-291; Angew. Chem., Int. Ed. Engl. 1985, 24, 283-
295.
(18) Vollmu¨ller, F.; Klein, S.; Krause, J.; Ma¨gerlein, W.; Beller, M. Eur.
J. Inorg. Chem. 2000, 1825-1832.
a summary of the results obtained in the presence of catalyst
9. Using aprotic solvents such as toluene and THF led to no
Org. Lett., Vol. 7, No. 4, 2005
543

3 in good yield and conversion;19 in addition, Keim and co-
workers proposed a similar mechanism for the formation of
3.20 However, this mechanistic proposal is not supported by
the results shown in Table 2.
Hence, we performed catalytic reactions of 1-isopropoxy-
2,7-octadiene in the presence of 0.005 mol % of complex
9 in 2-propanol under typical reaction conditions (70 °C,
16 h).
poxide ion instead of adding to the allylic terminus of C1 or
C3, abstracts preferentially a proton on C4 in the presence
of 9 to give 1,3,7-octatriene via â-hydrogen elimination.
In summary, we have developed a highly productive and
active catalyst system 9 for the dimerization of 1,3-butadiene
to 1,3,7-octatriene. For the first time, this catalyst seems to
fulfill the criteria required for industrial application of this
reaction.
As shown in Scheme 3, 97% of the used 1-isopropoxy-
2,7-octadiene was reisolated after the reaction. Obviously,
Acknowledgment. This work was supported by Degussa
AG (Oxeno Olefinchemie GmbH), the Bundesministerium
fu¨r Bildung und Forschung (BMBF), and the state of
Mecklenburg-Vorpommern. Excellent analytical services
were provided by Mrs. S. Buchholz and Dr. C. Fischer
(IfOK).
Scheme 3. Formation of 3 via 1 and 2
Supporting Information Available: Experimental pro-
cedures. This material is available free of charge via the
Internet at http://pubs.acs.org.
OL048025G
(19) Smutny, E. J. J. Am. Chem. Soc. 1967, 89, 6793-6794.
(20) Durocher, A.; Keim, W.; Voncken, P. Ph.D. Dissertation, Aachen
University, Aachen, 1976.
formation of 1,3,7-octatriene formation via 12 is ruled out.
Thus, as shown in Scheme 2, we believe that the isopro-
544
Org. Lett., Vol. 7, No. 4, 2005