Palladium-catalyzed reaction of γ-silylated allyl acetates proceeding through 1,2-shift of a substituent on silicon

Article abstract of DOI:10.1016/j.tet.2020.131493

The palladium-catalyzed reaction of γ-silylated allyl acetates with water in the presence of CsF induces a previously unprecedented 1,2-shift of a substituent on silicon to produce allylsilanes in situ. The catalytic activity of the palladium increased when using an electron-poor phosphine ligand possessing fluorinated substituents. Further investigation of the reaction revealed that the approximate order of the migratory aptitude of groups from silicon was PhC≡C, allyl > Bn > Ph, vinyl > alkyl (Me, Et). A density functional theory study was employed to explore the reaction mechanism. Finally, the Hosomi–Sakurai-type allylation of aldehydes with in situ-generated α,γ-disubstituted allylsilanes was also investigated.

Full text of DOI:10.1016/j.tet.2020.131493

Tetrahedron 76 (2020) 131493
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Palladium-catalyzed reaction of
g
-silylated allyl acetates proceeding
through 1,2-shift of a substituent on silicon
,
, **
Yoshikazu Horino a *, Mayo Ishibashi a, Kosuke Nakasai a, Toshinobu Korenaga b
a Department of Environmental Applied Chemistry, Faculty of Engineering, University of Toyama, Toyama, 930-8555, Japan
b Department of Chemistry and Bioengineering, Faculty of Engineering, Iwate University, Morioka, Iwate, 020-8551, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
The palladium-catalyzed reaction of g-silylated allyl acetates with water in the presence of CsF induces a
Received 4 April 2020
Received in revised form
7 August 2020
Accepted 8 August 2020
Available online 16 August 2020
previously unprecedented 1,2-shift of a substituent on silicon to produce allylsilanes in situ. The catalytic
activity of the palladium increased when using an electron-poor phosphine ligand possessing fluorinated
substituents. Further investigation of the reaction revealed that the approximate order of the migratory
aptitude of groups from silicon was PhC≡C, allyl > Bn > Ph, vinyl > alkyl (Me, Et). A density functional
theory study was employed to explore the reaction mechanism. Finally, the HosomieSakurai-type
allylation of aldehydes with in situ-generated
a
,g
-disubstituted allylsilanes was also investigated.
Keywords:
© 2020 Elsevier Ltd. All rights reserved.
p-Allylpalladium
Migration
Palladium
Allylsilanes
Homoallylic alcohols
1. Introduction
bond forming reactions with organosilanes, although the p-allyl-
palladium-mediated reaction has been widely studied in a large
number of important organic transformations [16,17]. In this
context, DeShong et al. developed the palladium-catalyzed phe-
nylation of allylic benzoates using tetrabutylammonium triphe-
Due to their increased Lewis acidity at silicon atom and
enhanced SieC bond reactivity, hypervalent organosilicate species
constitute important key intermediates in organic synthesis and
exhibit rich and diverse chemistry in carbonecarbon bond forming
reactions [1e4]. For example, transition-metal-catalyzed cross-
coupling reactions such as the Hiyama coupling reaction have
emerged as particularly valuable synthetic tools because of the
many attractive properties of organosilanes, such as ease of prep-
aration, stability, and environmentally benign nature [5e7]. In
another well-studied exampledthe HosomieSakurai reac-
tiondthe allylation of carbonyl groups with allylsilanes proceeds
stereoselectively with high functional group tolerance, compared
with other organometallic reagents of the main-group elements
[8e14]. Recently, the defluoroallylation of trifluoromethylarenes
with allylsilanes was reported by the Bandar group, wherein a
fluoride-anion-induced single-electron-transfer pathway was
responsible for the CeF substitution event [15]. In contrast, there
nyldifluorosilicate (TBAT) as
a hypervalent silicate [18e23].
Although TBAT is still a useful reagentdnot only as a potent source
of the fluoride anion [20,24,25] but also in palladium-catalyzed
coupling reactions [23]dthe lack of reports on the functional
group-tolerant synthesis of TBAT derivatives [22] indicates that
there is further need for alternative strategies in its application to
carbonecarbon bond forming reactions.
We previously found that silyl-substituted
termediate A, generated from the palladium-catalyzed reaction of
-silylated allylic acetates in the presence of CsF, exhibited unique
p-allylpalladium in-
g
reactivities other than simple allylation [26,27]. For example, we
reported the stereoselective cyclopropanation of strained alkenes
by the palladium-catalyzed reaction of
g-silylated allyl acetates,
which was proposed to proceed via the formation of putative pal-
ladacyclobutene C from B (Scheme 1a) [26]. Furthermore, in the
presence of the 2,20-bipyridine ligand, palladium-stabilized vinyl-
are few reports on
p-allylpalladium-mediated carbonecarbon
carbene intermediate D was formed from
carbene dimerization (Scheme 1b) [27]. These examples indicate
that an in situ-generated a cationic silylated -allylpalladium in-
termediates A and A’ (or a transient gem-silyl- -allylpalladium
В’, which underwent
* Corresponding author.
** Corresponding author.
E-mail addresses: horino@eng.u-toyama.ac.jp (Y. Horino), korenaga@iwate-u.ac.
jp (T. Korenaga).
p
s
https://doi.org/10.1016/j.tet.2020.131493
0040-4020/© 2020 Elsevier Ltd. All rights reserved.

2
Y. Horino et al. / Tetrahedron 76 (2020) 131493
routes to acylsilanes as precursors for
[29,30], and high reaction temperatures are required for such
rearrangements (>210 ꢀC), the thermal rearrangement of
-ace-
toxysilanes has not yet evolved as a practical and general synthetic
method. Herein, we report the palladium-catalyzed reaction of
silylated allyl acetates with water, in which a previously unprece-
dented 1,2-shift of a substituent on silicon in the silylated -allyl-
a-acetoxysilanes are limited
a
g
-
p
palladium intermediate is induced (Scheme 2a) [31e35]. Then, the
HosomieSakurai-type allylation of aldehydes with in situ-
generated a,g-disubstituted allylsilanes E was also examined.
2. Results
2.1. Optimization
Initially, we screened the palladium-catalyzed reaction of
g-
trimethylsilyl-substituted allyl acetate 1 with water by evaluating
various ligands (Table 1). The reaction of 1 (1 equiv) and H2O (1.2
equiv) in the presence of Pd(OAc)2 (5 mol%), PPh3 (20 mol%), and
CsF (3 equiv) in 1,4-dioxane under an argon atmosphere at 100 ꢀC
formed only an unexpected by-product, (E)-2c (entry 1). The re-
action pathway leading to (E)-2c is not presently clear. In the
presence of an electron-rich phosphine ligand such as a P(4-
MeOC6H4)3, no conversion was observed, even though electron-
rich phosphines are known to promote the palladium-catalyzed
phenylation of allyl benzoates using TBAT (entry 2) [21]. These
results suggest that the ligands decrease the electrophilicity of
Scheme 1. Reactivities of silylated
p-allylpalladium intermediates.
cationic p-allylpalladium intermediate A”, as shown in Scheme 2a.
intermediate) play important roles in determining the reaction
path. We envisioned that this concept could be extended to the
generation of allylsilane E (Scheme 2a), wherein the intramolecular
migration of a substituent on silicon to an allylic carbon in hyper-
valent organosilicate intermediate A” would be induced. In fact,
The efficiency of this transformation appears to be highly depen-
dent on the electronic properties of the phosphine ligand. To our
delight, the catalytic activity of palladium significantly improved
when the ligand was changed to electron-poor phosphines pos-
sessing fluorinated substituents (entries 3e8). For example, the use
of P(4-FC6H4)3 produced 2a and (E)-2b in 46% and 10% yields,
respectively (entry 3). Further sequential improvements were
observed upon switching to P(4,5-F2C6H3)3 (total 75%, entry 5),
P(3,4,5-F3C6H2)3 (total 76%, entry 6), P(4-CF3C6H4)3 (total 76%, entry
7), and P(3-F-4-CF3C6H3)3 (total 71%, entry 8). Thus, electron-poor
phosphine ligands possessing fluorinated substituents play a
crucial role in the process of 1,2-shift. The reason that palladium
complexes ligated by electron-poor phosphines favor 1,2-shift is
that makes the palladium center more electrophilic. Accordingly,
Buynak et al. reported the thermal rearrangement of
a-acetox-
ysilanes to silyl acetates, where intramolecular coordination be-
tween the silicon and carbonyl oxygen atoms was critical to
promote the reaction (Scheme 2b) [28]. However, as synthetic
the resulting
p-allylpalladium intermediate is susceptible to
intramolecular nucleophilic attack from the substituent on silicon.
It should be noted that phosphines with increased electron defi-
ciency, such as P(3,5-F2-4-CF3C6H2)3, P[3,5-(CF3)2C6H3]3, P(C6F5)3,
or P(BFPy)3 [36,37] were not effective for this transformation (en-
tries 9e12). The yield of the products was lower when the phos-
phine/palladium (P:Pd) ratio was 3:1 rather than 4:1 (entry 13).
