Synthesis of (Z)-alkene-containing linear conjugated dienyl homoallylic alcohols by a palladium-catalyzed three-component reaction

Article abstract of DOI:10.1055/s-0040-1707468

A synthesis of (Z)-alkene-containing linear conjugated dienyl homoallylic alcohols by using a palladium-catalyzed three-component reaction has been developed. This method shows good functional-group compatibility and generality, with high diastereoselectivity. Additionally, in many cases, the present method controls the alkene stereochemistry of the newly formed C-C bond and overcomes the inherent preference for (E)-alkene formation, giving (Z, E)- and (Z, Z)-products.

Full text of DOI:10.1055/s-0040-1707468

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© Georg Thieme Verlag Stuttgart · New York
2020, 31, A–E
letter
A
en
Y. Horino et al.
Letter
Synlett
Synthesis of (Z)-Alkene-Containing Linear Conjugated Dienyl
Homoallylic Alcohols by a Palladium-Catalyzed Three-Component
Reaction
Yoshikazu Horino*
Juri Sakamoto
Miki Murakami
Miki Sugata
0
0
0
0-0
0
0
2-8
9
1
6-
6
2
9
8
OH
(Z/E)
(E)
Pd(OAc)2
PPh3
18 examples
32–69% yield
OAc
O
R1
*
*
Bu3Sn
+
R2
+
R2
B(pin)
R3
high diastereocontrol
Z/E ratios: 2:1 to >20:1
R1
THF
70 °C, 2–3 h
R3
Graduate School of Science and Engineering, University of
Toyama, 3190 Gofuku, Toyama 930-8555, Japan
horino@eng.u-toyama.ac.jp
Received: 19.02.2020
Accepted after revision: 13.03.2020
Published online: 14.05.2020
Various dienylmetals (Sn, Si, In, Zn, Cr, or Ti)6 and -(1,3-
dioxenylallyl)boronate7 have been successfully used for the
allylation of aldehydes to prepare dienyl homoallylic alco-
hols (Schemes 1a and 1b). However, these methods suffer
from limitations in relation to the preparation of the requi-
site organometallic reagents, regioselectivity, and function-
al-group tolerance. In addition, the reaction generally gives
a mixture of homoallylic alcohols containing linear conju-
gated (E,E)-diene (-adduct) and skipped diene (-adduct)
moieties, depending on the Lewis acid that is used.6b,8 Bisvi-
nylogous Mukaiyama aldol reactions with the correspond-
ing silyl ketene acetals furnish linear conjugated dienyl ho-
moallylic alcohols with high selectivity at the remote -po-
sition.9 Although these methods are useful for the synthesis
of linear conjugated (E,E)-dienyl homoallylic alcohols and
their derivatives, formation of the corresponding (Z)-
alkenes remains a challenge.10 To overcome this problem,
powerful catalytic methods have emerged, providing struc-
turally diverse (Z)-alkene-containing linear conjugated die-
nyl homoallylic alcohols. For example, the Hiyama−Denmark
cross-coupling reaction of 1-oxa-2-silacyclohex-3-enes
with vinyl iodides permits facile access to the desired
compounds (Scheme 1c).11 However, its application to dia-
stereoselective reactions has not yet been reported. To the
best of our knowledge, there exists only one report on a ste-
reoselective synthesis of (Z)-alkene-containing linear con-
jugated dienyl homoallylic alcohols by a Suzuki–Miyaura
cross-coupling reaction of 1,2-oxaborinan-3-enes (Scheme
1d).12 Although this is an elegant synthetic transformation,
the development of synthetic methods to access this im-
portant structural motif from easily accessible reagents still
remains a challenge.
