Palladium-catalyzed C-C bond formation: Synthesis of 1,1-dialkylbuta-1,3-dienes and β-phenylstyrenes via organoboron intermediates

Article abstract of DOI:10.1002/ejoc.200300136

α,β-Unsaturated and α-phenyl acetals show different reactivity when treated with LIC-KOR superbase and trialkylboranes, in the presence of the reagent system PdL₄-ArX (Suzuki-Miyaura cross-coupling conditions). In particular, unsaturated acetal

Full text of DOI:10.1002/ejoc.200300136

FULL PAPER
Palladium-Catalyzed C؊C Bond Formation: Synthesis of 1,1-Dialkylbuta-1,3-
dienes and β-Phenylstyrenes via Organoboron Intermediates[
‡]
[a]
[b]
[a]
[a]
Annamaria Deagostino, Cristina Prandi,* Chiara Zavattaro, and Paolo Venturello*
Keywords: Acetals / Superbases / Cross-coupling / Palladium / Boron
α,β-Unsaturated and α-phenyl acetals show different reac- an anionotropic alkyl migration; in the case of α-phenyl
tivity when treated with LIC-KOR superbase and trialkyl-
boranes, in the presence of the reagent system PdL -ArX
Suzuki−Miyaura cross-coupling conditions). In particular,
derivatives, the corresponding cross-coupling products are
recovered.
4
(
unsaturated acetals yield gem-dialkylbutadienes via the
( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
formation of an intermediate π-allyl complex that facilitates
Germany, 2003)
Introduction
LIC-KOR base: the excess reagent selectively deprotonates
the elimination product at the α-vinyl site, giving a nucle-
ophile that can be quenched with various electrophiles,
The SuzukiϪMiyaura palladium-catalyzed cross-coup-
ling reaction between organoboron compounds and organic
[
9]
yielding substitution or addition products. By resorting to
this procedure, we have described different functionalized
unsaturated systems, and various organostannane reagents
have been prepared in order to construct carbon-carbon
bonds by means of the Stille cross-coupling reaction.[
More recently, the reactivity of α-metalated alkoxy dienes
electrophiles provides a powerful method for the formation
of carbonϪcarbon bonds.[1] Consequently, organoboron re-
agents provide a versatile tool for the construction of more
complex molecules from a simple precursor. Moreover,
polyenic building blocks with fixed configuration appear to
be of importance for the synthesis of a dienic partner in the
10]
[
11]
[12]
in the presence of trialkylboranes or trialkylborates as
electrophiles has also been described.
[2]
DielsϪAlder cycloaddition reaction, for the production
[3]
of many bioactive compounds or of structures having
nonlinear optical properties[ or high conductivity.
4]
[5]
Results and Discussion
We have previously reported that in the presence of the
Schlosser’s superbase LIC-KOR[6] (LIC: butyllithium,
KOR: potassium tert-butoxide), α,β-unsaturated acetals
selectively yield 1-alkoxybuta-1,3-dienes.[ The product de-
rives from a stereoselective conjugate elimination that is in-
itiated by the metalation reaction at the γ-allylic position of
the unsaturated substrate. Similarly, under these experimen-
tal conditions 1,1-dimethoxy-2-phenylethane and 1,1-di-
methoxy-2-phenylpropane undergo a 1,2-elimination reac-
tion that gives methyl styryl ethers.[ Moreover, both buta-
dienyl and styryl derivatives can be further functionalized
at their α-position by conducting the former elimination re-
action in the presence of at least two equivalents of the
In this paper we report the new results of our attempts
to perform the LIC-KOR-promoted elimination, the func-
tionalization process, and the SuzukiϪMiyaura cross-coup-
ling reaction in a one-pot procedure. Indeed, we have con-
sidered the possibility of taking advantage of the basic me-
dium in which the elimination and functionalization steps
are conducted. This is because evidence exists that the coor-
dination of negatively charged bases to the boron atom is
an efficient way of increasing its nucleophilicity and transfer
of the organic group from the boron to the adjacent posi-
7]
8]
[13]
tive center. The obtained results are indeed different and
depend on the nature of the organometallic intermediate
Ϫ either a boron-functionalized alkoxy-diene or a boron-
functionalized alkoxy-styrene. In fact, when a THF solution
[
[
‡]
a]
Partially taken from the Laurea Thesis of C. Z.
Dipartimento di Chimica Generale ed Organica Applicata, of [Pd(PPh ) ] and iodobenzene was added to the basic re-
3
4
Universit a` di Torino,
action mixture in which the α-metalated 1,3-butadiene had
been previously treated with a trialkyborane, the only iso-
lated product was a 1,1-dialkylbuta-1,3-diene. Both the
alkyl substituents at the C(1) of the conjugate system come
from the alkylborane, according to a previously proposed
4
8, Corso M. D’Azeglio, 10125 Torino, Italy
Fax: (internat.) ϩ39-011-2367646
E-mail: paolo.venturello@unito.it
Dipartimento di Scienze e Tecnologie Avanzate, Universit a` del
Piemonte Orientale,
[
b]
33, Spalto Marengo, 15100 Alessandria, Italy
2612
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
DOI: 10.1002/ejoc.200300136
Eur. J. Org. Chem. 2003, 2612Ϫ2616

Palladium-Catalyzed CϪC Bond Formation
FULL PAPER
rearrangement.[11] On the other hand, the same synthetic yl)hexylborane (Entries 6 and 7) were used, the produced
sequence yields, in the case of phenylacetaldehyde and 2- butadienes were recovered as a mixture of (1E) and (1Z)
phenylpropionaldehyde dimethyl acetals, the corresponding 1,1-disubstituted isomers, along with 1,1-dicyclohexylbuta-
SuzukiϪMiyaura cross-coupling product. Different sym- 1,3-diene.