Based on these experiments, both P(3,4,5-F3C6H2)3 and P(4-
CF3C6H4)3 were promising ligands. However, when P(3,4,5-
F3C6H2)3 was applied in cases with heteroaryl-substituted silyl
groups instead of a trimethylsilyl group, the transformation was not
general, and broader evaluation identified P(4-CF3C6H4)3 as
optimal. In addition, the catalyst loading could be reduced to
2.5 mol% without significant loss of catalytic activity when using
P(4-CF3C6H4)3 (entry 14). Although the combination of CsF and 18-
crown-6 is known to be effective for the generation of hypervalent
silicates [15,25,38], the addition of 18-crown-6 failed to promote
the present reaction (entry 15). Nevertheless, the reaction requires
activation by the fluoride anion, as was shown by the absence of
desired products when the reaction was performed without a
fluoride anion source (entries 16 and 17). It is worth noting that use
of TBAT instead of CsF promoted protodesilylation of 1 to give 1-(3-
acetoxy-1-propen-1-yl)naphthalene in 55% yield (entry 18). In
Scheme 2. 1,2-Shift of a substituent on silicon to carbon.

Y. Horino et al. / Tetrahedron 76 (2020) 131493
3
Table 1
Optimization of reaction conditions.a
entry
ligand
time (h)
2a (%)
E/Z
(E)-2b (%)
(E)-2c (%)
1
2
3
4
5
6
7
8
PPh3
P(4-MeOC6H4)3
P(4-FC6H4)3
12
12
4.5
9
4
5
0
0
46
43
58
60
62
57
0
0
7
1:6.6
1:7
1:7
1:7.2
1:7.2
1:7.1
1:8.6
10
10
17
16
14
14
3
P(3,5-F2C6H3)3
P(4,5-F2C6H3)3
P(3,4,5-F3C6H2)3
P(4-CF3C6H4)3
P(3-F-4-CF3C6H3)3
P(3,5-F2-4-CF3C6H2)3
P[3,5-(CF3)2C6H3]3
P(C6F5)3
5
6
6
2
5
9
11
24
12
12
22
10
12
12
12
1
15
10
11
12b
13c
14d
15e
16f
17g
18h
19i
20j
complex mixture
0
0
46
55
0
0
0
0
0
11
17
0
0
0
0
0
P(BFPy)3
P(4-CF3C6H4)3
P(4-CF3C6H4)3
P(4-CF3C6H4)3
P(4-CF3C6H4)3
P(4-CF3C6H4)3
P(4-CF3C6H4)3
e
1:7.5
1:7.2
5
0
0
52
12
4.5
P(4-CF3C6H4)3
1:7.7
15
a
Conditions: 1 (0.5 mmol), H2O (0.6 mmol), Pd(OAc)2 (5 mol%), ligand (20 mol%), CsF (1.5 mmol) in 1,4-dioxane (3 mL) at 100 ꢀC.
P(BFPy)3 ¼ tris{2,6-bis(trifluoromethyl)-4-pyridyl}phosphine.
P(4-CF3C6H4)3 (7.5 mol%) was used.
Pd(OAc)2 (2.5 mol%) and ligand (10 mol%) were used.
18-crown-6 (0.9 mmol) was used.
CsOAc was used instead of CsF.
Reaction was performed in the absence of CsF.
ΤВАΤ was used instead of CsF.
Reaction was performed in the absence of Pd(OAc)2 and ligand, and 1 was recovered in 98%.
b
c
d
e
f
g
h
i
j
Reaction was performed in the absence of H2O.
addition, palladium-catalyzed phenylation of 1 with TBAT was not
observed [18,20e23]. The reaction also failed in the absence of the
Pd catalyst and 1 was recovered in 98% yield, proving that the
trace amounts of water contained in the solvent and CsF (entry 20).
Although many efforts have been made to detect the allylsilane
derivatives that would be expected in the absence of water, hy-
drolysis could not be avoided, probably because the hypervalent
allylsilanes generated in our system are not sufficiently stable.
formation of a
p-allylpalladium intermediate plays an important
role in the present process (entry 19). Finally, the reaction was
examined in the absence of water, which is expected to intercept
the in situ-generated allylsilane intermediates. 1H NMR monitoring
experiments before quenching the reaction mixture did not reveal
the presence of allylsilane intermediates. Instead, 2a and (E)-2b
were obtained in 52% and 15% yields, respectively, likely due to the
Table 2
Substrate scope.a.
entry
substrate (R)
time (h)
a (%)
E/Z
b (%)
1
2
3
4
6 (R ¼ Ph)
6
3
7a: 76
9a: 28
17.5:1
20:1
3.2:1
1:1
1.2:1
1:3.3
8 (R ¼ 4-CF3C6H4)
10 (R ¼ 4-MeOC6H4)
12 (R ¼ 2-furyl)
14 (R ¼ 2-thienyl)
16 (R ¼ Et)
9b: 58
11
7
11
12
24
11a: 51
13a: 25
15a: 13
17a: 33
19a: 0
11b: 33
13b: 39
15b: 49
17b: 15
19b: 0
5
6
7b
18 (R ¼ i-Pr)
a
Conditions: substrate (0.5 mmol), H2O (0.6 mmol), Pd(OAc)2 (2.5 mol%), P(4-
CF3C6H4)3 (10 mol%), CsF (1.5 mmol) in 1,4-dioxane (3 mL) at 100 ꢀC.
b
18 was recovered in 78% isolated yield.
Scheme 3. Effect of leaving group on the efficiency of the 1,2-shift of methyl group
from silicon to carbon.

4
Y. Horino et al. / Tetrahedron 76 (2020) 131493
Interestingly, it was found that the identity of the leaving group also
has an influence on the 1,2-shift of a methyl group from silicon to
carbon (Scheme 3). The reaction of 3 bearing a pivaloyloxy group
instead of an acetoxy group exhibited similar reactivity in the
model reaction compared with 1 (Table 1, entry 14), affording
desired products 2a and (E)-2b in 52% and 20% yields, respectively.
In contrast, limited conversion was observed when substrates 4 and
5, equipped with benzoyloxy and ethoxycarbonyloxy groups, were
employed.
the reaction time was prolonged. Substrates 12 and 14, bearing
heteroaryl substituents (2-furyl and 2-thienyl), were also
employed, with both providing high yields (entries 4 and 5). The
reaction proceeded with triethylsilyl-substituted substrate 16 (en-
try 6); the moderate yield of 17 was likely due to its volatility.
Interestingly, no
benzene or 1-phenyl-1-propene were observed, which might rule
out pathways involving -ethylpalladium(II) intermediates. An
b-hydrogen elimination products such as allyl-
s
attempt to use triisopropylsilyl-substituted substrate 18 resulted in
no reaction, and 18 was recovered in 78% yield (entry 7).
2.2. Scope
2.3. Study on relative migratory aptitudes
Having determined the optimal conditions, we subsequently
explored the reaction scope using various
g
-silyl-substituted allyl
Next, we evaluated the relative migration aptitude of 1,2-shift of
a substituent on silicon. In cases with both methyl and aryl groups,
such as g-dimethylphenylsilyl-substituted allyl acetate 20, migra-
acetates (Table 2). The reaction with -triphenylsilyl-substituted
g
substrate 6 proceeded at 100 ꢀC to provide the corresponding
product 7a in 76% yield (entry 1). Moreover, the reaction tolerated
both electron-deficient and electron-rich aryl groups such as those
in 8 and 10. Thus, the reaction of 8 gave migration products 9 in 86%
yield (entry 2). When substrate 10 possessing an electron-donating
group on the aromatic ring was subjected to the reaction, a longer
time was required to achieve full conversion to 11. This indicates
that the formation of silicate intermediates is facilitated when
electron-withdrawing substituents are attached to silicon. In
addition, no alkene isomerization in products 11a was observed if
tion from silicon took place with a moderate but not exclusive
preference for the phenyl group over the methyl group (Scheme
4a). To obtain further insight into the migration tendency, a 1:1
mixture of 1 and 22 was subjected to the optimal reaction condi-
tions (Scheme 4b). After quenching at an early stage of the reaction
(100 ꢀC, 2 h), products 2 and 21 were isolated in 16% and 22% yields,
respectively. No crossover products were observed. In addition, this
crossover experiment provides additional information about the
kinetics of the reaction, clearly revealing that the phenyl group
migrated about 1.4 times faster than the methyl group. Even when
the crossover experiment was carried out until completion of the
reaction, no crossover products were observed (Scheme 4c). As in
the case of 16 (Table 2, entry 6), no b-hydride elimination products
from 23, such as 1-(2-propenyl)naphthalene or 1-(1-propenyl)
naphthalene, were observed. If the protodesilylation of 1 occurs at
the early stage of the reaction, the resulting
p-allylpalladium in-
termediate and silicate species would undergo the intermolecular
coupling reaction. To assess such possibility, the palladium-
catalyzed reaction of 1 with water was examined in the presence
of 1-(3-methoxyphenyl)-2-propenyl acetate (Scheme 4d) [39]. As a
Scheme 4. Relative migratory aptitudes and crossover experiments.