DOI: 10.1055/s-0040-1707468; Art ID: st-2020-u0100-l
Abstract A synthesis of (Z)-alkene-containing linear conjugated dienyl
homoallylic alcohols by using a palladium-catalyzed three-component
reaction has been developed. This method shows good functional-
group compatibility and generality, with high diastereoselectivity. Addi-
tionally, in many cases, the present method controls the alkene stereo-
chemistry of the newly formed C–C bond and overcomes the inherent
preference for (E)-alkene formation, giving (Z,E)- and (Z,Z)-products.
Key words allylation, homoallylic alcohols, palladium catalysis, multi-
component reaction, vinyl stannanes
Homoallylic alcohols that incorporate a (Z)-alkene-con-
taining linear conjugated diene are widespread structural
motifs in natural products such as lactimidomycin,1
(6E,10Z)-2′-O-methylmyxalamide D,2 macrolactin A,3 and
spirangien A4 (Figure 1). In addition, they are also valuable
building blocks in organic synthesis.5
O
MeO
HN
OH
O
HO
NH
O
O
O
O
Lactimidomycin
(6E,10Z)-2'-O-Methylmyxalamide D
OH
MeO
CO2H
O
O
HO
H
O
HO
HO
H
O
MeO
OH
HO
Spirangien A
We have previously developed the stereoselective syn-
thesis of (Z)- and (E)-homoallylic alcohols by a palladium-
catalyzed three-component reaction of aldehydes, -bory-
lated allylic benzoates, and aryl stannanes (Scheme 1e).13
Macrolactin A
Figure 1 Representative structures incorporating (Z)-alkene-contain-
ing linear conjugated dienyl homoallylic alcohols
© 2020. Thieme. All rights reserved. Synlett 2020, 31, A–E
Georg Thieme Verlag KG, Rüdigerstraße 14, 70469 Stuttgart, Germany

B
Y. Horino et al.
Letter
Synlett
Table 1 Optimization of the Reaction Conditionsa
OH
(Z/E)
(E)
Pd(OAc)2
ligand
OH
OH
OAc
O
Ph
Bu3Sn
OTBS
+
+
+
+
Ph
Ph
Ph
Ph
B(pin)
Ph
1a
solvent, 70 °C
Ph
5aa
OAc
Ph
6aa
2a
3a
4aaa
OTBS
Entry
Ligand
Solvent
Time (h)
Yieldb (%) of 4aaa
Z/Ec
Yieldb (%) of 5aa Yieldb (%) of 6aa
1
2
(4-MeOC6H4)3P
(4-F3CC6H4)3P
PPh3
THF
THF
THF
THF
THF
THF
THF
2
43
30
60
39
29
40
19
44
43
44
35
40
>20:1
0
0
4
0
0
0
5
0
9
0
2
0
8
7
1.5
2
4:1
18:1
4:1
3
0
4
CyPPh2
1.5
0.5
2
24
4
5
(2-MeC6H4)3P
DPPPent
Xantphos
PPh3
4:1
6
>20:1
5:1
0
7
0.5
1.5
0.5
0.5
0.5
2
0
8
toluene
DMF
>20:1
>20:1
8:1
16
0
9
PPh3
10
11
12e
PPh3
1,4-dioxane
CPMEd
DMF
0
PPh3
>20:1
10:1
0
PPh3
0
a Reaction conditions: 1a (1.2 mmol), 2a (0.5 mmol), 3a (0.75 mmol), Pd(OAc)2 (5 mol%), ligand (10 mol% for monodentate, 5 mol% for bidentate), solvent (4
mL), 70 °C, under Ar.
b Isolated yield.
c Determined by 1H NMR analysis of the crude reaction mixture.
d CPME = cyclopentyl methyl ether.
e LiCl (1.5 mmol) was added.
We envisaged that the use of vinyl stannanes instead of aryl
stannanes might lead to a related reaction. However, this
would be particularly remarkable, given the large thermo-
dynamic preference for the (E,E)-isomer over the (Z,E)-
product.10 With the notion that our method had the poten-
tial to provide (Z)-alkene-containing linear conjugated die-
nyl homoallylic alcohols, we examined the palladium-cata-
lyzed three-component reaction of aldehydes, -borylated
allylic acetates, and vinyl stannanes.
