Cationic η3-allyl complexes. 21. Telomerization of buta-1,3-diene with Z-H compounds mediated by group 10 complexes

Article abstract of DOI:10.1016/S0022-328X(98)00789-X

Cationic (η³-allyl) complexes of general formula [(η³-allyl)M(ligand)₂]⁺Y^-, where Y^- is a non-coordinating anion (BF₄^-, ClO₄^-, BF₄^-) have been examined in telomerization reactions of buta-1,3-diene with representative nucleophiles. No reaction are observed for nickel complexes, due to their high reactivity versus nucleophiles. With palladium complexes, the reaction only occurs with alcohols and provides an increased selectivity for telomers with more than two diene units, leading to C₁₆, C₂₄ and even higher ethers. Although much less reactive, platinum complexes can also produce higher telomers when hydrogenosilanes are used. It is proposed, at least in the case of palladium, that the formation of C₁₆ and C₂₄ ethers arises from the coupling of C₈ units within dimeric palladium intermediates with the telogen acting as a bridging ligand.

Full text of DOI:10.1016/S0022-328X(98)00789-X

Journal of Organometallic Chemistry 569 (1998) 203–215
Cationic p3-allyl complexes. 21. Telomerization of buta-1,3-diene with
Z–H compounds mediated by group 10 complexes
Faouzi Bouachir a, Pierre Grenouillet b, Denis Neibecker c, Jacques Poirier c, Igor Tkatchenko c,*
a Faculte´ des Sciences, Uni6ersite´ de Monastir, Monastir, Tunisia
b Laboratoire de Ge´nie des Proce´de´s Catalytiques, URA CNRS2211, CPE Lyon, 43 boule6ard du 11 No6embre 1918,
69622 Villeurbanne Cedex, France
c Laboratoire de Chimie de Coordination, CNRS, 205 route de Narbonne, 31077 Toulouse Cedex, France
Abstract
Cationic (p3-allyl) complexes of general formula [(p3-allyl)M(ligand)2]+Y−, where Y− is a non-coordinating anion (BF4−
,
ClO4−, BF4−) have been examined in telomerization reactions of buta-1,3-diene with representative nucleophiles. No reaction are
observed for nickel complexes, due to their high reactivity versus nucleophiles. With palladium complexes, the reaction only
occurs with alcohols and provides an increased selectivity for telomers with more than two diene units, leading to C16, C24 and
even higher ethers. Although much less reactive, platinum complexes can also produce higher telomers when hydrogenosilanes are
used. It is proposed, at least in the case of palladium, that the formation of C16 and C24 ethers arises from the coupling of C8 units
within dimeric palladium intermediates with the telogen acting as a bridging ligand. © 1998 Elsevier Science S.A. All rights
reserved.
Keywords: Buta-1,3-diene telomerization; Allyl complexes; Functionalized hexadecatetraenes; Palladium; Platinum
1. Introduction
The reaction is known to proceed smoothly with
group 10 metals. Neutral (p3-allyl) palladium com-
plexes have been reported to be catalyst precursors or
reaction intermediates in the catalytic transformation
of unsaturated substrates [5]. It has been also recog-
nized that cationic (p3-allyl) metal species may play a
central role in such reactions, although they are not
used as such as catalyst precursors [6]. Also, our ap-
proach to new catalytic reactions of unsaturated hy-
drocarbons was to design ad hoc cationic (p3-allyl)
complexes and to examine their activity in telomeriza-
tion reactions. For these precursors, one can predict:
(i) an easier coordination of substrates and reactants
via dissociation of labile ligands L; (ii) an increased
activity of donor substrates owing to the greater elec-
trophilic character of the metal center; and (iii) the
occurrence of reactions specific to the mono-
hapto?trihapto and masked hydride behaviors of the
allyl ligand [7].
Telomerization reactions of dienes are reported to
provide, in good yields, linear dimerization products
with a 1,6 or 3,6 addition of the telogen which is
generally a compound with active hydrogen (e.g. water
[1], alcohols [2], amines [3], carboxylic acids [4], etc.)
(Eq. (1)).
* Corresponding author. Present address: Institut de Recherches
sur la Catalyse, 2 avenue Albert Einstein, 69626 Villeurbanne Cedex,
France. Tel.: +33 561556270; fax: +33 561251733; e-mail: ig-
ort@dr7.cnrs.fr
0022-328X/98/$ - see front matter © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00789-X

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F. Bouachir et al. / Journal of Organometallic Chemistry 569 (1998) 203–215
(B3%) of 1-methoxy adducts were detected. Catalytic
activity and product selectivities are not modified by
the use of other cationic allylpalladium complexes or
their generation in situ.
We have already reported on efficient and economic
methods for the synthesis of cationic (p3-allyl) com-
plexes of nickel [8], palladium [9] and platinum [10]
using the general reaction between allyloxyphospho-
nium salts like 3 with the corresponding molecular
group 10 zerovalent precursors 4–6 (Eq. (2)).
Several parameters have a drastic influence on buta-
1,3-diene conversion and product distributions. As
shown in Table 1, conversions are always higher than
90% in the solvents examined except for acetonitrile
which inhibits the reaction. The highest yield of
C16OMe is observed when toluene is used. However, no
correlation can be found with any solvent parameter.
Reagent ratios, temperature and reaction time have a
greater influence on conversion and selectivity. As ex-
pected, an increase of the molar ratio MeOH/C4H6
leads to a greater selectivity in C8OMe ethers (Table 2).
It is noteworthy that the highest selectivity for C16OMe
ethers is not observed for the ratio MeOH/C4H6=1/4
but around 1/2. Interestingly, 1-methoxyhexadecate-
traene is build in noticeable amounts as the methanol
content in the reaction medium increases. An increase
in the reaction temperature allows a higher conversion
of buta-1,3-diene but at the expense of the telomers.