Scheme 5. Approximate orders of migratory aptitude.

Y. Horino et al. / Tetrahedron 76 (2020) 131493
5
result, 2a and 2b were obtained in 61% and 13% yields, respectively
and 3-(3-methoxyphenyl)-2-propenyl acetate was recovered in
75%. These results indicate that the migration of a substituent on
silicon proceeds in an intramolecular manner.
migratory aptitude than a methyl group, although slightly modified
reaction conditions were required to give products in good yields.
Nevertheless, the present reaction system provides synthetically
useful 1,3-enyne 33a and skipped enyne 33b in 11% and 57% yield,
respectively. Based on these experiments, the approximate order of
migratory aptitude was found to be PhC≡C, allyl > Bn > Ph,
vinyl > alkyl (Me, Et); this trend is similar to that observed for the
Subsequently, we explored the approximate relative order of
migratory aptitude. Steric hindrance around the silicon atom has a
significant influence on the reaction outcome. For example, as in
the case of substrate 18, tert-butyldimethylsilyl-substituted sub-
strate 25 underwent no reaction (Scheme 5a). Changing the tert-
butyl group of 25 to a vinyl group afforded methyl migration
products 2 and vinyl migration products 27 as a mixture of con-
jugated diene 27a and skipped diene 27b. This result indicated that
the vinyl group has a migratory aptitude similar to that of a phenyl
group (Scheme 5b). The yields of 2 and 27 were determined after
hydrogenation. More selective migration was observed in
benzyldimethylsilyl-substituted substrate 28. Interestingly, the re-
previously reported thermal rearrangements of
[28].
a-acetoxysilanes
2.4. DFT calculations of the reaction mechanism
Finally, the detailed mechanism of the 1,2-shift reaction was
considered (Scheme 6). In the reaction of substrate 34, oxidative
addition of PdL2 (L ¼ P(4-CF3C6H4)3) occurs in the first step to give
p-allyl PdL2 complex 35, similarly to the Tsuji-Trost reaction. Since
action of g-allyldimethylsilyl-substituted allyl acetate 30 showed
the reaction proceeds in an intramolecular manner, as experi-
mentally confirmed above, the subsequent migration of the methyl
group should proceed through a transition state in which SieC
bond breaking and CeC bond forming occur simultaneously. The
an exclusive preference for allyl group migration over that of a
methyl group to give 31a and 31b, respectively (Scheme 5c).
Similarly, we found that a phenylethynyl group had a greater
Scheme 6. Plausible migration models in the presence or absence of fluoride anion.

6
Y. Horino et al. / Tetrahedron 76 (2020) 131493
acceleration effect of the fluoride anion (Table 1, entries 16 and 17)
obviously involves activation of the silicon atom in the transition
state of migration, considering past reports (see Scheme 1) [26,27].
Therefore, plausible migration models in the presence or absence of
fluoride anions were proposed as follows: a) activation with acetate
anion (36-TS36-37-37), b) activation with acetate and fluoride anions
(38-TS38-39-39), c) activation with fluoride anion in the presence of
L2 (40-TS40-41-41), and d) activation with fluoride anion in the
presence of L (42-TS42-43-43). The proposed mechanisms were
evaluated on the basis of density functional theory (DFT)
calculations.
All structures, including transition states, were fully optimized
and characterized using frequency calculations at the B3LYP-D3
level with the 6-31þG(d,p) basis set for the organic molecules
and the LanL2DZ basis set (with effective core potentials) for
palladium and cesium atoms using Gaussian 16, revision C.01 [40].
The structures of the transition states were checked by intrinsic
reaction coordinate (IRC) calculations [41]. The Gibbs free energies
were initially computed for the gas phase. The relative Gibbs free
energies in 1,4-dioxane were obtained using single-point energy
calculations of the optimized structures at the B3LYP-D3 functional
with the 6-31þG(2d,p) basis set for the organic molecules and the
LanL2DZ basis set with the SCRF method based on CPCM followed
by the addition of thermal corrections, which were calculated using
the above-mentioned geometrical optimizations. The calculation
results are shown in Fig. 1.
differences in energy between 42 and the individual transition
states (TS36-37, TS38-39, TS40-41, TS42-43). The smallest Gs (22.8 kcal/
mol) for the migration step occurs in pathway d), that is, activation
D
with the fluoride anion in the presence of L, and is a reasonable
energy value for the reaction to proceed. In contrast, the
D
Gs
(34.3 kcal/mol) for the migration activated with the acetate anion,
pathway a), is too large for the reaction to progress. These results
are identical to the experimental findings (Table 1, entry 7 vs. 16 or
17). In a similar manner, pathways b) and c) are not practical
because of their high
D
Gs values (
D
Gs ¼ 69.6 and 35.7 kcal/mol,
respectively). These theoretical considerations suggest that the
migration step proceeds via pathway d). The activation energy of
the migration step is higher than that of the oxidative addition
(22.8 kcal/mol vs. 21.0 kcal/mol), indicating that the rate-
determining step is migration.
2.5. Allylation of aldehydes with in situ-generated
allylsilanes
a,g-disubstituted
As the in situ formation of
a,g-disubstituted allylsilanes was
supported based on the above experimental results and theoretical
The ligand exchange of
should occur easily, and the most stable complex is
complex 42 (relative free energy,
p
-allyl Pd complexes (35, 36, 38, 40, 42)
-allyl Pd(L)F
G ¼ ꢁ27.0 kcal/mol), indicating
p
D
that it is in a resting state. In other words, all equilibrium in-
termediates (36, 38, 40) drop in at resting state 42 before pro-
ceeding to the respective transition state for each pathway. The
subsequent migration of the methyl group starts from complex 42
and proceeds through each transition state after ligand exchange.
Therefore, the activation energies (D
Gs) were calculated by the
Scheme 7. Allylation of benzaldehyde with 34 and 16.
Fig. 1. Computed reaction profiles (CPCM(1,4-dioxane)/B3LYP-D3/6-31þG(2d,p)/LanL2DZ//B3LYP-D3/6-31þG(d,p)/LanL2DZ).

Y. Horino et al. / Tetrahedron 76 (2020) 131493
7
Scheme 8. Allylation of benzaldehyde with 48.
Scheme 10. Gram-scale reaction.
studies, we next assessed their applicability in the Hoso-
mieSakurai-type allylation of aldehydes. Using the optimized re-
action conditions, the reaction of 34 with benzaldehyde afforded
adduct (E)-44 in 48% yield as a mixture of diastereomers (syn/
anti ¼ 1.4:1), along with -adduct 45 in 14% yield as a 1:4.6 mixture
a-
Chlorobenzaldehyde was compatible with this transformation
and produced (E)-55 in 72% isolated yield. However, 4-
bromobenzaldehyde did not take part in this allylation reaction
and starting material was recovered. Furthermore, 3-
furancarboxaldehyde could be effectively transformed into
g
of (E)-syn and (Z)-syn isomers (Scheme 7). Similarly, the allylation
of benzaldehyde with 16 gave diastereomeric mixture of (E)-46 and
E/Z mixture of 47 in 37% and 15% yields, respectively. Due to the
intrinsic instability of the hypervalent allylsilane species generated
in this system, the current reaction gives homoallylic alcohols as a
mixture of regioisomers. According to the pioneering work of
Hosomi and Sakurai, fluoride-ion-mediated carbonyl allylation
with allylsilanes has also been known to be non-regioselective
[42e44].
desired (E)-homoallylic alcohol 57 in 44% isolated yield, and a,b-
unsaturated cinnamaldehyde led to the formation of the expected
product (E)-58 in 43% yield. Typically, less reactive aliphatic alde-
hydes were reluctant to undergo this reaction, compared to their
aromatic counterparts. Thus, the reaction of isobutyraldehyde gave
59 in 33% yield.
Finally, the scalability of this reaction was demonstrated by a
gram-scale experiment using 60, from which 61 was obtained in
72% yield (Scheme 10).
As in the case of Scheme 4a, the use of 48 possessing a dime-
thylphenylsilyl group instead of a trimethylsilyl group showed a
moderate migration preference for the phenyl group over the
methyl group in the allylation of benzaldehyde. As a result, phenyl
migration product (E)-49 was obtained in 36% yield as a mixture of
diastereomers (1.1:1 dr) along with methyl migration products (E)-
44 (1.8:1 dr) and 45 in 13% and 3% yields, respectively (Scheme 8).