In our initial investigation, we chose the reaction of
benzaldehyde (1a), boronate 2a, and vinylstannane 3a as a
model reaction to optimize the reaction conditions (Table
1).14 As observed in our previous work (Scheme 1e),13 the
use of (4-MeOC6H4)3P as a ligand was effective in promoting
the formation of (Z,E)-4aaa in 43% isolated yield with high
levels of alkene stereocontrol and high diastereoselectivity
(Table 1, entry 1). Among the phosphine ligands tested,
PPh3 showed the best result and afforded (Z,E)-4aaa in 60%
yield with high stereocontrol (entries 1–5). In this context,
a prolonged reaction time did not lead to isomerization of
(Z,E)-4aaa to (E,E)-4aaa. 1,5-Bis(diphenylphosphino)pen-
tane (DPPPent) and 4,5-bis(diphenylphosphino)-9,9-di-
methylxanthene (Xantphos), which showed good catalytic
activities in our previous studies,13 were ineffective (entries
6 and 7). Among the solvents tested, the use of THF gave the
best results (entries 3 and 8–11). Moreover, addition of LiCl,
which often has a positive effect in Migita–Kosugi–Stille
coupling reactions,15 had a profoundly detrimental effect,
causing a large reduction in both chemical yield and alkene
stereocontrol (entry 12). Although efforts were also made
to vary the other reaction parameters, such as the reaction
temperature, the ratio of reagents, the ratio of ligands, and
the leaving group, no further improvement in the yield of
4aaa was observed. Product 4aaa was carefully confirmed
as having an anti-configuration by its derivatization to a
known compound.16
With the optimal reaction conditions in hand, we next
assessed the reaction scope by using various aldehydes
1 with 2a and 3a (Scheme 2a).14 The reaction appeared to
be sensitive to the electronic properties of the aromatic al-
dehydes. For example, although the reaction with p-anisal-
dehyde gave 4baa in 51% yield with good alkene stereocon-
trol, the reaction with aromatic aldehydes possessing
an electron-withdrawing (trifluoromethyl, nitro, or me-
thoxycarbonyl) group in the para-position proceeded to af-
ford 4caa–eaa in 53–69% yields with high levels of alkene
stereocontrol. Nevertheless, high diastereoselectivities
were observed for all of the aromatic aldehydes exam-
ined.16 In the case of aliphatic aldehydes, the present three-
component reaction could be successfully applied to hydro-
cinnamaldehyde and isobutyraldehyde to give 4faa and
4gaa in yields of 58 and 38%, respectively, with moderate to
good alkene stereoselectivity.
© 2020. Thieme. All rights reserved. Synlett 2020, 31, A–E