Fig. 1 indicates a steady decrease of the ethers C8OMe,
but optimal temperature for the formation of the higher
ethers C16OMe and C24OMe. Octatrienes and hexade-
capentaenes are not formed at the expense of the
telomers. Finally, reaction time has a drastic influence
on the product distribution. As shown in Fig. 2, the
highest selectivities are observed at the shortest time,
hence at the lowest buta-1,3-diene conversions. Fur-
thermore, C8OMe ethers selectivities slightly decrease
with increased reaction times. The yield of C16OMe and
C24OMe ethers reaches a plateau after 4 h. At longer
reaction times, large amounts of higher oligomers are
produced.
In this paper we present examples of unexpected
transformations of mixtures of buta-1,3-diene and ac-
tive hydrogen compounds (i.e. alcohols, amines, water
and silanes) and provide relevant mechanistic insights
on the formation of these compounds. A preliminary
account of part of this work has been published [11].
2. Results and discussion
2.1. Nickel complexes
Complexes 7 are catalysts for the oligomerization of
buta-1,3-diene [12]. The strong electrophilic character
of the nickel center enhances its reactivity toward nu-
cleophiles ([8]a). This could be extended to the p3-allyl
ligand. However, reaction of buta-1,3-diene with
methanol or diethylamine leads to low conversions of
the diene and to the decomposition of the complex used
(e.g. 7a, 7f) to Ni2+salts: the catalytic behavior of these
compounds was therefore not studied further.
The catalytic reaction observed with methanol pro-
ceeds well with other aliphatic alcohols and with phe-
nol. Table 3 sums up typical examples. Chemical
2.2. Palladium complexes
In the case of alcohols it is known that octadienyl
ethers are the main reaction products together with
octatrienes [2]. In very few instances higher telomers
containing three or four buta-1,3-diene units were ob-
served [13]. By reacting buta-1,3-diene with methanol in
the presence of complex 8c or 8d dissolved in
dichloromethane, a mixture of H(C4H6)nOMe ethers is
formed instead (Table 1). Noteworthy are the preferred
formation of C16 telomers and the presence as minor
components of telomers with an odd number of taxo-
gen units. The telomers with 2 (C8OMe), 4 (C16OMe),
and 6 (C24OMe) buta-1,3-diene units were characterized
by conventional spectroscopic techniques and hydro-
genation followed by comparison with authentic sam-
ples (Section 4). Thus, 1-methoxy-2,7-octadiene 1a,
3-methoxy-1,6,10,15-hexadecateraene
methoxy-1,6,10,14,18,23-tetracosahexaene 10a were
identified: for the higher telomers, only small amounts
9a
and
3-
Fig. 1. Influence of the reaction temperature on buta-1,3-diene con-
version and ether distributions (reaction conditions: [Pd]=0.25
mmol, C4H6=300 mmol, CH2Cl2=10 ml, reaction time=20 h).

F. Bouachir et al. / Journal of Organometallic Chemistry 569 (1998) 203–215
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F. Bouachir et al. / Journal of Organometallic Chemistry 569 (1998) 203–215
207
Fig. 2. Influence of the reaction time on buta-1,3-diene conversion and ether distributions (reaction conditions: [Pd]=0.25 mmol, C4H6=300
mmol, CH2Cl2=10 ml, temperature=80°C).
ionization mass spectra, 1H-NMR spectra and compari-
son of the hydrogenated products with the correspond-
ing saturated C4nOR ethers were used to ascertain the
structures. Inspection of Table 3 shows the expected
decrease in buta-1,3-diene conversion which was ac-
counted for by the increase in the steric hindrance of
the alkyl group [1]: MeꢀEt\i-Pr ꢁt-Bu. However,
1-t-butyloctadienylether which is not obtained with
conventional catalysts according to the literature [14] is
now produced in noticeable amounts. The high reactiv-
branched hydrocarbons with twice the number of car-
bon atoms (Eq. (3)) [15].
The telomers are smoothly converted into the corre-
sponding esters by carbonylation. It is noteworthy that
in the case of the 3-MeOC16 ether, the carbonylation
reaction gives rise to the 1-MeO(O)CC16 ester (Eq. (4))
[16].
ity of phenol is in agreement with published results, but
the poor reactivity of allyl alcohol requires further
investigation. Higher telomers are produced except for
t-butanol and allyl alcohol. It is worth noting that large
amounts of C12OPh ether are obtained: this may reflect
another mechanistic route to this compound.
However, one-pot synthesis of this compound start-
ing from buta-1,3-diene, methanol and carbon monox-
ide could not be achieved. In fact, the first step,
telomerization, requires an ionic complex and the sec-
ond step, carbonylation, occurs only in the presence of
chloride ions [17].
In the case of other telogens like secondary amines
and carboxylic acids, the catalytic reaction does not run
in the same way. Only octadienyl amines or esters were
obtained. With diethylamine, the product of nucle-
ophilic attack on the (p3-allyl) ligand of 8d is detected.
With acetic acid, dodecatetraenes are also formed. In
fact, complex 8d is converted into bis[(p3-methyl-2-al-
lyl)acetatopalladium] which is known for converting
buta-1,3-diene into C8 and C12 oligomers ([12]a).
Transformations of the telomers into other products
will provide new entries to long-chain unsaturated com-
pounds. The presence of an allyl function offers several
opportunities like dimerization and carbonylation. Re-
action of the telomers with acetic acid in the presence
of palladium acetate gives rise to unsaturated linear and
Addition of two equivalents of phosphane ligands to
the catalytic system formed in situ or the use of well
defined complexes like 8f and 8g gives rise to telomers
1
and, mostly, oligomers (Table 4). H-NMR analysis of
the reaction products indicates that compounds with
more than two buta-1,3-diene units are methoxy-1
telomers which exhibit branching in the oligomeric
chain since two vinyl groups are present (see Section 4).