To prevent such regio- and migration-selectivity issues, we
3. Conclusion
We have developed a palladium-catalyzed reaction of readily
accessible
CsF, which induces a previously unprecedented 1,2-shift of a sub-
stituent on silicon in the silylated -allylpalladium intermediates.
g-silylated allyl acetates with water in the presence of
chose substrate 6, which generates a,g-diphenyl allylsilanes in situ,
p
and investigated the scope of the aldehyde partner (Scheme 9).
Reaction with various aromatic aldehydes having different elec-
tronic properties proceeded smoothly to afford (E)-homoallylic
The key to the success of this reaction is the use of an electron-poor
phosphine ligand possessing fluorinated substituents. Theoretical
studies indicate that the 1,2-shift of the substituent on the silicon
atom proceeds through a transition state assisted by the fluoride
anion, where the migration step is rate-determining. In addition,
the HosomieSakurai-type allylation of aldehydes with in situ-
alcohols
49e54
as
mixtures
of
diastereomers.
4-
generated
a,g-disubstituted allylsilanes successfully provided
homoallylic alcohols with good functional group compatibility.
Further investigations to elucidate the reaction mechanism,
including the stereoselectivity of this process, and to develop regio-
and diastereoselective carbonyl allylations, including in an intra-
molecular fashion, are now ongoing in our laboratory.
4. Experimental section
4.1. General experimental information
All reactions were carried out in flame-dried glassware under an
argon atmosphere. Tetrahydrofuran (THF) and 1,4-dioxane were
dried over Na with benzophenone-ketyl intermediate as indicator.
Triethylamine, diisopropylamine, and dichloromethane were pu-
rified by distillation from CaH2. All commercial reagents were used
as received unless otherwise noted. Flash chromatography was
performed with Fuji Silysia PSQ100B (100
matography (TLC) was carried out using Silicagel 70 F254 TLC Plate-
Wako. NMR spectra were recorded on JEOL -GX400 or JNX-
ECX500 spectrometer. For 1H NMR, tetramethylsilane (TMS)
served as internal standard (
follows: chemical shift, integration, multiplicity (s ¼ singlet;
d ¼ doublet; t ¼ triplet; q ¼ quartet; m ¼ multiplet; br ¼ broad),
and coupling constant(s) in (J) Hz. For 13C NMR, CDCl3
mm). Thin layer chro-
a
6
d
¼ 0 ppm) and data are reported as
Scheme 9. Allylation of aldehydes with in situ-generated
from 6.
a,g-diphenyl allylsilanes

8
Y. Horino et al. / Tetrahedron 76 (2020) 131493
(
d
¼ 77.16 ppm) was used as internal standard and spectra were
J ¼ 6.8 Hz, 2H).
obtained with complete proton decoupling. High-resolution mass
(HRMS) spectral data were obtained on a JEOL MStation JMS-700.
4.3.7. (E)-1-(3-Phenylprop-1-en-1-yl)-4-(trifluoromethyl)benzene
(9a) [50]
4.2. General procedure for the synthesis of 2a and 2b (Table 1, entry
7)
(E)-9a and (E)-9b were isolated as an inseparable mixture
(0.5 mmol scale reaction, 113.2 mg, 86%, 9a/9b ¼ 1:2.1, colorless oil,
Rf 0.59: EtOAc/hexane ¼ 1:4). The 1H NMR spectrum of (E)-9a was
identical with that reported in the literature [50]. 1H NMR (CDCl3,
A 10 mL two neck round-bottom flask was charged with
Pd(OAc)2 (5.6 mg, 0.025 mmol), P(4-CF3C6H4)3 (46.7 mg, 0.1 mmol),
and 1,4-dioxane (1.5 mL) under an argon atmosphere. The mixture
was stirred at 80 ꢀC for 0.5 h and cooled to room temperature,
which was then transferred into another 10 mL two neck round-
bottom flask charged with cesium fluoride (227.8 mg, 1.5 mmol).
To this mixture was subsequently added 1 (149.2 mg, 0.5 mmol)
and H2O (10.8 mg, 0.6 mmol) in 1,4-dioxane (1.5 mL) via cannula.
The reaction mixture was stirred at 100 ꢀC for 6 h. Upon completion
of the reaction, the mixture was filtered through a pad of Celite
with diethyl ether (20 mL) as the washing solvent. The filtrate was
washed with saturated NH4Cl (2 ꢂ 20 mL) and brine (2 ꢂ 20 mL).
The combined organic layers were dried over MgSO4 and concen-
trated. The residue was purified by silica gel column chromatog-
raphy (Rf 0.66: EtOAc/hexane ¼ 1:4) to give 2a (56.1 mg, 62%, E/
Z ¼ 1:7.2) and 2b (13.1 mg,14%) as an inseparable mixture (colorless
oil).
400 MHz)
d
7.53 (d, J ¼ 8.4 Hz, 2H), 7.43 (d, J ¼ 8.4 Hz, 2H),
7.37e7.20 (m, 5H), 6.49e6.45 (m, 2H), 3.57 (d, J ¼ 3.6 Hz, 2H).
4.3.8. (E)-1-Cinnamyl-4-(trifluoromethyl)benzene (9b) [50]
The 1H NMR spectrum of (E)-9b was identical with that reported
in the literature [50]. 1H NMR (CDCl3, 400 MHz)
2H), 7.37e7.20 (m, 7H), 6.47 (m, 1H), 6.32 (dt, J ¼ 16.0, 6.8 Hz, 1H),
3.60 (d, J ¼ 6.8 Hz, 2H).
d
7.56 (d, J ¼ 8.0 Hz,
4.3.9. (Z)-1-Methoxy-4-(3-phenylprop-1-en-1-yl)benzene (11a)
[51]
(Z)-11a, (E)-11a, and 11b were isolated as an inseparable
mixture (1 mmol scale reaction, 177.3 mg, 84%, (Z)-11a/(E)-11a/
11b ¼ 1:3.2:2.7, colorless oil, Rf 0.54: EtOAc/hexane ¼ 1:4). The 1H
NMR spectrum of (Z)-11a was identical in the literature [51]. 1H
NMR (CDCl3, 400 MHz)
d 7.36e7.14 (m, 7H), 6.89 (m, 2H), 6.53 (d,
J ¼ 11.6 Hz, 1H), 5.77 (dt, J ¼ 11.6, 7.2 Hz, 1H), 3.81 (s, 3H), 3.67 (dd,
4.3. Characterization data of newly synthesized compounds
J ¼ 1.6, 7.2 Hz, 2H).
4.3.1. (Z)-1-(But-2-en-1-yl)naphthalene (2a) [45]
4.3.10. (E)-1-Methoxy-4-(3-phenylprop-1-en-1-yl)benzene (11a)
[51]
The 1H NMR spectrum of (Z)-2a was identical with that reported
in the literature [45]. 1H NMR (CDCl3, 400 MHz)
7.90e7.88 (m, 1H), 7.77 (m, 1H), 7.61e7.36 (m, 4H), 5.81e5.55 (m,
2H), 3.88 (d, J ¼ 5.2 Hz, 2H), 1.85 (d, J ¼ 5.6 Hz, 3H).
d
8.08 (m, 1H),
The 1H NMR spectrum of (E)-11a was identical with that re-
ported in the literature [51]. 1H NMR (CDCl3, 400 MHz)
d 7.36e7.14
(m, 7H), 6.89 (m, 2H), 6.45e6.38 (m, 1H), 6.21 (dt, J ¼ 16.0, 7.2 Hz,
1H), 3.79 (s, 3H), 3.53 (d, J ¼ 6.8 Hz, 2H).
4.3.2. (E)-1-(But-2-en-1-yl)naphthalene (2a) [46]
The 1H NMR spectrum of (E)-2a was identical with that reported
4.3.11. (E)-1-Cinnamyl-4-methoxybenzene (11b) [52]
in the literature [46]. 1H NMR (CDCl3, 400 MHz)
d
8.08 (m, 1H), 7.88
The 1H NMR spectrum of (E)-11b was identical with that re-
(m, 1H), 7.77 (m, 1H), 7.61e7.36 (m, 4H), 5.81e5.55 (m, 2H), 3.81 (d,
J ¼ 6.0 Hz, 2H), 1.72 (dd, J ¼ 1.2, 6.8 Hz, 3H).
ported in the literature [52]. 1H NMR (CDCl3, 400 MHz)
d 7.36e7.14
(m, 7H), 6.89 (m, 2H), 6.45e6.38 (m, 1H), 6.33 (dt, J ¼ 15.6, 6.4 Hz,
1H), 3.79 (s, 3H), 3.49 (d, J ¼ 6.4 Hz, 2H).