C
Y. Horino et al.
Letter
Synlett
OH
*
a) Allylation of aldehydes
(Z/E)
Pd(OAc)2
PPh3
OAc
OH
R
OH
Bu3Sn
O
R1
*
O
M
+
+
R2
B(pin)
R2
+
+
R
R1
THF, 70 °C
R3
R
R3
1
2
3
(M = Sn, Si, In, Zn, Cr, Ti)
4
1a, R1 = Ph
2a, R2 = Ph
3a, R3 = CH2OTBS
b) Homologation of aldehydes
1b, R1 = 4-MeOC6H4
1c, R1 = 4-F3CC6H4
1d, R1 = 4-O2NC6H4
1e, R1 = 4-MeO2CC6H4
1f, R1 = 2-phenethyl
1g, R1 = i-Pr
2b, R2 = 4-MeOC6H4
2c, R2 = 2-MeOC6H4
2d, R2 = 3-ClC6H4
2e, R2 = 4-F3CC6H4
2f, R2 = 4-BrC6H4
2g, R2 = 2-thienyl
3b, R3 = CH2CH2OTBS
3c, R3 = n-Bu
B(pin)
OH
O
O
OH
O
3d, R3 = Ph
O
+
3e, R3 = SiMe3
3f, R3 = Si(i-Pr)3
3g, R3 = CH2OH
3h, R3 = CO2Me
R
R
O
R
O
c) Hiyama–Denmark cross-coupling reaction
OH
[(allyl)PdCl]2
(2.5 mol%)
X2
Si
a) Scope of Aldehydes (R2 = Ph, R3 = CH2OTBS)
OH OH
R1
O
R2
+
OH
X
TBAF
R1
THF, rt
R2
d) Suzuki–Miyaura cross-coupling reaction
OH
Ph
Ph
Ph
MeO
F3C
O2N
PdCl2(PPh3)2
(5 mol%)
OH
B
TBSO
TBSO
TBSO
O
I
CO2Et
+
Ph
4baa, 51%, Z/E = 10:1a
4caa, 69%, Z/E = >20:1
4daa, 53%, Z/E = >20:1
CsF (2 equiv)
CH2Cl2
Ph
CO2Et
OH
OH
OH
e) Previous work
Pd(OAc)2
(4-MeOC6H4)3P
OH
Ph
Ph
Ph
Ph
MeO2C
R1
MeCN, 70 °C
OBz
O
R2
Ar
TBSO
4eaa, 60%, Z/E = >20:1
TBSO
TBSO
ArSnBu3
+
+
R1
R2
B(pin)
4faa, 58%, Z/E = 6:1
4gaa, 38%, Z/E = 4:1
OH
Pd2(dba)3
b) Scope of Boronates (R1 = Ph, R3 = CH2OTBS)
OH OH
Ar
R1
MS 5 Å
THF, 70 °C
R2
OH
OH
f) This work
Ph
Ph
Ph
(Z)
OAc
MeO
O
+
R1
Pd cat.
R3
Bu3Sn
(E)
+
R2
B(pin)
R2
R1
OTBS
OTBS Cl
OTBS
R3
OMe
4aba, 66%, Z/E = 7:1
4aca, 48%, Z/E = 10:1
4ada, 51%, Z/E = >20:1
OH
Scheme 1 Synthesis of conjugated dienyl homoallylic alcohols
OH
OH
Ph
Ph
Ph
S
Next, we examined the generality of the reaction to-
ward various boronates 2 (Scheme 2b), and we found that
the electronic properties and the position of the substitu-
ent group on the aryl ring of 2 influenced the reactivity and
the stereocontrol of the alkene product. For example, the
presence of an electron-donating substituent, such as a me-
thoxy group, at either the ortho- or para-position of the ar-
omatic ring decreased the alkene stereocontrol in the ho-
moallylic alcohols products 4aba and 4aca, which were ob-
tained in yields of 66 and 48%, respectively. In contrast,
4ada and 4aea were obtained with high levels of alkene ste-
reocontrol when m-chloro or p-trifluoromethyl groups
were present on the aromatic ring. In addition, the 4-bro-
mo- and 2-thienyl-substituted substrates 2f and 2g, respec-
tively, were compatible with the reaction conditions, and
produced the corresponding products 4afa and 4aga in
moderate yields but with high levels of alkene stereocon-
trol. Attempts to use substrates substituted with an alkyl
group, such as a hydrocinnamyl group, resulted in complex
mixtures containing the -hydride elimination product.