Hydrogenation of these telomers confirms the occur-
rence of branching with one ethyl group. For the C16
telomer, analysis of the CI-MS spectra indicates that
the backbone of this compound corresponds to 1-
methoxy-6-ethyltetradecane, therefore suggesting struc-
ture 11 or 12.

F. Bouachir et al. / Journal of Organometallic Chemistry 569 (1998) 203–215
209

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F. Bouachir et al. / Journal of Organometallic Chemistry 569 (1998) 203–215
Other equilibria can take place, like: (i) the depro-
(ii) Reaction of 1,3,6- and 1,3,7-octatrienes with
tonation of one or both methanol ligands leading to a
less charged species (i.e. 19a); further dimerization can
be possible at that stage; and (ii) the coordination of
the pendent double bond of an octatrienyl ligand to
the other palladium center leading to a new type of
dimer (i.e. 18b).
Carbon–carbon coupling is possible with complex
18b, leading to the intermediate 20 which, through
i-elimination evolves the hexadecatetraenyl ligand 21.
Methanol (or methoxy ligand) is suitably well posi-
tioned in this complex for a nucleophilic attack at C-3
position of the p3-allyl ligand, therefore producing the
expected telomer. Interaction of 21 with an octatrienyl
species 17b will provide the route to the formation of
C24OMe telomers.
This mechanistic proposal requires two equivalents
of methanol for four moles of buta-1,3-diene, in
complete agreement with the experimental observa-
tion of highest C16OMe selectivity for a MeOH/C4H6
ratio of 1/2. The formation of the 1-methoxy isomer
by increasing the methanol amount will be explained
by external attack of the solvent at the less hindered
C-1 position. This proposal also explains the lack of
formation of t-BuOC16 ethers owing to the steric in-
hibition for dimerization. Finally, the low stability of
the reaction intermediates, especially the dimers, re-
quires low reaction temperatures and short reaction
times.
methanol in the presence of the same complex 8d
does not occur.
(iii) Reaction of 1-methoxyoct-2-ene (obtained by
selective hydrogenation of the terminal double bond
of 1-methoxyocta-2,7-diene in the presence of
Ru(PPh3)3Cl2 (see Section 4)) only provides, under the
same conditions as (i), small amounts of octa-1,3-di-
enes in addition to the starting compound.
We therefore suggest that the key step of the reac-
tion involves a coupling of two C8 units generated
from methoxy-1-octa-2,7-diene or methoxy-3-octa-1,7-
diene. These octadienyl ethers are formed either
through a zerovalent or a hydridopalladium species
(Eqs. (8) or (9)). The hydridopalladium could arise
from the reaction of the cationic (p3-allyl)palladium
complex with buta-1,3-diene (Eq. (8)) or from nucle-
ophilic attack of methanol on the allyl ligand (Eq.
(9)). The zerovalent palladium entity could be formed
by reductive elimination within the intermediate 16
resulting from deprotonation of methanol coordinated
to a cationic (p3-allyl)palladium species (Eq. (10)). It
should be pointed out that an equilibrium can occur
between the zerovalent palladium species and proton
and the cationic hydridopalladium species [20].
In the presence of phosphane ligands, the equi-
libria monomer dimer are not in favor of the latter
form(s). Hence, the amount of C8OMe ethers is
higher and the regioselectivity of the C–C coupling
is changed owing to the steric hindrance introduced
by the phosphane in the intermediate 22, analogous
to 18b. The C–C coupling now generates an inter-
mediate with a branched vinyl group (i.e. 23), where
the attack of methanol may occur on the terminal
carbon of the remaining p3-allyl ligand (Eq. (11)).
As already reported [17], a p3-octatrienyl unit is
formed by the attack of a zerovalent palladium spe-
cies on the protonated methoxyoctadiene. The corre-
sponding cationic (p3-allyl) complex 17a is solvated
with methanol and under the reaction conditions used
can be in equilibrium with a dimer 18a arising from
the formation of methanol bridges (Scheme 1).

F. Bouachir et al. / Journal of Organometallic Chemistry 569 (1998) 203–215
211
Scheme 1.
fore leading to a low concentration of cationic platinum
complexes which prevents the formation of dimeric
intermediates like 18.
2.3. Platinum complexes
Platinum precursors are much less active than palla-
dium ones in telomerization reactions of buta-1,3-diene
in the presence of ZH compounds. This trend is ob-
served too for cationic complexes like 9d. Moreover,
inspection of Table 5 shows that only methoxyoctadi-
enes are obtained in that case. Diethylamine also acts
as a telogen, giving diethyloctadienylamines.However,
the use of acetic acid does not lead to the formation of
acetoxyoctadienes. In fact 9d is converted into platinum
acetate which is inactive for this reaction under the
conditions used. Water also acts as a nucleophile but
only but-2-enol is produced with large amounts of C4n
oligomers in the presence of carbon dioxide. No adduct
is formed in the absence of carbon dioxide which is not
used under supercritical conditions. The absence of
higher telomers could be explained by a faster attack of
the alcohol molecule on the p3-allyl ligand of 17 there-
Platinum compounds are well known as catalysts for
hydrosilylation [21] and its use for the telomerization of
buta-1,3-diene with hydrogenosilanes as been reported
([22]a). In the present case, C4, C8 and C16 adducts are
obtained in the presence of triethylsilane (Table 5). No
C12 adducts are observed.If the reaction is performed in
the presence of triphenylphosphane, only the C4 ad-
ducts (cis and trans) are observed. The products were
identified by MS and NMR, and by comparison of the
hydrogenated derivatives with authentic samples pre-
pared by the conventional hydrosilation route: no
branched telomers are formed in this case. The C4
adduct are presumably formed by the 1,4 addition of
triethylsilane on buta-1,3-diene catalyzed by a cationic
platinum hydride complex generated according to the
process depicted in Eq. (8). The formation of the higher

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F. Bouachir et al. / Journal of Organometallic Chemistry 569 (1998) 203–215
Table 5
Telomerization of buta-1,3-diene with different telogens in the presence of platinum complexes
Run
Complex
Z–H
Conversion (%)
C4H6
Selectivity (%)
1-ZC4
1-ZC8
1-ZC16
C8
41
42
43
44
45
46
9d
9d
9d
9d
MeOH
AcOH
Et2NH
H2Oa
Et3SiH
Et3SiH
70
0
40
10
83
92
0
—
0
5
76
96
92
—
89
0
15
B1
0
—
0
0
9
8
—
11
95
B1
3
9d
9d+1PPh3
0
Reaction conditions: [Pt]=0.25 mmol, C4H6=300 mmol, ZH=75 mmol, CH2Cl2=10 ml, temperature=80°C (except run 45, 25°C), reaction
time=24 h.