4.3.3. (E)-1-(But-1-en-1-yl)naphthalene (2b) [47]
The 1H NMR spectrum of (E)-2b was identical with that reported
4.3.12. (Z)-2-(3-Phenylprop-1-en-1-yl)furan (13a) [50]
in the literature [47]. 1H NMR (CDCl3, 400 MHz)
d
8.18 (d, J ¼ 8.0 Hz,
(Z)-13a, (E)-13a, and 13b were isolated as an inseparable
mixture (0.5 mmol scale reaction, 57.3 mg, 64%, (Z)-13a/(E)-13a/
13b ¼ 1:1:3.2, colorless oil, Rf 0.59: EtOAc/hexane ¼ 1:4). The 1H
NMR spectrum of (Z)-13a was identical with that reported in the
1H), 7.90e7.36 (m, 6H), 7.16 (d, J ¼ 16.0 Hz, 1H), 6.32 (dt, J ¼ 16.0,
6.4 Hz, 1H), 2.43e2.35 (m, 2H), 1.22 (t, J ¼ 7.6 Hz, 3H).
4.3.4. (E)-1-(3-(trimethylsilyl)prop-1-en-1-yl)naphthalene (2c)
[48]
literature [50]. 1H NMR (CDCl3, 400 MHz)
d 7.41e7.19 (m, 6H),
6.42e6.25 (m, 3H), 5.71 (dt, J ¼ 11.6, 7.6 Hz, 1H), 3.84 (dd, J ¼ 0.8,
The 1H NMR spectrum of (E)-2c was identical with that reported
7.6 Hz, 2H).
in the literature [48]. 1H NMR (CDCl3, 400 MHz)
d 8.13 (dm,
J ¼ 8.0 Hz, 1H), 7.83 (dm, J ¼ 8.0 Hz, 1H), 7.72 (dm, J ¼ 8.0 Hz, 1H),
7.53e7.40, 6.96 (d, J ¼ 16.0 Hz, 1H), 6.26 (dt, J ¼ 16.0, 8.0 Hz, 1H),
1.81 (dd, J ¼ 1.2, 8.0 Hz, 1H), 0.11 (2, 9H).
4.3.13. (E)-2-(3-Phenylprop-1-en-1-yl)furan (13a) [50]
The 1H NMR spectrum of (E)-13a was identical with that re-
ported in the literature [50]. 1H NMR (CDCl3, 400 MHz)
d 7.41e7.19
(m, 6H), 6.42e6.25 (m, 3H), 6.15 (d, J ¼ 3.2 Hz, 1H), 3.51 (d,
4.3.5. (Z)-1,3-Diphenylpropene (7a) [49]
J ¼ 6.8 Hz, 2H).
(Z)-7a and (E)-7a were isolated as an inseparable mixture
(0.5 mmol scale reaction, 73.7 mg, 76%, E/Z ¼ 17.5:1, colorless oil, Rf
0.23: hexane). The 1H NMR spectrum of (Z)-7a was identical with
that reported in the literature [49]. 1H NMR (CDCl3, 400 MHz)
4.3.14. (E)-2-Cinnamylfuran (13b) [52]
The 1H NMR spectrum of (E)-13b was identical with that re-
ported in the literature [52]. 1H NMR (CDCl3, 400 MHz)
d 7.41e7.19
d
7.39e7.20 (m, 10H), 6.61 (d, J ¼ 11.6 Hz, 1H), 5.88 (dt, J ¼ 11.6,
(m, 6H), 6.49 (d, J ¼ 15.6 Hz, 1H), 6.42e6.25 (m, 2H), 6.07 (dd,
8.0 Hz, 1H), 3.70 (d, J ¼ 8.0 Hz, 2H).
J ¼ 0.8, 3.2 Hz, 1H), 3.55 (d, J ¼ 6.8 Hz, 2H).
4.3.6. (E)-1,3-Diphenylpropene (7a) [49]
4.3.15. (Z)-2-(3-Phenylprop-1-en-1-yl)thiophene (15a) [53]
(Z)-15a, (E)-15a, and 15b were isolated as an inseparable
mixture (0.5 mmol scale reaction, 61.5 mg, 62%, (Z)-15a/(E)-15a/
15b ¼ 1:1.2:8.3, yellow solid, Rf 0.68: EtOAc/hexane ¼ 1:4). The 1H
The 1H NMR spectrum of (E)-7a was identical with that reported
in the literature [49]. 1H NMR (CDCl3, 400 MHz)
10H), 6.48 (d, J ¼ 16.0 Hz, 1H), 6.38 (dt, J ¼ 16.0, 6.8 Hz, 1H), 3.57 (d,
d
7.39e7.20 (m,

Y. Horino et al. / Tetrahedron 76 (2020) 131493
9
NMR spectrum of (Z)-15a was identical with that reported in the
literature [53]. 1H NMR (CDCl3, 400 MHz)
7.39e7.20 (m, 5H), 7.03
7.56e7.32 (m, 5H), 5.64e5.52 (m, 2H), 3.83 (d, J ¼ 6.4 Hz, 2H), 2.25
(quint, J ¼ 7.2 Hz, 2H), 1.06 (t, J ¼ 7.2 Hz, 3H); For (Z)-24a and (E)-
d
(m, 1H), 6.97e6.87 (m, 2H), 6.66 (d, J ¼ 10.8 Hz, 1H), 5.80e5.73 (m,
24a: 13C NMR(CDCl3, 100 MHz)
d 137.4, 137.3, 134.02 (two peaks),
1H), 3.79 (d, J ¼ 7.2 Hz, 2H).
133.98, 133.95, 132.9 (two peaks), 132.1, 128.83, 128.76, 127.4, 127.3,
126.9, 126.8, 126.1, 125.9 (two peaks), 125.8 (two peaks), 125.6,
124.2, 124.0, 36.2, 31.0, 25.7, 20.9, 14.4, 13.9; HRMS (EI): found
196.1252. C15H16 requires 196.1252.
4.3.16. (E)-2-(3-Phenylprop-1-en-1-yl)thiophene (15a) [53]
The 1H NMR spectrum of (E)-15a was identical with that re-
ported in the literature [53]. 1H NMR (CDCl3, 400 MHz)
d 7.39e7.20
(m, 5H), 7.05e7.00 (m, 1H), 6.97e6.87 (m, 2H), 6.55 (d, J ¼ 16.8 Hz,
4.3.25. (E)-1-(Pent-2-en-1-yl)naphthalene (24a)
1H), 6.23 (m, 1H), 3.51 (d, J ¼ 6.8 Hz, 2H).
1H NMR (CDCl3, 400 MHz)
d 8.04 (m, 1H), 7.84 (m, 1H), 7.72 (m,
1H), 7.56e7.32 (m, 5H), 5.73e5.66 (m, 2H), 3.77 (d, J ¼ 6.4 Hz, 2H),
4.3.17. (E)-2-Cinnamylthiophene (15b) [52]
2.03 (dquint, J ¼ 1.2, 7.2 Hz, 2H), 0.97 (t, J ¼ 7.2 Hz, 3H).
The 1H NMR spectrum of (E)-15b was identical with that re-
ported in the literature [52]. 1H NMR (CDCl3, 400 MHz)
d
7.39e7.20
4.3.26. (E)-1-(Pent-1-en-1-yl)naphthalene (24b) [59]
(m, 5H), 7.17e7.16 (m, 1H), 6.95 (m, 1H), 6.88 (m, 1H), 6.51 (d,
J ¼ 16.0 Hz, 1H), 6.37 (m, 1H), 3.74 (d, J ¼ 6.4 Hz, 2H).
The 1H NMR spectrum of (E)-24b was identical with that re-
ported in the literature [59]. 1H NMR (CDCl3, 400 MHz)
d 8.12 (d,
J ¼ 7.2 Hz, 1H), 7.84 (m, 1H), 7.72 (m, 1H), 7.55 (d, J ¼ 7.6 Hz, 1H),
7.53e7.32 (m, 3H), 7.11 (d, J ¼ 15.2 Hz, 1H), 6.23 (dt, J ¼ 15.2, 7.2 Hz,
1H), 2.34e2.30 (m, 2H), 1.57 (sext, J ¼ 7.2 Hz, 2H), 1.01 (t, J ¼ 7.2 Hz,
3H).
4.3.18. (Z)-Pent-2-en-1-ylbenzene (17a) [54]
(Z)-17a, (E)-17a, and 17b were isolated as an inseparable
mixture (0.5 mmol scale, reaction, 34.8 mg, 48%, (Z)-17a/(E)-17a/
17b ¼ 3.3:1:2, colorless oil, Rf 0.72: EtOAc/hexane ¼ 1:4). The 1H
NMR spectrum of (Z)-17a was identical with that reported in the
4.3.27. 1-Butylnaphthalene [60]
literature [54]. 1H NMR (CDCl3, 400 MHz)
d
7.36e7.19 (m, 5H),
2a, 2b, (Z)-1-(penta-2,4-dien-1-yl)naphthalene (27a), and (E)-
1-(penta-1,4-dien-1-yl)naphthalene (27b) were isolated in as an
inseparable mixture. The hydrogenation of given alkenes was per-
formed to identify the products. To a solution of 2 and 27 (160.0 mg)
in ethyl acetate (3 mL) was added Pd/C (106.4 mg). The atmosphere
in the flask was replaced to hydrogen under balloon pressure, and
the mixture was vigorously stirred at room temperature for 12 h.