Finally, the generality of the reaction toward the vinyl-
stannane was studied (Scheme 2c) and it was found that
the alkene stereochemistry of the newly formed C–C bond
depended on the substituents on vinylstannane. For exam-
ple, (E)-vinylstannanes 3b and 3c afforded the correspond-
ing products 4aab and 4aac with good to high levels of
OTBS
OTBS
OTBS
CF3
Br
4aea, 62%, Z/E = >20:1
4afa, 40%, Z/E = >20:1
4aga, 32%, Z/E = >20:1
c) Scope of Vinylstannanes (R1 = R2 = Ph)
OH
OH
OH
Ph
Ph
Ph
Ph
Ph
Ph
OTBS
n-Bu
Ph
4aab, 54%, Z/E = 18:1
4aac, 43%, Z/E = 10:1
4aad, 55%, Z/E = 3:1
OH
OH
OH
Ph
Ph
Ph
Ph
Ph
Ph
Si
CO2Me
OH
4aae, Si = SiMe3, 50%, Z/E = 2:1
4aaf, Si = Si(i-Pr)3, 0%
4aag, 0%
4aah, 0%
Scheme 2 Scope of the palladium-catalyzed three-component reac-
tion. Reagents and conditions: 1 (1.2 mmol), 2 (0.5 mmol), 3 (0.75
mmol), Pd(OAc)2 (5 mol%), PPh3 (10 mol%), THF (4 mL), 70 °C, 2–3 h.
aThe Z/E ratios were determined by 1H NMR analysis of the crude reac-
tion mixture.
alkene stereocontrol. In contrast, moderate levels of alkene
stereocontrol were observed in the formation of 4aad and
4aae when -(tributylstannyl)styrene (3d) and trimeth-
yl[2-(tributylstannyl)vinyl]silane (3e), respectively, were
used. Unfortunately, an attempt to use (E)-vinylstannanes
© 2020. Thieme. All rights reserved. Synlett 2020, 31, A–E

D
Y. Horino et al.
Letter
Synlett
bearing a triisopropylsilyl group in a vicinal position, for
example, (E)-triisopropyl[2-(tributylstannyl)vinyl]silane
reoselectivity. Additionally, in many cases, the present
method provides control of the alkene stereochemistry of
the newly formed C–C bond and overcomes the inherent
preference for (E)-alkene formation, giving (Z,E)- and (Z,Z)-
products.
(3f), failed in this three-component reaction, presumably as
a result of steric hindrance caused by the triisopropylsilyl
group. In addition, (E)-3-(tributylstannyl)prop-2-en-1-ol
(3g) and methyl (E)-3-(tributylstannyl)prop-2-enoate (3h)
did not engage in the present reaction; instead, a trace
amount of the palladium-catalyzed coupling product of bo-
ronate 2a with the vinylstannane 3 was observed.17
In an attempt to expand the scope of the vinylstannane,
the reaction was performed with the sterically encumbered
vinylstannane (Z)-3a (Scheme 3). However, a decreased
alkene stereoselectivity was observed for the newly formed
bond (Z/E = 8:1), and (Z,Z)-4aaa was obtained in 38% yield.
In this context, unreacted (Z)-3a was recovered without any
isomerization after the reaction.
Funding Information
This work was financially supported by JSPS KAKENHI Grant Number
JP15K05496.
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Supporting Information
Supporting information for this article is available online at
https://doi.org/10.1055/s-0040-1707468.
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References and Notes
OH
Pd(OAc)2 (5 mol%)
PPh3 (10 mol%)
(Z/E)
Bu3Sn
OTBS
1a
+ 2a +
Ph
OTBS
(1) (a) Larsen, B. J.; Sun, Z.; Nagorny, P. Org. Lett. 2013, 15, 2998.
(b) Nagasawa, T.; Kuwahara, S. Org. Lett. 2013, 15, 3002.
(2) Wang, G.; Huang, Z.; Negishi, E. Org. Lett. 2008, 10, 3223.
(3) (a) Smith, A. B.; Ott, G. R. J. Am. Chem. Soc. 1996, 118, 13095.
(b) Smith, A. B.; Ott, G. R. J. Am. Chem. Soc. 1998, 120, 3935.
(c) Kim, Y.; Singer, R. A.; Carreira, E. M. Angew. Chem. Int. Ed.