a Under pressure of CO2 (20 bar).
telomers should proceed via another pathway than that
proposed in Scheme 1. Indeed, inspection of NMR
spectra indicates that there are no vinyl groups in the
C8 and C16 telomers formed with triethylsilane. A step-
wise addition process of one C4 (Et3SiC8) and one C8
unit (Et3SiC16) will be in agreement with the observa-
tions reported in the literature ([22]b). However, no C12
telomers are observed. Further work is needed for
understanding this specific reaction.
literature. Buta-1,3-diene was dried on Molecular Sieves
3A before use. Alcohols were distilled over the corre-
sponding alcoholates (methanol, ethanol, i-propanol)
or calcium hydride (t-BuOH). The phosphorus ligands
were either crystallized (triphenylphosphane, tricyclo-
hexylphosphane) or distilled under reduced pressure
(triphenylphosphite, tributylphosphane).
4.2. Syntheses
Zerovalent palladium complexes, allyloxytris(dimeth-
ylamino)phosphonium salts 3 and complexes 7, 8 and 9
were prepared according to the literature [8–10].
Authentic samples of the following C8 telomers with
alcohols were prepared for GC, MS and NMR com-
parison: 1-methoxyocta-2,7-octadiene ([22]a), 1-ethoxy
octa-2,7-octadiene [14], 1-i-propoxy octa-2,7-octadiene
[14], 1-phenoxyocta-2,7-octadiene [24], 1-methoxyoct-2-
ene is prepared by selective hydrogenation of 1-
methoxy-2,7-octadiene in the presence of Ru(PPh3)3Cl2
[25].
3. Conclusions
The isoleptic cationic (p3-allyl)metal complexes of the
nickel group exhibit very differentiated behavior in
telomerization reactions of buta-1,3-diene with different
types of telogens. Due to their electrophilic nature,
nickel complexes are transformed into Ni2+species
which are inactive in catalysis. The palladium com-
plexes are also sensitive to telogens like amines, water
and carboxylic acids. However the use of alcohols
provide an access to higher telomers with four, six, and
certainly higher even numbers of buta-1,3-diene units.
The formation of these new telomers can be explained
by the coupling of two C8 units (C16 telomers), one C16
and one C8 unit (C24 telomers), etc. within binuclear
palladium complexes with alcohol or alkoxy bridges.
Finally, the peculiar behavior of the platinum com-
plexes for telomerization of buta-1,3-diene with triethyl-
silane may arise from another process than that
depicted for palladium and protic solvents. Further
work on catalytic formation of higher functionalized
buta-1,3-diene oligomers is in progress [23].
4.3. Characterization of the higher telomers
4.3.1. 3-Methoxyhexadecatetraene
The reaction mixture (10 g) from repetitions of run 9
was percolated through a column of Kieselgel 60
(Merck) and then submitted to a first distillation (1
torr) leading to a distillate (7.2 g) containing octa-1,3,7-
triene, 1-methoxy-octa-2,7-diene and 3-methoxy-octa-
1,7-diene. The residue is distilled under 10−2 torr to
give fractions enriched (\95%) in 3-methoxyhexade-
catetraene (Eb 55–60°C, 1.5 g) and 3-methoxytetra-
cosahexadecatetraene (Eb 155–160°C, 0.7 g).
’
’
MS (EI, 70 eV): 248 (0.5, M+ ), 216 (0.6, M+
−
CH3OH), 107 (43, C8H1+1 ), 93 (14, C7H9+), 79 (86,
C6H7+), 71 (100, C4H7O+), 67 (61, C5H7+), 55 (31,
C4H7+), 45 (7, C2H5O+), 41 (64, C3H5+).
4. Experimental
4.1. General
IR (KBr): 1640 (wCꢀC), 1100 (wC–O, ether), 990 and
920 (lC–H, terminal vinyl), 970 cm−1 (lC–H, trans-dis-
ubstituted double bond).
Schlenk tube technique was used with purified argon
as inert gas. Solvents were distilled according to the

F. Bouachir et al. / Journal of Organometallic Chemistry 569 (1998) 203–215
213
NMR (80 MHz, CDCl3): l 1.3–1.7 (m, 4H), 1.8–2.3
(m, 10H), 3.30 (s, 3H), 3.55 (q, J=6 Hz, 1H), 4.9–6.0
C6H7+), 71 (20, C4H7O+), 67 (100, C5H7+), 55 (54,
C4H7+), 45 (39, C2H5O+), 41 (43, C3H5+).
3
ppm (m, 10H).
IR (KBr): 1640 (wCꢀC), 1120–1100 (wC–O, ether), 990
and 910 (lC–H, terminal vinyl), 970 cm−1 (lC–H, trans-
disubstituted double bond).