metric trialkylboranes of the BR3 type (Table 1, Entries
The crude product mixture of the reaction carried out
1
Ϫ5 and 8Ϫ14) and two mixed ones, with a BR RЈ struc- with (dicyclohexyl)octylborane does not contain 4-octyldo-
2
ture (Table 1, Entries 6 and 7) have been used, and the reac- decabuta-1,3-diene (4e), nor does that obtained with (di-
tion has been proven to be of wide applicability. Moreover, cyclohexyl)hexylborane show any trace of 4-hexyl-1,3-deca-
to the best of our knowledge, thus far there are no general diene (4c) (by GC analyses; comparison with authentic
methods for the synthesis of 1,1-dialkyl-substituted buta- samples). These results exclude any intermolecular contri-
[
14]
1
,3-dienes.
bution to the alkyl-transfer mechanism. Moreover, the ratio
between the obtained products [4-cyclohexyl-1,3-dodecadi-
ene (4f)/1,1-dicyclohexylbuta-1,3-diene (4d), 70:30; 4-cyclo-
Table 1. Reaction of acetals 1aϪ1d with different trialkylboranes
BR or BR RЈ): synthesis of 1,1-dialkylbutadienes 4aϪn
3 2
[
a]
(
hexyl-1,3-decadiene
(4g)/1,1-dicyclohexylbuta-1,3-diene
1
(4d), 70:30, by H NMR spectroscopy), which corresponds
Entry
Acetal
R
Product
Yields (%)
approximately to the statistically expected composition,
clearly excludes any significant difference in the migratory
aptitude of the alkyl groups.
1
2
3
4
5
6
7
8
9
1a
1a
1a
1a
1a
1a
1a
1b
1b
1b
1c
1c
1d
1d
C
4
H
9
4a
4b
4c
4d
4e
4f[
4g[
4h
4i
79
86
68
77
68
65
71
42
55
45
49
41
48
48
c-C
n-C
c-C
n-C
(c-C
(c-C
5
H
9
6
H
13
11
17
The proposed mechanism is shown in Scheme 2, the first
step (not represented) being the oxidative addition of iodo-
6
H
8
H
H
H
0
II
b]
6
11
)
)
2
/n-C
/n-C
8
H
H
17
benzene to Pd to form a Pd complex. The presence of
alkoxy groups (EtO and tBuO) in the reaction medium
could promote both the rearrangement of boron ‘‘ate’’ com-
plex 2 to give derivative 3 (see Scheme 1), and the formation
b]
6
11
2
6
11
C
4
H
9
c-C
c-C
5
H
9
1
1
1
1
1
0
1
2
3
4
6
H
11
4j
II
of the new Pd alkoxo complex B, by ligand exchange with
C
4
H
9
4k
4l
4m
4n
[
16]
II
c-C
5
H
9
C H -PdL -I (A), as shown in Scheme 3.
Either Pd
6
5
2
C
4
H
9
complex can interact with the borate complex 3 inducing
an anionotropic 1,2-shift of an alkyl group from boron to
the C(1) terminus of the dienic system. The mechanism
c-C
6
H
11
[
a]
First step: acetal (5.0 mmol), BuLi (12.5 mmol), tBuOK
(
12.5 mmol), trialkylborane (5.0 mmol), THF (10 mL), T ϭ Ϫ95 probably then proceeds through the following steps: i) for-
Ϫ2
to 25 °C; second step: ArI (4.0 mmol), [Pd(PPh
3 4
) ] (5.73 10 g, mation of a new π-allyl complex; ii) formation of a new
1
(
% molar with respect to the acetal), NaOH (1.0 , 3.0 mL), H O
2 2
boron ‘‘ate’’ complex, iii) final elimination reaction to give
the 1,1-disubstituted product (Scheme 2). A similar reaction
mechanism, involving an addition-elimination sequence
30 wt.%, 3.0 mL), T ϭ 25 °C. [ 1,1-Dicyclohexylbuta-1,3-diene
b]
has also been obtained.
Treatment of acetals 1aϪd at Ϫ95 °C with the LIC-KOR with the final elimination of XPdBY , has been invoked to
2
base and the appropriate trialkylborane readily gives the explain the formation of ‘‘head-to-tail’’ cross-coupling
[
17]
corresponding 1,1-dialkylbuta-1,3-diene in accordance with products.
the steps shown in Scheme 1.[
15]
Scheme 2
Scheme 1
As reported in Table 1, gem-dialkylbuta-1,3-dienes were
recovered in good yields: tributyl-, trihexyl-, trioctyl-, tricy-
clopentyl-, and tricyclohexylborane were used as electro-
philes. When (dicyclohexyl)octylborane and (dicyclohex- Scheme 3
Eur. J. Org. Chem. 2003, 2612Ϫ2616
www.eurjoc.org
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2613

A. Deagostino, C. Prandi, C. Zavattaro, P. Venturello
In order to investigate the role of the Pd catalyst and of Table 3. Reaction of acetals 5aϪb with tributylborane and Ar-X
FULL PAPER
3 4
iodobenzene in the formation of product 4, some additional in the presence of [Pd(PPh )] : synthesis of aryl-substituted styryl
derivatives 6aϪc
experiments have been carried out. In particular, the reac-
tion has also been performed in the absence of iodoben-
zene: in this case no alkyl-functionalized butadiene was de-
tected. On the other hand, in the presence of catalytic
Acetal
ArϪX
Product
Yields (%)[a]
5a
PhI
PhI
MeOPhI
6a
6b
6c
38
46
41
amounts of iodobenzene the dialkylated product has been 5b
obtained, although longer reaction times were required. 5b
II
The role of the Pd catalyst has been assessed by carrying
[
a]
First step: acetal (5.0 mmol), BuLi (12.5 mmol), tBuOK
12.5 mmol), trialkylborane (5.0 mmol), THF (10 mL), T ϭ Ϫ95
out the reaction in the presence of different Pd complexes.