1998, 37, 1261. (d) Fukuda, A.; Kobayashi, Y.; Kimachi, T.;
Takemoto, Y. Tetrahedron 2003, 59, 9305. (e) Yadav, J. S.; Kumar,
M. R.; Sabitha, G. Tetrahedron Lett. 2008, 49, 463.
(4) Gregg, C.; Gunawan, C.; Ng, A. W. Y.; Wimala, S.;
Wickremasinghe, S.; Rizzacasa, M. A. Org. Lett. 2013, 15, 516.
(5) Do, H.; Kang, C. W.; Cho, J. H.; Gilbertson, S. R. Org. Lett. 2015,
17, 3972.
(6) For reactions involving Sn, see: (a) Yanagisawa, A.; Nakashima,
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(b) Nishigaichi, Y.; Hanano, Y.; Takuwa, A. Chem. Lett. 1998, 27,
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M.; Takuwa, A. J. Chem. Soc., Perkin Trans. 1 1992, 2581. Si:
(f) Seyferth, D.; Pornet, J. J. Org. Chem. 1980, 45, 1721.
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1982, 1, 1651. (h) Hosomi, A.; Saito, M.; Sakurai, H. Tetrahedron
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M.; Araki, S. J. Organomet. Chem. 1997, 549, 305. In: (k) Woo, S.;
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THF, 70 °C
Ph
(Z)-3a
(Z,Z)-4aaa, 38%, Z/E = 8:1
Scheme 3 Palladium-catalyzed three-component reaction of a (Z)-vi-
nylstannane
The scalability of this three-component reaction was
demonstrated by an experiment scaled up to a gram scale
of 2a, in which 4aaa was produced in 50% yield (Scheme 4).
OH
Pd(OAc)2 (5 mol%)
PPh3 (10 mol%)
(Z/E)
(E)
Ph
+
+
1a
2a
(5 mmol)
3a
Ph
THF
70 °C, 3 h
(2.4 equiv)
(1.5 equiv)
4aaa, 50%
Z/E = >20:1
OTBS
Scheme 4 A gram-scale reaction
Furthermore, to evaluate the usefulness of the hydroxy
and conjugated dienyl groups, a manipulation of the ho-
moallylic alcohol 4aaa obtained in this study was per-
formed (Scheme 5). A vanadium-catalyzed hydroxy-direct-
ed epoxidation reaction18 [VO(acac)2 (2 mol%), t-BuOOH] af-
forded epoxide syn-7 in 55% isolated yield (dr > 20:1).
OH
OH
O
VO(acac)2 (2 mol%)
t-BuOOH (2 equiv)
Ph
Ph
Ph
Ph
CH2Cl2
rt, 15 h
OTBS
OTBS
4aaa
7, 55%
Scheme 5 Hydroxy-directed epoxidation
(7) Hoffmann, R. W.; Schäfer, F.; Haeberlin, E.; Rohde, T.; Körber, K.
Synthesis 2000, 2060.
(8) (a) Koreeda, M.; Tanaka, Y. Chem. Lett. 1982, 11, 1299. (b) Marx,
A.; Yamamoto, H. Angew. Chem. Int. Ed. 2000, 39, 178.
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Sartori, A.; Lodola, A.; Mor, M.; Rassu, G.; Pelosi, G.; Zanardi, F.;
Casiraghi, G. Org. Lett. 2011, 13, 4738. (c) Curti, C.; Sartori, A.;
In conclusion, we have developed a diastereoselective
synthesis of (Z)-alkene-containing linear conjugated dienyl
homoallylic alcohols by using a palladium-catalyzed three-
component reaction of aldehydes, -borylated allylic ace-
tates, and vinylstannanes. This method shows good func-
tional-group compatibility and generality, with high diaste-
© 2020. Thieme. All rights reserved. Synlett 2020, 31, A–E

E
Y. Horino et al.
Letter
Synlett
Battistini, L.; Brindani, N.; Rassu, G.; Pelosi, G.; Lodola, A.; Mor,
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Commun. 2012, 48, 8661. (c) Lu, G.-P.; Voigtritter, K. R.; Cai, C.;
Lipshutz, B. H. J. Org. Chem. 2012, 77, 3700.