NMR (80 MHz, CDCl3): l 1.20–1.70 (m, 4H), 1.90–
2.25 (m, 9H), 3.32 (s, 3H), 3.85 (d, 3J=4 Hz, 2H),
4.8–5.1 (m, 4H), 5.3–6.0 ppm (m, 6H).
This product is hydrogenated (20 bar, 25°C) with
PtO2 (0.02 g) in pentane (25 ml). The retention time
(GC) and MS spectra of the hydrogenated product are
identical to those of 3-methoxyhexadecane.
IR (KBr): 1095 cm−1(wC–O, ether).
NMR (80 MHz, CDCl3): l 0.8–1.0 (m, 6H), 1.1–1.6
(m, 26H), 3.05 (q, J=5 Hz, 1H), 3.30 (s, 3H) ppm.
This product is hydrogenated (20 bar, 25°C) with
PtO2 (0.02 g) in pentane (25 ml). The retention time
(GC) and MS spectra of the hydrogenated product are
different from those of 1-methoxyhexadecane.
MS (m/z, CI, NH3): 274 (100, M+NH4+), 255 (46,
MH+), 148 (99, M−C9H19+NH4+), 111 (13, C8H1+5 ),
101 (20, C5H10OCH3+), 71 (C4H7O+), 58 (C3H6O+),
45 (C2H5O+).
3
4.3.2. 3-Methoxytetracosahexadecatetraene
’
MS (EI, 70 eV): 324 (1.8, M+ −CH3OH), 107 (45,
C8H1+1 ), 93 (20, C7H9+), 79 (71, C6H7+), 71 (52,
C4H7O+), 67 (70, C5H7+), 55 (30, C4H7+), 45 (4,
C2H5O+), 41 (41, C3H5+).
IR (KBr): 1640 (wCꢀC), 1090–1100 (wC–O, ether), 990
and 915 (lC–H, terminal vinyl), 970 cm−1 (lC–H, trans-
disubstituted double bond).
4.3.5. Telomers with ethanol
The reaction mixture from run 27 was percolated
through a column of Kieselgel 60 (Merck).
GC-MS (m/z, CI with NH3). For 1-EtOC8: 172 (100,
M+NH4+), 126 (11, M−EtOH+NH4+), 109 (32,
NMR (80 MHz, CDCl3): l 1.3–1.7 (m, 4H), 1.9–2.2
3
(m, 18H), 3.25 (s, 3H), 3.50 (q, J=7 Hz, 1H), 4.8–5.9
ppm (m, 14H).
M
+ −EtO). For 1-EtOC16: 280 (100, M+NH4+), 217
4.3.3. 1-Methoxyhexadecatetraene
(10, M+ −EtO). For 3-EtOC16: 280 (100, M+NH4+),
234 (3, M−EtOH+NH4+), 217 (64, M+ −EtO). For
3-EtOC24: 388 (100, M+NH4+), 325 (60, M+ −EtO).
Distillation of the reaction mixture from run 27 gives
a fraction containing 1-ethoxy-octa-2,7 diene and 3-
ethoxy-octa-1,7-diene (80:20, 0.2 g) and a fraction of
C16 compounds which is separated on a column of
Kieselgel 60 (Merck) with cyclohexane-ethyl acetate
(98:2) into three fractions: C16 (0.04 g), C16+EtOC16
(0.41 g) and 1-EtOC16+3-EtOC16 (20:80, 0.25 g) which
were examined by IR and NMR.
A fraction enriched in 1-methoxyhexadecatetraene is
obtained through chromatography of Kieselgel 60
(Merck), starting from a mixture of 1-MeOC16, 3-
MeOC16 and C16 (respectively, 15, 55 and 30% based on
GC analysis, 1 g). Elution with cyclohexane–ethyl ac-
etate (95:5) provides C16 (0.1 g), a mixture of the three
components (0.6 g) and a mixture of 1-MeOC16 and
3-MeOC16 (80:20, 0.25 g).
’
’
MS (EI, 70 eV): 248 (0.4, M+ ), 216 (0.7, M+
−
CH3OH), 107 (28, C8H1+1 ), 93 (27, C7H9+), 79 (51,
C6H7+), 71 (20, C4H7O+),67 (100, C5H7+), 55 (60,
C4H7+), 45 (29, C2H5O+), 41 (38, C3H5+).
IR (KBr): 1640 (wCꢀC), 1100 (wC–O, ether), 990 and
920 (lC–H, terminal vinyl), 970 cm−1 (lC−H, trans-dis-
ubstituted double bond).
IR (KBr): 1640 (wCꢀC), 1100 (wC–O, ether), 1000 and
910 (lC–H, terminal vinyl), 970 cm−1 (lC–H, trans-dis-
ubstituted double bond).
NMR (80 MHz, CDCl3): l 1.00–1.75 (m, ca. 3.5H),
3
1.55 (t, J=7 Hz, ca. 3H), 1.80–2.40 (m, ca. 10.5H),
3
NMR (80 MHz, CDCl3): l 1.2–1.8 (m, 4H), 1.8–2.2
3.00–3.70 (m, ca. 3H), 3.85 (d, J=4 Hz, ca. 0.5H),
3
(m, 10H), 3.25 (s, 3H), 3.80 (D, J=4 Hz, 2H), 4.8–6.0
4.80–6.00 ppm (m, ca.10H).
ppm (m, 9H).
4.3.6. Telomers with i-propanol
4.3.4. 1-Methoxy-6-6inyltetradecatriene
The reaction mixture from run 28 was percolated
through a column of Kieselgel 60 (Merck).