The results obtained with the tested systems are reported in
Table 2. Good yields have been achieved using both 1% molar with respect to the acetal), NaOH (1.0 , 3.0 mL), H O
2 2
(
Ϫ2
3 4
to 25 °C; second step: ArϪI (4.0 mmol), [Pd(PPh ) ] (5.73 10 g,
(
30 wt.%, 3.0 mL), T ϭ 25 °C.
[
Pd(OAc) (PPh ) ] and [PdCl (CH CN) ] (Table 2, Entry 4
2 3 2 2 3 2
and 5, respectively), while Pd(OAc) turns out to be ineffec-
2
tive (Table 2, Entry 1); nevertheless, the addition of two
Furthermore, the data in Table 3 require some additional
equivalents of PPh (with respect to the Pd complex) to the
3
comments: in particular, the basic medium in which the
cross-coupling occurs seems to affect the reaction outcome
and to reduce the yields by promoting a further elimination
reaction on the cross-coupling product. 1,2-Diphenylethyne,
derived from the 1,2-elimination reaction of MeOH from
reaction mixture promotes the formation of the gem-di-
alkyl-substituted derivative (Table 2, Entry 2). These data
II
suggest that the reaction is efficiently catalyzed by Pd
complexes containing two equivalents of phosphane li-
gands, while an additional equivalent of phosphane tends
to slow down the reaction (Table 2, Entry 3). Using
1-methoxy-1,2-diphenylethene, was indeed detected in the
crude reaction mixture. This elimination reaction has pre-
viously been noticed and discussed for analogous sys-
[
(dichloro){1,1Ј-bis(diphenylphosphanyl)ferrocene}]-
palladium() [PdCl (dppf)] as a catalyst, the reaction occurs
2
[
18]
tems.
readily to give the gem-dialkyl-substituted derivative (En-
try 6).
In conclusion, we have devised a one-pot synthesis that,
starting from α,β-unsaturated and α-phenyl acetal, gives
1,1-dialkylbuta-1,3-dienes and 1-methoxy-2-phenylstyrenes,
respectively. A cascade of quaternization reactions and 1,2-
anionotropic rearrangements in the presence of an activated
Pd π-complex may account for the formation of 1,1-dialkyl-
butadienes; in the absence of the conjugated system, a
standard Suzuki cross-coupling reaction takes place. In the
first case the synthesis leads to products that are not readily
accessible by other methods; 1-alkoxy-2-phenylstyrenes are
isolated with yields that are poorer than those obtained
when stryrylboronates are isolated as stable intermedi-
Table 2. Reaction of acetals 1a with tributylborane and ArϪI in
the presence of different catalysts: synthesis of diene 4a
Entry[a]
Catalyst
Yields (%)
1
2
3
4
5
Pd(CH
Pd(CH
Pd(CH
Pd(CH
3
3
3
3
CO
CO
CO
CO
2
2
2
2
)
)
)
)
2
2
2
2
Ϫ
/(C
/(C
[(C
6
6
6
H
H
H
5
5
5
)
)
)
3
3
3
P (2.0 equiv.)
P (4.0 equiv.)
77
36
59
65
55
P]
2
PdCl
PdCl
2
(CH
(dppf)
3 2
CN)
[
b]
6
2
[12]
ates.
[
a]
First step: acetal (5.0 mmol), BuLi (12.5 mmol), tBuOK
12.5 mmol), trialkylborane (5.0 mmol), THF (10 mL), T ϭ Ϫ95
(
Ϫ2
to 25 °C; second step: ArϪI (4.0 mmol), [Pd(PPh
1
(
3
)
4
] (5.73 10 g, Experimental Section
% molar with respect to the acetal), NaOH (1.0 , 3.0 mL), H
O
2 2
30 wt.%, 3.0 mL), T ϭ 25 °C. [ Acetal 1b was used as a substrate.
b]
General Remarks: Flasks and all equipment used for the generation
and reaction of moisture-sensitive compounds were flame dried un-
der argon. Where a temperature of Ϫ95 °C is indicated a slush
bath of liquid nitrogen/acetone was used. THF was distilled from
benzophenone ketyl prior to use. BuLi (1.6  solution in hexanes)
Product 4h was recovered.
On the other hand, starting from α-phenyl acetals 5a and
5
b, in the presence of phenyl iodides, and [Pd(PPh )] as was obtained from Aldrich. tBuOK was sublimated in vacuo
3 4
a catalyst, 1,2-diaryl-substituted methoxyethenes have been (0.1 Torr) prior to use. Tributylborane (1.0  solution in THF) was
obtained, according to the SuzukiϪMiyura cross-coupling purchased from Aldrich; other trialkylboranes were synthesized ac-
cording to literature methods[ and used as a 1.0  solution in
19]
reaction. In particular, unsubstituted and substituted phe-
THF. All other commercially obtained reagents were used as re-
nyl iodides were used, and the results are outlined in Table 3
ceived. Products were purified by preparative column chromatogra-
and in Scheme 3. Some experiments were also carried out
in order to verify the influence of the organoboron deriva-
tive on the reaction outcome: tributyl- and tricyclopentyl-
borane were used, and no significant difference was de-
tected among the reactivity of the two organometallic re-
phy on Merck silica gel 60 with light petroleum ether (boiling range
0Ϫ60 °C)/diethyl ether as eluent. H NMR spectra were recorded
at 400 and 200 MHz in CDCl , using TMS as internal standard.