Upon completion, the mixture was filtered through a pad of Celite
to afford crude material, which was purified by silica gel column
chromatography to give 1-butylnaphthalene (37%) and 1-
pentylnaphthalene (49%) as an inseparable mixture (165.1 mg, Rf
0.65: EtOAc/hexane ¼ 1:4, colorless oil).
5.58e5.51 (m, 2H), 3.41 (d, J ¼ 6.0 Hz, 2H), 2.22e2.02 (m, 2H),
1.05e0.94 (m, 3H).
4.3.19. (E)-Pent-2-en-1-ylbenzene (17a) [55]
The 1H NMR spectrum of (E)-17a was identical with that re-
ported in the literature [55]. 1H NMR (CDCl3, 400 MHz)
d 7.36e7.19
(m, 5H), 5.58e5.51 (m, 2H), 3.33 (d, J ¼ 3.6 Hz, 2H), 2.22e2.02 (m,
2H), 1.05e0.94 (m, 3H).
4.3.20. (E)-Pent-1-en-1-ylbenzene (17b) [56]
The 1H NMR spectrum of (E)-17b was identical with that re-
ported in the literature [56]. 1H NMR (CDCl3, 400 MHz)
d
7.36e7.19
1-Butylnaphthalene [60]: The 1H NMR spectrum of 1-
butylnaphthalene was identical with that reported in the litera-
(m, 5H), 6.39 (d, J ¼ 15.6 Hz, 1H), 6.23 (dt, J ¼ 15.6, 6.8 Hz, 1H),
2.22e2.02 (m, 2H), 1.55e1.46 (m, 2H), 1.05e0.94 (m, 3H).
ture [57]. 1H NMR (CDCl3, 400 MHz)
d
8.03 (d, J ¼ 7.6 Hz, 1H), 7.82
(d, J ¼ 8.0 Hz, 1H), 7.68 (d, J ¼ 8.0 Hz, 1H), 7.50e7.42 (m, 2H), 7.36 (d,
J ¼ 7.6 Hz, 1H), 7.29 (d, J ¼ 6.8 Hz, 1H), 3.05 (t, J ¼ 7.6 Hz, 2H),
1.78e1.68 (m, 2H), 1.49e1.33 (m, 2H), 0.96 (t, J ¼ 7.6 Hz, 3H).
4.3.21. (Z)-1-(3-Phenylallyl)naphthalene (21a)
(Z)-21a, (E)-21a, and 21b were isolated as an inseparable
mixture (1 mmol scale reaction, 82.6 mg, 35%, (Z)-21a/(E)-21a/
21b ¼ 1:9.2:6.1, yellow solid, Rf 0.57: EtOAc/hexane ¼ 1:4); Yellow
4.3.28. 1-Pentylnaphthalene [61]
solid; 1H NMR (CDCl3, 400 MHz)
d
8.08 (m, 1H), 7.85e7.13 (m, 11H),
The 1H NMR spectrum of 1-pentylnaphthalene was identical
6.61 (d, J ¼ 11.6 Hz, 1H), 5.91 (dt, J ¼ 11.6, 7.2 Hz, 1H), 4.08 (d,
with that reported in the literature [58]. 1H NMR (CDCl3, 400 MHz)
J ¼ 7.2 Hz, 2H); 13C NMR(CDCl3, 100 MHz)
d
137.4,136.9,135.1,134.8,
d
8.03 (d, J ¼ 7.6 Hz, 1H), 7.82 (d, J ¼ 8.0 Hz, 1H), 7.68 (d, J ¼ 8.0 Hz,
134.5, 130.9, 130.7, 130.3, 128.2, 128.0, 127.8, 127.0, 32.4; HRMS (EI):
found 244.1251. C19H16 requires 244.1252.
1H), 7.50e7.42 (m, 2H), 7.37 (t, J ¼ 7.6 Hz, 1H), 7.29 (d, J ¼ 6.8 Hz,
1H), 3.04 (t, J ¼ 7.6 Hz, 2H), 1.78e1.68 (m, 2H), 1.49e1.33 (m, 4H),
0.90 (t, J ¼ 6.8 Hz, 3H).
4.3.22. (E)-1-(3-Phenylallyl)naphthalene (21a) [57]
The 1H NMR spectrum of (E)-21a was identical with that re-
4.3.29. (E)-1-(4-Phenyl-2-buten-1-yl)naphthalene (29a)
ported in the literature [57]. 1H NMR (CDCl3, 400 MHz)
d 8.08 (m,
1H), 7.85e7.13 (m, 11H), 6.49 (dd, J ¼ 5.6, 16.0 Hz, 1H), 6.43 (d,
(Z)-29a, (E)-29a, and 29b were isolated as an inseparable
mixture (0.5 mmol scale reaction, 58.4 mg, 46%, (Z)-29a/(E)-
29a/29b ¼ 2.6:1.3:1, colorless oil, Rf 0.60: EtOAc/hexane ¼ 1:4).
The alkene stereochemistry was determined by the analysis of
nOe experiments. For details, see the supplementary material.
J ¼ 16.0 Hz, 1H), 3.96 (d, J ¼ 4.4 Hz, 2H).
4.3.23. (E)-1-(3-Phenylprop-1-en-1-yl)naphthalene (21b) [58]
The 1H NMR spectrum of (E)-21b was identical with that re-
ported in the literature [58]. 1H NMR (CDCl3, 400 MHz)
d 8.08 (m,
1H), 7.85e7.13 (m, 12H), 6.36 (dt, J ¼ 15.2, 6.8 Hz, 1H), 3.64 (d,
(Z)-isomer: 1H NMR (CDCl3, 400 MHz)
d 8.03 (m, 1H), 7.84 (m,
J ¼ 6.8 Hz, 2H).
1H), 7.74 (m, 1H), 7.52e7.15 (m, 9H), 5.84e5.66 (m, 2H), 3.95 (d,
J ¼ 5.6 Hz, 2H), 3.61 (d, J ¼ 6.0 Hz, 2H); For (E)- and (Z)-isomers, 13
C
4.3.24. (Z)-1-(Pent-2-en-1-yl)naphthalene (24a)
NMR (CDCl3, 100 MHz) d 140.84, 140.80, 136.93, 136.89, 134.00,
(Z)-24a, (E)-24a, and 24b were isolated as an inseparable
mixture (0.5 mmol scale reaction, 81.0 mg, 82%, (Z)-24a/(E)-24a/
24b ¼ 2.1:1:1, colorless oil, Rf 0.72: EtOAc/hexane ¼ 1:4). 1H NMR
133.97, 132.1, 131.3, 130.8, 129.5, 129.0, 128.88, 128.80, 128.64,
128.58, 128.48, 127.0, 126.2, 126.14, 126.08, 125.99, 125.7, 125.6,
124.3, 124.0, 39.1, 36.3, 33.8, 31.1.
(CDCl3, 400 MHz)
d
8.06e8.01 (m, 1H), 7.84 (m, 1H), 7.72 (m, 1H),
Characteristic peaks of (E)-isomer: 1H NMR (CDCl3, 400 MHz)

10
Y. Horino et al. / Tetrahedron 76 (2020) 131493
d
3.82 (d, J ¼ 6.4 Hz, 2H), 3.36 (d, J ¼ 6.4 Hz, 2H).
(1.0 mL) via cannula. The reaction mixture was stirred at 100 ꢀC
for 2.5 h. Upon completion of the reaction, the mixture was filtered
through a pad of Celite with diethyl ether (20 mL) as the washing
solvent. The filtrate was washed with saturated NH4Cl (2 ꢂ 20 mL)
and brine (2 ꢂ 20 mL). The combined organic layers were dried over
MgSO4 and concentrated. The residue was purified by silica gel
column chromatography (Rf 0.33: EtOAc/hexane ¼ 1:4) to give 49
(127.7 mg, 85%, syn/anti ¼ 52:48) as an inseparable mixture (yellow
oil).
4.3.30. (E)-1-(4-Phenyl-1-buten-1-yl)naphthalene (29b) [62]
The 1H NMR spectrum of (E)-29b was identical with that re-
ported in the literature [62]. 1H NMR (CDCl3, 400 MHz)
d 8.03 (m,
1H), 7.84 (m, 1H), 7.72 (d, J ¼ 8.4 Hz, 1H), 7.52e7.15 (m, 9H), 7.09 (d,
J ¼ 15.6 Hz, 1H), 6.24 (dt, J ¼ 15.6, 6.8 Hz,1H), 2.87 (t, J ¼ 8.0 Hz, 2H),
2.65 (dq, J ¼ 0.8, 7.2 Hz, 2H); 13C NMR (CDCl3, 100 MHz)
d 141.8,
135.7, 133.7, 133.3, 130.2, 128.7, 128.52, 128.0, 127.5, 126.04, 125.91,
125.8, 124.1, 123.7, 36.0, 35.3.