The reaction mixture (10 g) from repetitions of run
34 was percolated through a column of Kieselgel 60
(Merck) and then submitted to a first distillation (1
torr) leading to a distillate (8.5 g) containing octa-1,3,7-
triene, 1-methoxy-octa-2,7-diene and methoxy-3-hex-
adecatetraene as identified by GC. A fraction of this
distillate (3.7 g) is submitted to a second distillation (1
torr) leading to a residue (Eb 125–130°C, 0.5 g) which
contains mainly 1-methoxy-6-vinyltetradecatriene (\
GC-MS (m/z, CI with NH3). For 1-i-PrO–C8: 186
(100, M+NH4+), 126 (58, M−i-PrOH+NH4+),109
(98, M+ −i-PrO). For 1-i-PrO–C16: 294 (100, M+
NH4+), 234 (5, M−i-PrOH+NH4+), 217(67, M+ −i-
PrO). For 3-i-PrO–C16: 294 (20, M+NH4+), 234 (5,
M−i-PrOH+NH4+), 217(100, M+ −i-PrO). For 3-i-
PrO–C24: 402 (32, M+NH4+), 325 (100, M+ −i-PrO).
Distillation (1 torr) of part of the reaction mixture
from run 28 gives a fraction containing 1-i-propoxy-
octa-2,7 diene (Eb 30–35°C, 0.5 g) and a fraction of
C16 compounds (Eb 100–106°C) which is separated on
98%).
’
MS (EI, 70 eV): 216 (0.4, M+ −CH3OH), 107 (26,
C8H1+1 ), 93 (27, C7H9+), 85 (28, C5H9O+), 79 (49,

214
F. Bouachir et al. / Journal of Organometallic Chemistry 569 (1998) 203–215
a column of Kieselgel 60 (Merck) with cyclohexane,
then cyclohexane–ethyl acetate (98:2) into two frac-
tions: C16 (0.1 g) and 1-i-PrOC16+3-i-PrOC16 (30:70,
0.65 g) which were examined by IR and NMR.
(1 torr, Eb 42–45°C, 9.7 g) corresponds to a mixture of
cis- and trans-triethylsilylbut-2-ene (55:45).
MS (m/z, EI, 70 eV): 170 (39, M+ ), 144 (77,
’
C4H7SiEt2+), 115 (100, Et3Si+), 85 (47, C4H7SiH2+), 55
IR (KBr): 1640 (wCꢀC), 1120 and 1150 (wC–O, ether),
(8, C4H7+).
990 and 910 (lC–H, terminal vinyl), 970 cm−1 (lC−H
,
IR (KBr): 1646 (wCꢀC cis isomer), 1660 (wCꢀC trans
isomer), 960 (lC–C cis isomer), 750 (lC–C, trans isomer).
NMR (250 MHz, CDCl3): 0.55 (m, 6H), 0.94 (m,
9H), 1.37–1.65 (m, 2H), 1.55 (m, 3H), 5.35 ppm (m,
2H).
trans-disubstituted double bond).
NMR (80 MHz, CDCl3): l 1.15 (d, J=7 Hz, ca.
3
6H), 1.25–1.70 (m, ca. 3.5H), 1.80–2.30 (m, ca. 11H),
3
3
3.40–3.80 (heptuplet, J=6 Hz, ca. 2H), 3.85 (d, J=
6Hz, ca. 0.5H), 4.80–6.00 ppm (m, ca.10H).
The second fraction (10−2 torr, Eb 85–90°C, 1.6 g)
mostly contains 1-triethylsilylocta-2,7-diene (\95%).
MS (m/z, EI, 70 eV): 224 (2.5, M+ ), 195 (6,
’
4.3.7. Telomers with t-butanol
The reaction mixture from run 29 was percolated
through a column of Kieselgel 60 (Merck).
GC-MS (m/z, CI with NH3): 200 (14, M+NH4+),
126 (17, M−t-BuOH+NH4+),109 (100, M+ −t-
BuO).
C8H12SiEt2+), 169 (17, C4H6SiEt3+), 115 (74, Et3Si+),
108 (10, C8H1+2 ), 87 (100, HEt2Si+), 59 (38, H2EtSi+),
55 (3, C4H7).
NMR (250 MHz, CDCl3): 0.56 (m, 6H), 0.94 (m,
9H), 1.43–1.65 (m, 2H), 2.03 (m, 3H), 5.34 ppm (m,
8H).
4.3.8. Telomers with allyl alcohol
The third fraction (10−2 torr, Eb 160–175°C, 0.3 g)
mostly contains 1-triethylsilylhexadecatetraene (\
95%).
The reaction mixture from run 30 was percolated
through a column of Kieselgel 60 (Merck) and distilled
under reduced pressure (1 torr). The telomer recovered
MS (m/z, EI, 70 eV): 223 (1, C8H12SiEt3+), 169 (1.5,
C4H6SiEt3+), 163 (10.5, C12H19), 115 (100, Et3Si+), 87
(77, HEt2Si+),83 (2, C4H7Si+), 55 (2, C4H7).
NMR (250 MHz, CDCl3): 0.54 (m, 6H), 0.94 (m,
9H), 1.43–1.65 (m), 2.1 (m), 5.45–5.26 ppm (m).
(Eb 36°C, 0.1g) was examined by MS, IR and NMR.
MS (EI, 70 eV): 166 (0.1, M+ ), 57 (10, C3H5O ), 41
+
’
(41, C3H5+).
IR (KBr): 1640 (wCꢀC), 1060 (wC–O, ether), 990 and
910 (lC–H, terminal vinyl), 970 cm−1 (lC–H, trans-dis-
ubstituted double bond).
4.4. Catalytic runs
NMR (80 MHz, CDCl3): l 1.2 (s, 9H), 1.30–1.70 (m,
3
2H), 1.80–2.20 (m, 4H), 3.80 (d, J=4 Hz, 2H), 4.80–
All catalytic runs are performed in a 100 ml glass-
lined stainless steel autoclave equipped with a double
mantle for oil circulation and a magnet bar. The cover
of the autoclave is supplied with three valves for,
respectively, introduction of gases, introduction of liq-
uids (ball valve) and sampling, a manometer (0–50 bar)
and a safety valve adjusted to 50 bar.