3
Coupling constants (J) are given in Hz and coupling patterns are
1
4
described by abbreviations: s (singlet), d (doublet), t (triplet), q
1
3
agents. The subsequent syntheses were thus carried out in (quadruplet), br. s (broad singlet). C NMR spectra are recorded
the presence of the commercially available tributylborane.
at 100.4 or 50.2 MHz in CDCl
3
, and chemical shifts are quoted
2614
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2003, 2612Ϫ2616

Palladium-Catalyzed CϪC Bond Formation
FULL PAPER
4-Octyldodecabuta-1,3-diene (4e): 0.94 g (68%) as a colorless oil. H
1
relative to the residual solvent peak (δ ϭ 77.0 ppm). GC-MS spec-
tra were measured with a mass-selective detector HP 5970 B instru-
3
NMR (400 MHz, CDCl ): δ ϭ 0.96 (t, J ϭ 7.1 Hz, 6 H), 1.21Ϫ1.35
ment operating at an ionizing voltage of 70 eV connected to a HP (m, 24 H), 1.94 (m, 2 H), 2.51 (m, 2 H), 5.01 (dd, J ϭ 10.0, 1.0
5
0
890 GC, cross-linked methyl silicone capillary column (25 m ϫ
.2 mm ϫ 0.33 µm film thickness).
Hz, 1 H), 5.1 (dd, J ϭ 16.0, 1.0 Hz, 1 H), 5.85 (d, J ϭ 10.0 Hz, 1
1
3
H), 6.78 (dt, J ϭ 16.0, 10.0 Hz, 1 H) ppm. C NMR (100.4 MHz,
CDCl ): δ ϭ 14.2, 14.4, 23.3, 23.4, 28.5, 30.2, 30.3, 30.6, 32.3, 32.4,
3
Typical Procedure for the Synthesis of 1,1-Dialkylbutadienes 4a؊n
and Styryl Derivatives 6a؊c: The acetal (5.0 mmol) and BuLi
32.6, 38.7, 116.1, 120.3, 138.4, 151.5 ppm. MS (EI, 70 eV): m/z (rel.
ϩ
int.) ϭ 278 (3) [M ], 249 (10), 221 (14), 179 (38), 41 (100). C H
38
2
0
(7.8 mL, 12.5 mmol) were added dropwise to a cooled (Ϫ95 °C)
(278.5): calcd. C 86.25, H 13.75; found C 86.95, H 13.95.
solution of tBuOK (1.4 g, 12.5 mmol) in anhydrous THF (10 mL).
After a few seconds the solution turned purple and was stirred at
Ϫ95 °C for 2 h; the appropriate trialkylborane (5.0 mL of a 1.0 
THF solution) was then added. After 2 h the temperature was
raised to room temp. for another 2 h. In the meantime, a THF
4
0
0
2
1
-Cyclohexyl-1,3-dodecadiene (4f): (Mixture of isomers E and Z).
.80 g (65%) as a colorless oil. H NMR (400 MHz, CDCl ): δ ϭ
3
1
.96 (t, J ϭ 6.9 Hz, 3 H), 1.33Ϫ1.76 (m, 22 H), 1.96 (t, J ϭ 6.0 Hz,
H), 2.15 (tt, J ϭ 10.6, 6.0 Hz, 1 H), 4.98 (dd, J ϭ 10.0, 1.0 Hz,
H), 5.10 (dd, J ϭ 16.0, 1.0 Hz, 1 H), 5.75 (d, J ϭ 10.0 Hz, 1 H),
(
(
3.0 mL) solution of C
5.73 10 g, 1% with respect to the acetal) was prepared in a three-
6
H
5
I (0.81 g, 4.0 mmol) and [Pd(PPh
3 4
)]
1
3
Ϫ2
6.70 (dt, J ϭ 16.0, 10.0 Hz, 1 H) ppm. C NMR (100.4 MHz,
CDCl ): δ ϭ 15.3, 23.6, 25.4, 25.7, 27.9, 28.2, 29.6, 29.8, 30.5, 30.7,
1.4, 31.8, 35.9, 36.2, 112.4, 119.2, 136.8, 140.7 ppm. MS (EI,
3
necked flask under argon. The reaction mixture was then added
dropwise under inert atmosphere to the [Pd(PPh )] /C I solution
and allowed to react for 8 h. It was then oxidized with 3.0 mL of
NaOH and 3.0 mL of H (30%). The mixture was then diluted
with Et O and washed with brine. After evaporation of the solvent
the crude isolated product was purified by column chromatography.
3
7
4
3
4
6 5
H
ϩ
0 eV): m/z (rel. int.) ϭ 248 (8) [M ], 165 (21), 150 (65), 94 (41),
1 (100). C18 32 (248.5): calcd. C 87.02, H 12.98; found C 87.05,
H
2
O
2
H 11.95.
2
4
0
0
-Cyclohexyl-1,3-decadiene (4g): (Mixture of isomers E and Z).