4.5. Characterization data of newly synthesized compounds
4.3.31. 1-(Hexa-2,5-dien-1-yl)naphthalene (31a)
4.5.1. (E)-1,2,4-Triphenylbut-3-en-1-ol (49)
(Z)-31a, (E)-31a, and 31b were isolated as an inseparable
mixture (1 mmol scale reaction, 105.0 mg, 49%, (Z)-31a/(E)-31a/
31b ¼ 1.8:1:1, yellow oil, Rf 0.66: EtOAc/hexane ¼ 1:4). The
alkene stereochemistry was determined by the analysis of nOe
experiments. For details, see the supplementary material.
syn-49 and anti-49 were isolated as an inseparable mixture
(116.8 mg, 85%, colorless solid, Rf 0.46: EtOAc/hexane ¼ 3:7). The 1H
NMR spectrum of anti-49 was identical with that reported in the
literature [65]. anti-isomer: 1H NMR (CDCl3, 400 MHz)
d 7.41e7.14
(m, 15H), 6.63 (dd, J ¼ 7.9, 15.8 Hz, 1H), 6.53 (d, J ¼ 15.8 Hz, 1H), 4.94
(dd, J ¼ 2.4, 7.9 Hz, 1H), 3.73 (t, J ¼ 7.9 Hz, 1H), 2.37 (d, J ¼ 2.4 Hz,
For (E)- and (Z)-isomers: 13C NMR (CDCl3, 100 MHz)
d
137.2,
1H); 13C NMR (CDCl3, 100 MHz)
d 142.0, 140.9, 137.0, 133.5, 129.2,
137.0, 136.9, 136.7, 133.98, 133.95, 132.1, 131.3, 129.8, 129.6, 129.2,
128.84, 128.78, 128.0, 126.9, 126.2, 125.94, 125.87, 124.2, 124.0, 36.8,
36.2, 31.9, 31.0.
128.9, 128.6, 128.52, 128.0, 127.6, 127.5, 126.8, 126.4, 77.8, 58.4.
syn-isomer: 1H NMR (CDCl3, 400 MHz)
d
7.41e7.14 (m,15H), 6.29
(dd, J ¼ 7.9, 15.8 Hz, 1H), 6.18 (d, J ¼ 15.8 Hz, 1H), 5.00 (dd, J ¼ 3.0,
7.9 Hz, 1H), 3.78 (t, J ¼ 7.9 Hz, 1H), 2.05 (d, J ¼ 3.0 Hz, 1H); 13C NMR
4.3.32. (E)-1-(Hexa-1,5-dien-1-yl)naphthalene (31b) [63]
(CDCl3, 100 MHz) d 142.0, 140.5, 137.3, 132.3, 129.5, 128.9, 128.55,
The 1H NMR spectrum of (E)-31b was identical with that re-
128.3, 127.9, 127.3, 127.2, 127.0, 126.2, 77.9, 57.8.
ported in the literature [63]. 1H NMR (CDCl3, 400 MHz)
d 8.12 (d,
J ¼ 8.0 Hz, 1H), 7.84 (m, 1H), 7.72 (d, J ¼ 8.0 Hz, 1H), 7.55e7.44 (m,
4.5.2. (E)-2-Methyl-1,4-diphenylbut-3-en-1-ol (44) [44]
3H), 7.13 (d, J ¼ 15.6 Hz, 1H), 6.24 (dt, J ¼ 6.8, 16.0 Hz, 1H), 5.83 (m,
1H), 5.05e5.02 (m, 3H), 2.47e2.41 (m, 2H), 2.35e2.29 (m, 2H); 13
C
44 and 45 were isolated as an inseparable mixture (74.7 mg,
60%, yellow oil, Rf 0.40 and 0.38: EtOAc/hexane ¼ 1:4).
NMR (CDCl3, 100 MHz)
d 138.2, 135.7, 133.7, 133.5, 128.6, 127.6,
127.4, 125.8, 125.7, 125.6, 124.1, 123.7, 115.2, 33.7, 32.9.
The 1H NMR spectrum of syn-(E)-44 was identical with that
4.3.33. 1-(5-Phenylpent-2-en-4-yn-1-yl)naphthalene (33a) [64]
reported in the literature [44].
(Z)-33a, (E)-33a, and 33b were isolated as an inseparable
mixture (0.4 mmol scale reaction, 69.0 mg, 68%, (Z)-33a/(E)-33a/
33b ¼ 4:1:26, yellow oil, Rf 0.60: EtOAc/hexane ¼ 1:4). The 1H NMR
spectrum of (Z)-33a was identical with that reported in the litera-
ture [64]. Characteristic peaks of (Z)-isomer: 1H NMR (CDCl3,
syn-(E)-44: 1H NMR (CDCl3, 400 MHz)
d 7.37e7.17 (m, 10H), 6.42
(d, J ¼ 16.0 Hz, 1H), 6.16 (dd, J ¼ 8.0, 15.6 Hz, 1H), 4.70 (d, J ¼ 5.2 Hz,
1H), 2.77 (sext, J ¼ 6.8 Hz, 1H), 2.16 (br s, 1H), 1.14 (d, J ¼ 6.8 Hz, 3H).
The 1H NMR spectrum of anti-(E)-44 was identical with that
reported in the literature [44].
500 MHz)
d
6.17 ( td, J ¼ 7.0, 10.5 Hz, 1H), 5.83 (dt, J ¼ 10.5, 1.5 Hz,
Characteristic peaks of anti-(E)-44: 1H NMR (CDCl3, 400 MHz)
1H), 4.15 (dd, J ¼ 1.5, 7.0 Hz, 2H).
d
6.56 (d, J ¼ 16.0 Hz, 1H), 6.23 (dd, J ¼ 16.1, 8.4 Hz, 1H), 4.47 (d,
Characteristic peaks of (E)-isomer: 1H NMR (CDCl3, 500 MHz)
J ¼ 8.0 Hz, 1H), 2.69 (sext, J ¼ 7.2 Hz, 1H), 2.23 (br s, 1H), 1.00 (d,
J ¼ 7.2 Hz, 3H).
d
6.54 ( td, J ¼ 6.5, 16.0 Hz, 1H), 5.72 (dt, J ¼ 16.0, 1.5 Hz, 1H), 3.94
(dd, J ¼ 1.5, 6.5 Hz, 2H).
4.5.3. (Z)-1,2-Diphenylpent-3-en-1-ol (45) [44]
4.3.34. (E)-1-(5-phenylpent-1-en-4-yn-1-yl)naphthalene (33b)
The 1H NMR spectrum of syn-(Z)-45 was identical with that
reported in the literature [44].
1H NMR (CDCl3, 500 MHz)
d
8.14 (d, J ¼ 8.5 Hz, 1H), 7.85 (dm,
J ¼ 8.5 Hz, 1H), 7.77 (d, J ¼ 8.5 Hz, 1H), 7.58 (d, J ¼ 7.5 Hz, 1H),
7.52e7.41 (m, 6H), 7.34e7.28 (m, 3H), 6.26 (dt, J ¼ 5.5, 15.0 Hz, 1H),
Characteristic peaks of syn-(Z)-45: 1H NMR (CDCl3, 400 MHz)
d
5.65 (tq, J ¼ 10.8, 1.6 Hz, 1H), 5.45 (dqd, J ¼ 10.8, 6.8, 0.8 Hz, 1H),
3.47 (dd, J ¼ 2.0, 5.5 Hz, 2H); 13C NMR (CDCl3, 100 MHz)
d
135.1,
4.85 (d, J ¼ 8.4 Hz, 1H), 3.95 (t, J ¼ 9.2 Hz, 1H), 2.07 (br s, 1H), 1.36
(dd, J ¼ 6.8, 2.0 Hz, 1H).
133.7,131.8,131.3,128.9,128.6,128.4,128.0,127.9,127.5,126.1,125.9,
125.8, 124.05, 124.02, 123.8, 86.9, 83.3, 23.6; HRMS (EI): found
268.1250. C21H16 requires 268.1252.
Characteristic peaks of minor isomer of 45: 1H NMR (CDCl3,
400 MHz)
d
5.60 (ddq, J ¼ 15.2, 8.0, 1.6 Hz, 1H), 5.31 (dq, J ¼ 15.2,
6.8 Hz, 1H). anti-(Z)-45, anti-(E)-45 were known compound [44].
4.4. General procedure for allylation of aldehydes with in situ
generated
a,
g
-disubstituted allylsilanes
4.5.4. (E)-1,4-Diphenyl-2-ethyl-but-3-en-1-ol (46)
46 and 47 were isolated as an inseparable mixture (64.8 mg,
52%, yellow oil, Rf 0.40 and 0.38: EtOAc/hexane ¼ 1:4).