For catalyst precursors prepared ex situ, the appro-
priate amount of cationic (p3-allyl) complex is placed
under argon in the autoclave which is tightly closed and
submitted to three vacuum–argon cycles. The appropri-
ate volume of solvent is then introduced with a glass
syringe, with eventually the dissolved phosphane, and
the mixture is agitated for 5 min. The autoclave is
cooled down to −10°C. The telogen is introduced with
a glass syringe and then the corresponding amount of
buta-1,3-diene is distilled from a calibrated thick-wall
glass bottle. The autoclave is connected to an oil-circu-
lating bath and heated at a given temperature for the
given time. Slow degassing allows the determination of
the buta-1,3-diene consumed during the reaction. The
autoclave is opened and the reaction mixture is pro-
cessed as indicated above.
5.10 (m, 2H), 5.40–6.00 ppm (m, 3H).
4.3.9. Telomers with phenol
The reaction mixture from run 31 was percolated
through a column of Kieselgel 60 (Merck).
GC-MS (m/z, EI, 70 eV). For 1-PhO–C8: 202 (6,
M+ ), 94 (100, PhOH ), 77 (10, C6H5 ). For 3-PhO–
+
+
’
C8: 202 (6, M+ ), 94 (62, PhOH+.), 77 (20, C6H5+).
’
For 1-PhO–C12: 256 (5, M+ ), 94 (92, PhOH ), 77
+
’
(23, C6H5+). For1-PhO–C16: 310 (3, M+ ), 94 (43,
’
PhOH+), 77 (15, C6H5+).
Distillation under reduced pressure (1 torr) gives
1-phenoxyocta-2,7-diene (Eb 85°C, 0.2g) which was
examined by GC, IR and NMR.
IR (KBr): 1640 (wCꢀC), 1600 and 1500 (wCꢀC), 1230
(wC–O, ether), 990 and 910 (lC–H, terminal vinyl), 970
(lC–H, trans-disubstituted double bond), 750 and 690
cm−1 (lC–H, phenyl).
NMR (80 MHz, CDCl3): l 1.3–1.7 (m, 2H), 1.80–
2.20 (m, 4H), 4.40 (d, J=4 Hz, 2H), 4.85–5.15 (m,
2H), 5.40–6.00 (m, 3H), 6.7–7.4 ppm (m, 5H).
3
4.3.10. Telomers with triethylsilane
For catalyst precursors prepared in situ, the appro-
priate amounts of palladium complex and allyloxytris-
(dimethylamino)phosphonium salt are placed under
The reaction mixture from run 45 is distilled under
reduced pressure (1, then 10−2 torr). The first fraction

F. Bouachir et al. / Journal of Organometallic Chemistry 569 (1998) 203–215
215
[3] G.P. Chiusoli, M. Costa, L. Pallini, G. Terenghi, Transition
Metal Chem. 7 (1982) 304.
[4] D. Rose, H. Lepper, J. Organometal. Chem. 49 (1973) 473.
[5] J. Tsuji, Organic Syntheses with Palladium Complexes, Springer,
Berlin, 1980.
[6] B.M. Trost, Tetrahedron 33 (1977) 2615.
[7] P.W. Jolly, G. Wilke, The Organic Chemistry of Nickel, vol. II,
Academic Press, New York, 1971, p. xxx.
[8] (a) D. Neibecker, B. Castro, J. Organometal. Chem. 134 (1977)
105. (b) Tetrahedron Lett. (1977) 2351. (c) Inorg. Chem. 19
(1980) 3725.
[9] P. Grenouillet, D. Neibecker, I. Tkatchenko, Inorg. Chem. 19
(1980) 3189.
[10] (a) F. Bouachir, Ph. D. Thesis, Universite´ Paul Sabatier, Tou-
louse, 1990. (b) F. Bouachir, D. Neibecker, J.-M. Savariault, I.
Tkatchenko, Inorg. Chem. (submitted).
argon in a Schlenk tube which is then submitted to
three vacuum–argon cycles. The corresponding volume
of solvent is then introduced with a glass syringe and
the mixture is agitated until a yellow solution is ob-
tained. Eventually the phosphane dissolved in a small
amount of solvent is added and the mixture agitated
during 5 min. The solution is removed with a glass
syringe and transferred to the autoclave.
In the case of telomerization of buta-1,3-diene with
water, after addition of the diene, the autoclave is
pressurized with carbon dioxide (20 bar, Air Liquide
N35).
4.5. Model reactions
[11] (a) P. Grenouillet, D. Neibecker, J. Poirier, I. Tkatchenko,
Angew. Chem. 94 (1982) 796. (b) Angew. Chem. Internat. Ed.
Engl. 21 (1982) 767.
[12] P. Grenouillet, D. Neibecker, I. Tkatchenko, J. Organometal.
Chem. 243 (1983) 213.
[13] (a) D. Medema, R. van Helden, Recl. Trav. Chim. Pays-Bas 90
(1971) 324. (b) Mitsubishi Chemical Industries Ltd., French
Demande 2 079 319 (1971). (c) Chem. Abstr. 76 (1972) 3388n.
[14] V.J. Beger, H. Reichel, J. Prakt. Chem. 315 (1973) 1067.
[15] D. Neibecker, J. Poirier, I. Tkatchenko (to be published).
[16] D. Neibecker, J. Poirier, I. Tkatchenko, J. Org. Chem. 54 (1989)
2459.
[17] (a) M.C. Bonnet, D. Neibecker, B. Stitou, I. Tkatchenko, J.
Organometal. Chem. 366 (1989) C9. (b) M.C. Bonnet, J.
Coombes, B. Manzano, D. Neibecker, I. Tkatchenko, J. Mol.
Catal. 52 (1989) 263.