1
.48 g (53%) as a colorless oil. H NMR (400 MHz, CDCl
3
): δ ϭ
4
-Butylocta-1,3-diene (4a): 0.66 g, (79%) as a colorless oil. 1
NMR (400 MHz, CDCl ): δ ϭ 0.98 (t, J ϭ 7.0 Hz, 3 H), 1.01 (t,
J ϭ 7.0 Hz, 3 H), 1.32Ϫ1.37 (m, 8 H), 2.14 (t, J ϭ 7.0 Hz, 2 H),
.16 (t, J ϭ 7.0 Hz, 2 H), 4.97 (dd, J ϭ 10.0, 1.0 Hz, 1 H), 5.1 (dd,
J ϭ 16.0, 1.0 Hz, 1 H), 5.86 (d, J ϭ 10.0 Hz, 1 H), 6.60 (dt, J ϭ
H
.95 (t, J ϭ 7.1 Hz, 3 H), 1.15Ϫ1.35 (m, 14 H), 1.74 (m, 4 H), 2.10
3
(
t, J ϭ 6.5 Hz, 2 H), 2.55 (m, 1 H), 4.95 (dd, J ϭ 10.0, 1.0 Hz, 1
H), 5.05 (dd, J ϭ 16.0, 1.0 Hz, 1 H), 5.83 (d, J ϭ 10.0 Hz, 1 H),
2
13
6
.55 (td, J ϭ 16.0, 10.0 Hz, 1 H) ppm. C NMR (100.4 MHz,
CDCl ): δ ϭ 15.3, 22.5, 23.7, 25.3, 25.6, 27.2, 29.2, 31.5, 32.4, 32.8,
4.6, 36.3, 115.2, 118.4, 119.1, 150.3 ppm. MS (EI, 70 eV): m/z (rel.
3
1
2
6.0, 10.0 Hz, 1 H) ppm. 13C NMR (100.4 MHz, CDCl
2.7, 22.9, 29.8, 30.4, 30.5, 31.1, 37.0, 114.4, 125.3, 133.4, 147.5
3
): δ ϭ 14.1,
3
ϩ
int.) ϭ 220 (30) [M ], 135 (100), 93 (35), 79 (41), 67 (78). C16
220.4): calcd. C 87.19, H 12.81; found C 88.05, H 12.05.
H
28
ϩ
ppm. MS (EI, 70 eV): m/z (rel. int.) ϭ 166 (5) [M ], 109 (24), 82
52), 81 (52), 67 (100) 41 (87). C12 22 (166.3): calcd. C 86.67, H
(
(
H
13.33; found C 86.45, H 12.95.
4-Butyl-2-methylocta-1,3-diene (4h): 0.38 g (42%) as a colorless oil.
1
H NMR (200 MHz, CDCl
3
): δ ϭ 0.74Ϫ1.13 (m, 6 H), 1.13Ϫ1.76
1
,1-Dicyclopentylbuta-1,3-diene (4b): 0.82 g (86%) as a colorless oil.
(m, 8 H), 1.84 (s, 3 H), 2.03 (t, J ϭ 7.6 Hz, 2 H), 2.20 (t, J ϭ
1
13
H NMR (400 MHz, CDCl
3
): δ ϭ 1.42Ϫ1.82 (m, 16 H), 2.35 (tt,
7.6 Hz, 2 H), 4.74 (s, 1 H), 4.86 (s, 1 H), 5.64 (s, 1 H) ppm.
C
J ϭ 13.6, 7.0 Hz, 1 H), 3.01 (tt, J ϭ 13.6, 7.0 Hz, 1 H), 4.97 (dd, NMR (100.4 MHz, CDCl ): δ ϭ 14.3, 14.4, 22.8, 23.2, 24.2, 30.8,
3
J ϭ 10.0, 1.0 Hz, 1 H), 5.1 (dd, J ϭ 16.0, 1.0 Hz, 1 H), 5.95 (d, 30.9, 31.4, 37.4, 113.4, 126.9, 142.7, 142.8 ppm. MS (EI, 70 eV):
1
3
ϩ
J ϭ 10.0 Hz, 1 H), 6.72 (dt, J ϭ 16.0, 10.0 Hz, 1 H) ppm.
NMR (100.4 MHz, CDCl ): δ ϭ 25.6, 26.0, 31.7, 34.7, 42.1, 42.8,
14.4, 123.2, 133.4, 151.2. MS (EI, 70 eV): m/z (rel. int.) ϭ 190 (27)
C
13 24
m/z (rel. int.) ϭ 180 (8) [M ], 123 (37), 109 (23), 96 (99). C H
3
(180.3): calcd. C 86.59, H 13.41; found C 86.10; H 13.25.
1
ϩ
1,1-Dicyclopentyl-3-methylbuta-1,3-diene (4i): 0.56 g (55%) as a col-
[M ], 121 (77), 93 (81), 79 (100), 67 (58), 55 (22). C14
H22 (190.3):
1
orless oil. H NMR (400 MHz, CDCl
3
): δ ϭ 0.80Ϫ1.75 (m, 16 H),
calcd. C 88.35, H 11.65; found C 88.45, H 11.95.
1
.84 (s, 3 H), 2.21Ϫ2.41 (m, 1 H), 3.11Ϫ3.33 (m, 1 H), 4.71 (s, 1
1
3
-Hexyl-1,3-decadiene (4c): 0.76 g (68%) as a colorless oil. 1
3
H), 4.89 (s, 1 H), 5.73 (s, 1 H) ppm. C NMR (50.2 MHz, CDCl ):
4
H
δ ϭ 24.9, 26.3, 26.9, 32.6, 4.50, 41.9, 42.8, 113.1, 125.5, 143.4, 150.0
3
NMR (400 MHz, CDCl ): δ ϭ 0.96 (t, J ϭ 7.0 Hz, 6 H), 0.98Ϫ1.54
ϩ
ppm. MS (EI, 70 eV): m/z (rel. int.) ϭ 204 (19) [M ], 135 (100),
(
(
(
m, 16 H), 1.85 (t, J ϭ 7.5 Hz, 2 H), 2.55 (t, J ϭ 7.5 Hz, 2 H), 4.95
107 (63), 93 (76). C15
H24 (204.4): calcd. C 88.16, H 11.84; found C
dd, J ϭ 10.0, 1.0 Hz, 1 H), 5.2 (dd, J ϭ 16.0, 1.0 Hz, 1 H), 5.96
1
3
88.95, H 11.14.
d, J ϭ 10.0 Hz, 1 H), 6.86 (dt, J ϭ 16.0, 10.0 Hz, 1 H) ppm.