(11) (a) Denmark, S. E.; Yang, S.-M. Tetrahedron 2004, 60, 9695.
(b) Denmark, S. E.; Yang, S.-M. Org. Lett. 2001, 3, 1749.
(c) Elbert, B. L.; Lim, D. S. W.; Gudmundsson, H. G.; O’Hanlon, J.
A.; Anderson, E. A. S. Chem. Eur. J. 2014, 20, 8594.
mL) was then added, and the mixture was then stirred at 70 °C
for 2 h until the reaction was complete. The resulting mixture
was diluted with EtOAc (10 mL) and washed with sat. aq NH4Cl
(2 × 10 mL), sat. aq NaHCO3 (2 × 10 mL), and brine (2 × 10 mL).
The combined organic layers were dried (MgSO4) and concen-
trated, and the residue was purified by chromatography [silica
gel, EtOAc–hexane (1:4)] to give a yellow oil; yield: 118.4 mg
(60%); Rf = 0.41 (EtOAc–hexane, 1:4).
1H NMR (400 MHz, CDCl3):  = 7.23–7.12 (m, 8 H), 7.07 (dm, J =
7.6 Hz, 2 H), 6.58 (dd, J = 11.2, 14.8 Hz, 1 H), 6.27 (t, J = 11.2 Hz,
1 H), 5.87 (t, J = 10.4 Hz, 1 H), 5.79 (td, J = 4.4, 14.8 Hz, 1 H), 4.84
(d, J = 7.6 Hz, 1 H), 4.22 (d, J = 4.4 Hz, 2 H), 4.04 (dd, J = 7.6, 10.4
(12) Miura, T.; Nakahashi, J.; Zhou, W.; Shiratori, Y.; Stewart, S. G.;
Murakami, M. J. Am. Chem. Soc. 2017, 139, 10903.
Hz, 1 H), 2.22 (s, 1 H), 0.94 (s, 9 H), 0.08 (s, 3 H), 0.06 (s, 3 H). 13
C
(13) (a) Horino, Y.; Sugata, M.; Mutsuura, I.; Tomohara, K.; Abe, H.
Org. Lett. 2017, 19, 5968. (b) Horino, Y.; Sugata, M.; Abe, H. Adv.
Synth. Catal. 2016, 358, 1023.
NMR (125 MHz, CDCl3):  = 142.0, 141.2, 134.9, 131.4, 129.5,
128.5, 128.4, 128.0, 127.5, 126.72, 126.66, 124.4, 78.1, 63.4,
53.0, 26.1, 18.5, –5.1. HRMS (EI): m/z [M – OH]+ calcd for
(14) anti-(3Z,5E)-7-{[tert-butyl(dimethyl)silyl]oxy}-1,2-diphenyl-
hepta-3,5-dien-1-ol (4aaa); Typical Procedure
C25H33OSi: 377.2295; found: 377.2260.
(15) Scott, W. J.; Stille, J. K. J. Am. Chem. Soc. 1986, 108, 3033.
(16) See the Supporting Information for details.
(17) Del Valle, L.; Stille, J. K.; Hegedus, L. S. J. Org. Chem. 1990, 55,
3019.
A 10 mL, two-neck, round-bottomed flask was charged with
Pd(OAc)2 (11.2 mg, 0.1 mmol), Ph3P (26.4 mg, 0.2 mmol), and
THF (1 mL), and the mixture was stirred at 70 °C for 0.5 h. A
solution of 1a (151.1 mg, 0.5 mmol), PhCHO (2a; 123 L, 1.2
mmol), and vinylstannane 3a (346.1 mg, 0.75 mmol) in THF (3
(18) Hoveyda, A. H.; Evans, D. A.; Fu, G. C. Chem. Rev. 1993, 93, 1307.
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