4.5.1. Dimerization of methoxyoctadienes
In a Schlenk tube are added successively under ar-
gon: 8d (0.25 mmol, 108 mg), dichloromethane (5 ml),
methanol (5 ml) and a mixture of 1- and 3-methoxyoc-
tadienes (15:85, 100 mmol, 14 g). The mixture is
refluxed under argon for 4 h (precipitation of palla-
dium). The solvents are distilled off and the reaction
products are examined by GC which indicates: octa-
1,3,7-triene (6%), 1-MeOC8 (24%), 3-MeO-C8 (traces),
MeOC12 (2%), C16 (3%), 1-MeOC16 (2%), 3-MeOC16
(25%), MeOC20 (3%), MeOC24 (5%).
4.5.2. Reaction with 1-methoxyoct-2-ene
[18] P.M. Maitlis, The Organic Chemistry of Palladium, vol. II,
Academic Press, New York, 1971, p. 40.
In a Schlenk tube are added successively under ar-
gon: 8d (0.125 mmol, 54 mg), dichloromethane (2.5 ml),
methanol (2.5 ml) and 1-methoxyoct-2-ene (50 mmol, 7
g). The mixture is refluxed under argon for 4 h (precip-
itation of palladium). The solvents are distilled off and
the reaction products are examined by GC which only
shows the starting material with traces of octadienes.
[19] (a) P.W. Jolly, R. Mynott, B. Raspel, K.P. Schick, Organometal-
lics 5 (1986) 473. (b) A. Behr, G.W. Ilsemann, W. Keim, C.
Kru¨ger, Y.H. Tsay, Organometallics 5 (1986) 514.
[20] M.C. Bonnet, V. Miebach, I. Tkatchenko (submitted).
[21] B. Marcinec, in: B. Cornils, W. A. Herrmann (Eds.), Applied
Homogeneous Catalysis with Organometallic Compounds, vol.
1, VCH, Weinheim, 1996, p. 420.
[22] (a) S. Takahashi, Y. Yamazaki, N. Hagihara, Bull. Chem. Soc.
Japan 41 (1968) 254. (b) L. Langova, H. Hetflejs, Coll. Czech.
Chem. Commun. 40 (1975) 420.
References
[23] D. Neibecker, M. Touma, I. Tkatchenko, unpublished work.
[24] (a) E.J. Smutny, J. Am. Chem. Soc. 89 (1967) 6793. (b) H.
Chung, W. Keim, US Patent 3 636 162 (1972). (c) Chem. Abstr.
76 (1972) 85545.
[1] Y. Tokitoh, N. Yoshimura, US Pat. 4 808 756, Kuraray Co,
1989.
[2] W. Keim, A. Behr, M. Ro¨per, in: G.Wilkinson, F.G.A. Stone,
E.W. Abel (Eds), Comprehensive Organometallic Chemistry, vol.
8, Pergamon, Oxford, 1982, p. 430.
[25] J. Tsuji, H. Suzuki, Chem. Lett. (1977) 1083.
.

208
F. Bouachir et al. / Journal of Organometallic Chemistry 569 (1998) 203–215
Table 3
Telomerization of buta-1,3-diene with alcohols: influence of the nature of the telogen
Run ROH
Conversion (%)
C4H6
Yield (%)
Selectivity (%)
ROC8 ROC16 ROC24 1-ROC8 3-ROC8 ROC12 1-ROC16 3-ROC16 ROC20 ROC24 C8 C16
11
27
28
29
30
31
MeOH
EtOH
i-PrOH
t-BuOH 38
C3H5OH 45
94
94
79
19
9
18
7
4
21
32
20
14
—
—
11
8
8
4
—
—
—
19
11
22
17
10
20
1
B1
—
—
—
2
1
2
—
—
—
12
2
2
4
—
—
3
32
20
14
—
—
8
2
9
—
—
—
—
9
9
5
—
—
—
2
2
3
4
—
3
3
3
2
—
—
—
PhOH
97
Reaction conditions: [Pd]=0.25 mmol, C4H6=300 mmol, ROH=75 mmol, toluene=10 ml, temperature=80°C, reaction time=20 h.
higher oligomers of buta-1,3-diene are generated in a
second stage, after catalyst deactivation for telomeriza-
tion. The main pathway of palladium-catalyzed reac-
tion of buta-1,3-diene is dimerization. Trimerization to
form dodeca-1,3,6,10-tetraene takes place with the
dimeric complex 15 in the absence of phosphane lig-
ands ([13]a). Although tetramerization is even detected
with this compound, the results reported here show that
C8n linear chains coming from buta-1,3-diene are selec-
Two reaction pathways were proposed for the telom-
erization of buta-1,3-diene with alcohols [18]. The first
one involves oxidative coupling of two diene units
leading to a bis(p3-allyl) complex 13 (Eq. (5)).
The second one corresponds to stepwise addition of
two diene units on a hydridopalladium species, leading
to a (p1-allyl)palladium compound 14 (Eq. (6)).
tively formed. Thus, none of the active species pro-
posed in the literature gives satisfactory explanations
for the build-up of C16 and C24 chains.
The process depicted by Eq. (5) seems to be preferred
in the case of alcohols [19]. The greater C16OMe and
C24OMe selectivities observed at low conversion of
buta-1,3-diene indicate that the catalytic species able to
induce this reaction, does evolve during the early stages
of the process. Furthermore, the corresponding yields
are not modified after 4 h of reaction, suggesting that
Three experiments indicates the role of preformed C8
chains in the formation of these higher telomers:
(i) The reaction takes place with 1-methoxy-octa-2,7-
diene in the presence of 8d and a 1:1 mixture of
dichloromethane and methanol (Eq. (7)). A product
distribution typical of the telomerization described above
is achieved. The conversion is higher in the presence of
buta-1,3-diene which may stabilize the active species.