): δ ϭ 14.0, 23.1, 28.2, 30.4, 32.1, 32.6,
16.3, 119.1, 136.9, 150.9 ppm. MS (EI, 70 eV): m/z (rel. int.) ϭ
C
NMR (100.4 MHz, CDCl
1
2
3
1
,1-Dicyclohexyl-3-methylbuta-1,3-diene (4j): 0.52 g (45%) as a col-
1
orless oil. H NMR (200 MHz, CDCl
3
): δ ϭ 0.83Ϫ2.10 (m, 21 H),
ϩ
22 (1) [M ], 183 (100), 155 (85), 97 (35), 71 (37), 67 (19) 41 (60).
30 (222.4): calcd. C 86.40, H 13.60; found C 86.05, H 12.95.
1
.84 (s, 3 H), 2.48Ϫ2.68 (m, 1 H), 4.45 (s, 1 H), 4.67 (s, 1 H), 5.73
C
16
H
13
(s, 1 H) ppm. C NMR (50.2 MHz, CDCl
3
): δ ϭ 25.0, 27.0, 27.1,
2
8.2, 28.7, 30.9, 32.0, 36.0, 41.8, 113.2, 125.2, 130.1, 143.3 ppm.
1
,1-Dicyclohexylbuta-1,3-diene (4d): 0.84 g (77%) as a colorless oil.
ϩ
MS (EI, 70 eV): m/z (rel. int.) ϭ 232 (19) [M ], 149 (100), 107 (26),
1
H NMR (400 MHz, CDCl
J ϭ 10.6, 6.0 Hz, 1 H), 2.59 (tt, J ϭ 10.6, 6.0 Hz, 1 H), 4.98 (dd,
3
): δ ϭ 1.16Ϫ1.76 (m, 20 H), 1.94 (tt,
93 (30). C17
H28: calcd. C 87.86, H 12.14; found C 87.10, H 12.94.
1
J ϭ 10.0, 1.0 Hz, 1 H), 5.1 (dd, J ϭ 16.0, 1.0 Hz, 1 H), 5.83 (d, (3E)-6-Butyldeca-3,5-diene (4k): 0.48 g (49%) as a colorless oil. H
1
3
J ϭ 10.0 Hz, 1 H), 6.74 (dt, J ϭ 16.0, 10.0 Hz, 1 H) ppm.
NMR (100.4 MHz, CDCl ): δ ϭ 26.2, 26.4, 26.7, 27.1, 31.1, 34.4,
1.0, 41.4, 114.4, 123.1, 133.3, 154.4 ppm. MS (EI, 70 eV): m/z (rel.
C
3
NMR (200 MHz, CDCl ): δ ϭ 0.79Ϫ1.02 (m, 6 H), 1.02 (t, J ϭ
7 Hz, 3 H), 1.11Ϫ1.60 (m, 8 H), 2.04 (t, J ϭ 7.5 Hz, 4 H),
2.10Ϫ2.26 (m, 2 H), 5.62 (dt, J ϭ 16.0, 6.0 Hz, 1 H), 5.80 (d, J ϭ
3
4
ϩ
13
int.) ϭ 218 (24) [M ], 135 (100), 107 (23), 93 (41), 79 (45), 67 (68) 10.0 Hz, 1 H), 6.26 (dd, J ϭ 16.0, 10.0 Hz, 1 H) ppm. C NMR
55 (38). C16
H26 (218.4): calcd. C 88.00, H 12.00; found C 88.05,
(50.2 MHz, CDCl
3
): δ ϭ 14.6, 14.7, 23.6, 23.6, 26.6, 28.5, 31.1,
H 11.95.
31.2, 31.7, 37.6, 125.2, 126.3, 134.6, 142.2 ppm. MS (EI, 70 eV):
Eur. J. Org. Chem. 2003, 2612Ϫ2616
www.eurjoc.org
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2615

A. Deagostino, C. Prandi, C. Zavattaro, P. Venturello
FULL PAPER
m/z (rel. int.) ϭ 194 (12) [M ], 165 (10), 109 (33), 95 (99). C14
ϩ
H
26
[1]
[2]
N. Miyaura, K. Yamada, A. Suzuki, Tetrahedron Lett. 1979,
20, 3437Ϫ3440; for reviews see: N. Miyaura, A. Suzuki, Chem.
Rev. 1995, 95, 2457Ϫ2483; A. Suzuki, J. Organomet. Chem.
(194.4): calcd. C 86.52, H 13.48; found C 85.10, H 13.45.
(
3E)-1,1-Dicyclopentyl-l,3-hexadiene (4l): 0.45 g (41%) as a colorless
1
999, 576, 147Ϫ168.
1
oil. H NMR (200 MHz, CDCl
3
): δ ϭ 0.83Ϫ2.10 (m, 16 H), 0.95
W. Carruthers, Cycloaddition Reactions in Organic Synthesis,
Pergamon Press, Oxford, 1990; F. Fringuelli, A. Taticchi, Di-
enes in DielsϪAlder Reaction, John Wiley & Sons, New York,
1990; A. Kumar, Chem. Rev. 2001, 101, 1Ϫ20.
(t, J ϭ 6.5 Hz, 3 H), 1.85 (m, 1 H), 2.48Ϫ2.68 (m, 2 H), 3.01 (m,
1
6
H), 5.55 (dt, J ϭ 14.0, 6.4 Hz, 1 H), 5.80 (d, J ϭ 10.0 Hz, 1 H),
.26 (dd, J ϭ 14.0, 10.0 Hz, 1 H) ppm. 13C NMR (50.2 MHz,
[3]
R. Baker, J. W. S. Bradshaw, in Aliphatic and Related Natural
Product Chemistry, (F. D. Gunstone, Ed.), Specialist Periodical
Report, Royal Society of Chemistry, London 1983, vol. 3; K.
C. Nicolaou, J. Y. Ramphal, N. A. Petasis, C. N. Serhan, An-
gew. Chem. Int. Ed. Engl. 1991, 30, 1100Ϫ1116; V. Launay, I.
Beaude, J.-P. Quintard, Bull. Soc. Chim. Fr. 1997, 134,
937Ϫ946; B. Dominguez, B. Iglesia, A. R. de Lera, J. Org.
Chem. 1998, 63, 4135Ϫ4139; B. H. Lipshutz, B. Ullman, C.
Lindsley, S. Pecchi, D. J. Buzard, D. Dickson, J. Org. Chem.
CDCl
3
): δ ϭ 25.9, 26.7, 27.9, 29.3, 32.9, 35.4, 42.6, 47.1, 123.1,
1
26.2, 134.7, 148.6 ppm. MS (EI, 70 eV): m/z (rel. int.) ϭ 218 (19)
ϩ
[M ], 149 (100), 107 (32), 81 (100), 41 (45). C16
H26 (218.4): calcd.
C 88.00, H 12.00; found C 87.05, H 12.00.
9
-Butyl-2-methyltrideca-2,6,8-triene (4m): 0.67 g (54%) as a color-
1
less oil. H NMR (200 MHz, CDCl
.08Ϫ1.50 (m, 8 H), 1.60 (s, 3 H), 1.67 (s, 3 H), 1.96Ϫ2.26 (m, 8
H), 4.74 (s, 1 H), 4.90 (s, 1 H), 5.12 (m, 1 H), 5.58 (br. s, 1 H) ppm.
3
): δ ϭ 0.73Ϫ1.08 (m, 6 H),
1
1
998, 63, 6092Ϫ6093; Z. H. Peng, Y. L. Li, W. L. Wu, C. X.
13
3
C NMR (50.2 MHz, CDCl ): δ ϭ 14.7, 18.4, 23.2, 23.6, 26.3,
Liu, Y. L. Wu, J. Chem. Soc., Perkin Trans. 1 1996, 1057Ϫ1066.
Chem. Rev. 1984, 94, 1Ϫ278, special issue ‘‘Optical Non-
linearities in Chemistry’’.
[
[
4]
5]
2
1
1
7.7, 30.0, 30.4, 31.0, 31.3, 31.7, 37.3, 112.3, 124.9, 126.3, 132.0,
58.1, 168.1 ppm. MS (EI, 70 eV): m/z (rel. int.) ϭ 248 (13) [M ],
91 (42), 123 (67), 41 (100). C18
ϩ
H
32: calcd. C 87.02, H 12.98; found
‘‘Molecular Engineering for Advanced Materials’’, (J. Becher, K.
Schaumburg, Eds.), Kluwer Academic Publisher, 1995, 456,
C 87.58, H 12.21.
1
59.
[6]
1
,1-Dicyclohexyl-8-methylnona-1,3,7-triene (4n): 0.72 g (48%) as a
M. Schlosser, J. Organomet. Chem. 1967, 8, 9Ϫ16; M.
Schlosser, Mod. Synth. Methods 1992, 6, 227Ϫ271; A. Mordini,
Advances in Carbanion Chemistry; (V. Snieckus, Ed.), JAI Press
Inc., Greenwich CT, 1992, vol. 1, pp 1Ϫ45; M. Schlosser, F.
Faigl, L. Franzini, H. Geneste, G. Katsoulos, G. Zhong, Pure
Appl. Chem. 1994, 66, 1439; L. Lochmann, Eur. J. Inorg. Chem.
000, 1115Ϫ1126; M. Schlosser, in Organometallics in Syn-
thesis, (M. Schlosser, Ed.), John Wiley & Sons, Chichester,
002, pp. 1Ϫ352.
P. Venturello, J. Chem. Soc., Chem. Commun. 1992,
032Ϫ1033.
A. Deagostino, M. Mella, C. Prandi, P. Venturello, J. Chem.
Soc., Perkin Trans. 1 1995, 2757Ϫ2760; A. Deagostino, C.
Prandi, P. Venturello, Tetrahedron 1996, 52, 1433Ϫ1442.
C. Prandi, P. Venturello, J. Org. Chem. 1994, 59, 3494Ϫ3496
and 5458Ϫ5462.
P. Balma Tivola, A. Deagostino, C. Prandi, P. Venturello, J.
Chem. Soc., Perkin Trans. 1 2001, 437Ϫ441.
1
colorless oil. H NMR (200 MHz, CDCl
H), 1.60 (s, 3 H), 1.68 (s, 3 H), 1.70Ϫ1.85 (m, 4 H), 1.90Ϫ2.00 (m,
H), 2.70 (m, 1 H), 4.58 (br. s, 1 H), 4.91 (br. s, 1 H), 5.12 (m, 1
3
): δ ϭ 0.68Ϫ1.48 (m, 20
1
13
H), 5.55 (br. s, 1 H) ppm. C NMR (50.2 MHz, CDCl
3
): δ ϭ 18.4,
2
4
7
4.8, 26.4, 26.9, 27.0, 27.6, 27.9, 30.9, 31.9, 36.1, 38.9, 40.1, 41.8,
4.2, 112.0, 124.3, 126.0, 128.9, 129.1, 140.0, 147.5 ppm.: MS (EI,
0 eV): m/z (rel. int.) ϭ 300 (18) [M ], 217 (58), 149 (68), 41 (100).
2
ϩ
2
7]
[
C
22
H36 (300.5): calcd. C 87.93, H 12.07; found C 87.20, H 12.40.
1
(
E)-1-Methoxy-1,2-diphenylethene (6a): 0.39 g (38%) as a colorless
[8]
1
oil. H NMR (200 MHz, CDCl
6
6
3
): δ ϭ 3.82 (s, 3 H), 5.84 (s, 1 H),
.90Ϫ7.50 (m, 10 H) ppm. 13C NMR (50.2 MHz, CDCl
): δ ϭ
6.2, 89.7, 123.6, 127.3, 128.6, 128.7, 130.5, 131.4, 132.6, 132. 140.1
3
[9]
ϩ
ppm. MS (EI, 70 eV): m/z (rel. int.) ϭ210 (100) [M ], 167 (78), 165
98), 152 (68), 77 (43). C15 14O (210.3): calcd. C 85.68, H 6.71;
found C 85.58, H 7.08.
[
[
10]
11]
(
H
P. Balma Tivola, A. Deagostino, C. Prandi, P. Venturello,
Chem. Commun. 2001, 1536Ϫ1537.
P. Balma Tivola, A. Deagostino, C. Prandi, P. Venturello, Org.
Lett. 2002, 4, 1275Ϫ1277.
(
E)-1-Methoxy-1,2-diphenyl-1-propene (6b): 0.52 g (45%) as a color-
1
[12]
less oil. H NMR (200 MHz, CDCl
3
): δ ϭ 2.20 (s, 3 H), 3.47 (s, 3
H), 6.90Ϫ7.37 (m, 10 H) ppm. 1 C NMR (50.2 MHz, CDCl
3
3
): δ ϭ
8.9, 57.9, 126.6, 128.0, 128.4, 128.6, 130.0, 130.8 ppm. MS (EI,
[
[
13]
14]
A. Suzuki, J. Organomet. Chem. 2002, 653, 83Ϫ90.
G. Zweifel, R. P. Fisher, Synthesis 1972, 557Ϫ558; E. Negishi,
J.-J. Katz, R. C. Brown, Synthesis 1972, 555Ϫ556. Moreover,
to the best of our knowledge gem-dibutyl-substituted 1,3-buta-
dienes have only been prepared in an aqueous medium by reac-
tion of aldehydes and ketones with 1-chloro-3-iodopropene in
the presence of zinc powder; see: T-H. Chan, C-J. Li, Or-
ganomet., 1990, 9, 2649Ϫ2650.
Any attempt to use alkylborates instead of boranes was unsuc-
cessful; in particular we used triisopropylborate to generate the
organoboron reagent in order to prevent the formation of bor-
inic acid as observed with trimethylborate, see: W. Cabri, R.
Di Fabio, in From Bench to Market: the Evolution of Chemical
Synthesis, Oxford Press University, 2000, p. 134.
N. Miyaura, J. Organomet. Chem. 2002, 653, 54Ϫ57.
N. Miyaura, A. Suzuki, J. Organomet. Chem. 1981, 213,
C53ϪC56.
1
7
7
ϩ
0 eV): m/z (rel. int.) ϭ 224 (57) [M ], 167 (78), 181 (37), 105 (32)
7(100). C16 16O: calcd. C 85.68, H 7.19; found C 85.21; H 7.33.
H
(
E)-1-Methoxy-1-p-methoxyphenyl-2-phenyl-1-propene (6c): 0.52 g
1
(41%) as a colorless oil. H NMR (200 MHz, CDCl
3
): δ ϭ 2.17 (s,
H), 3.40 (s, 3 H), 3.73 (s, 3 H), 6.68 (d, J ϭ 9.2 Hz, 2 H),
.96Ϫ7.37 (m, 5 H), 7.55 (d, J ϭ 8 Hz, 2 H) ppm. 13C NMR
): δ ϭ 16.6, 53.6, 55.6, 111.7, 112.1, 124.2, 126.4,
27.8, 129.8, 149.7; 158.2 ppm. MS (EI, 70 eV): m/z (rel. int.) ϭ 254
3
6
[15]
(50.2 MHz, CDCl
3
1
(
ϩ
18 2
100) [M ], 211 (82), 178 (25), 165 (35) 77(23). C17H O : calcd. C
80.28, H 7.13; found C 80.33, H 7.54.
[
[
16]
17]
Acknowledgments
The authors are grateful to Dr. V. Farina (Boehringer Ingelheim
Pharmaceuticals) for his valuable suggestions. This work was sup-
ported by grants from Italian MIUR.
[18]
A. Deagostino, M. Mella, C. Prandi, P. Venturello, J. Chem.
Soc., Perkin Trans. 1 1995, 2757Ϫ2760.
K. Smith, in Organometallics in Synthesis, (M. Schlosser, Ed.),
John Wiley & Sons, Chichester, 2002, pp. 465Ϫ533.
Received March 4, 2003
[19]
2616
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2003, 2612Ϫ2616