A 10 mL two neck round-bottom flask was charged with
Pd(OAc)2 (2.8 mg, 0.0125 mmol), P(4-CF3C6H4)3 (23.3 mg,
0.05 mmol), and 1,4-dioxane (1.0 mL) under an argon atmosphere.
The mixture was stirred at 80 ꢀC for 0.5 h and cooled to room
temperature, which was then transferred into another 10 mL two
neck round-bottom flask charged with cesium fluoride (227.8 mg,
1.5 mmol). To this mixture was subsequently added 6 (217.3 mg,
0.5 mmol) and benzaldehyde (191.0 mg, 1.8 mmol) in 1,4-dioxane
major isomer: 1H NMR (CDCl3, 400 MHz)
d 7.40e7.20 (m, 10H),
6.37 (d, J ¼ 15.6 Hz, 1H), 5.89 (dd, J ¼ 9.6, 16.0 Hz, 1H), 4.73 (t,
J ¼ 5.2 Hz, 1H), 2.49 (ddt, J ¼ 4.4, 5.6, 9.6 Hz, 1H), 2.06 (br s, 1H),
1.42e1.22 (m, 2H), 0.90 (t, J ¼ 7.6 Hz, 3H); 13C NMR (CDCl3,
100 MHz) d 142.6,137.5, 132.7,130.2,128.6,128.2,127.6, 127.3, 126.8,
77.2, 52.6, 23.3, 12.2.
minor isomer: 1H NMR (CDCl3, 400 MHz)
d 7.40e7.20 (m, 10H),

Y. Horino et al. / Tetrahedron 76 (2020) 131493
11
6.53 (d, J ¼ 16.0 Hz, 1H), 6.06 (dd, J ¼ 9.2, 16.0 Hz, 1H), 4.51 (dd,
J ¼ 2.4, 8.0 Hz,1H), 2.37 (ddm, J ¼ 4.4, 9.6 Hz,1H), 2.17 (br s,1H),1.69
(dm, J ¼ 7.6 Hz, 2H), 0.83 (t, J ¼ 7.6 Hz, 3H); 13C NMR (CDCl3,
6.24 (dd, J ¼ 8.0, 16.0 Hz, 1H), 6.17 (d, J ¼ 16.0 Hz, 1H), 5.93 (d,
J ¼ 1.6 Hz,1H), 5.92 (d, J ¼ 1.6 Hz,1H), 4.88 (d, J ¼ 8.0 Hz,1H), 3.71 (t,
J ¼ 8.0 Hz, 1H), 1.97 (s, 1H); 13C NMR (CDCl3, 100 MHz)
d 147.8, 147.2,
100 MHz)
d
142.7, 137.2, 134.1, 130.7, 128.7, 128.4, 128.1, 127.8, 127.1,
140.6, 137.3, 136.0, 132.2, 129.5, 128.9, 128.8, 128.5, 127.3, 127.2,
126.2, 120.7, 107.9, 107.9, 107.1, 77.5, 57.8.
126.4, 77.3, 54.0, 24.1, 12.1.
4.5.5. 1,2-Diphenylhex-3-en-1-ol (47)
4.5.9. (E)-1-(4-Methoxycarbonylphenyl)-2,4-diphenylbut-3-en-1-
ol (53)
The 1H NMR spectrum of syn-(E)-47 was identical with that
reported in the literature [66].
syn-53 and anti-53 were isolated as an inseparable mixture
(145.8 mg, 82%, colorless solid, Rf 0.35: EtOAc/hexane ¼ 3:7). The 1H
NMR spectrum of anti-53 was identical with that reported in the
Characteristic peaks of syn-(E)-47: 1H NMR (CDCl3, 400 MHz)
d
5.56e5.46 (m,1H), 5.31e5.22 (m,1H), 4.85 (dd, J ¼ 3.2, 8.0 Hz,1H),
3.55 (t, J ¼ 8.0 Hz, 1H), 1.95 (d, J ¼ 3.2 Hz, 1H), 0.80 (t, J ¼ 7.6 Hz, 3H).
literature [68]. anti-isomer: 1H NMR (CDCl3, 400 MHz)
d 7.89 (d,
Characteristic peaks of syn-(Z)-47: 1H NMR (CDCl3, 400 MHz)
J ¼ 7.9 Hz, 2H), 7.39e7.11 (m, 12H), 6.61 (dd, J ¼ 7.9, 15.8 Hz, 1H),
6.53 (d, J ¼ 15.8 Hz, 1H), 4.97 (dd, J ¼ 2.4, 7.9 Hz, 1H), 3.88 (s, 3H),
3.68 (t, J ¼ 7.9 Hz, 1H), 2.58 (d, J ¼ 2.4 Hz, 1H); 13C NMR (CDCl3,
d
5.56e5.46 (m,1H), 5.31e5.22 (m,1H), 4.82 (dd, J ¼ 3.2, 9.2 Hz,1H),
3.89 (t, J ¼ 9.2 Hz, 1H), 1.92 (d, J ¼ 3.2 Hz, 1H), 0.63 (t, J ¼ 7.6 Hz, 3H).
anti-(E)-47 and anti-(Z)-47 were known compounds [67].
100 MHz) d 167.0, 147.2, 140.4,136.8,133.8 (two peaks),129.3,129.2,
128.8, 128.5, 128.4, 127.7, 127.0, 126.4, 126.2, 77.3, 58.4, 52.1.
4.5.6. (E)-1-(4-Methoxyphenyl)-2,4-diphenylbut-3-en-1-ol (50)
syn-50 and anti-50 were isolated as an inseparable mixture
(116.9 mg, 71%, yellow oil, Rf 0.38: EtOAc/hexane ¼ 3:7). The 1H
NMR spectrum of anti-50 was identical with that reported in the
syn-isomer: 1H NMR (CDCl3, 400 MHz)
d
7.98 (d, J ¼ 7.9 Hz, 2H),
7.39e7.11 (m, 12H), 6.30 (dd, J ¼ 7.9, 15.8 Hz, 1H), 6.22 (d,
J ¼ 15.8 Hz, 1H), 5.05 (dd, J ¼ 3.2, 7.9 Hz, 1H), 3.90 (s, 3H), 3.77 (t,
J ¼ 7.9 Hz, 1H), 2.27 (d, J ¼ 3.2 Hz, 1H); 13C NMR (CDCl3, 100 MHz)
literature [68]. anti-isomer: 1H NMR (CDCl3, 400 MHz)
d
7.38e7.08
d 167.0, 147.2, 139.9, 137.0, 132.6 (two peaks), 128.9, 128.6, 128.5,
(m, 12H), 6.74 (dm, J ¼ 8.8 Hz, 2H), 6.61 (dd, J ¼ 8.8, 16.0, 1H), 6.53
(d, J ¼ 16.0, 1H), 4.88 (dd, J ¼ 2.4, 8.0, 1H), 3.73 (s, 3H), 3.68 (t,
J ¼ 8.0 Hz, 1H), 2.28 (d, J ¼ 2.4 Hz, 1H); 13C NMR (CDCl3, 100 MHz)
127.5, 127.3, 127.0, 126.7, 77.4, 57.7, 52.1.
4.5.10. (E)-1-(4-Cyanophenyl)-2,4-diphenylbut-3-en-1-ol (54)
syn-54 and anti-54 were isolated as an inseparable mixture
(87.7 mg, 54%, yellow solid, Rf 0.45: EtOAc/hexane ¼ 3:7). The 1H
NMR spectrum of anti-54 was identical with that reported in the
d
158.9, 141.0, 137.1, 134.19, 133.3, 129.5, 128.6, 128.5 (two peaks),
127.9, 127.6, 126.7, 126.4, 113.7, 77.3, 58.5, 55.2.
syn-isomer: 1H NMR (CDCl3, 400 MHz)
d
7.38e7.08 (m, 12H),
6.85 (dm, J ¼ 8.8 Hz, 2H), 6.25 (dd, J ¼ 8.0, 16.0 Hz, 1H), 6.17 (d,
J ¼ 16.0 Hz, 1H), 4.93 (dd, J ¼ 2.4, 8.0 Hz, 1H), 3.78 (s, 3H), 3.75 (t,
J ¼ 8.0 Hz, 1H), 1.95 (d, J ¼ 2.4 Hz, 1H); 13C NMR (CDCl3, 100 MHz)
literature [68]. anti-isomer: 1H NMR (CDCl3, 400 MHz)
d 7.47 (d,
J ¼ 8.8 Hz, 2H), 7.38e7.17 (m, 10H), 7.09 (d, J ¼ 7.2 Hz, 2H), 6.57 (dd,
J ¼ 7.2, 15.6 Hz, 1H), 6.52 (d, J ¼ 15.6 Hz, 1H), 4.95 (d, J ¼ 7.2 Hz, 1H),
3.61 (t, J ¼ 7.2 Hz, 1H), 2.50 (s, 1H); 13C NMR (CDCl3, 100 MHz)
d
159.2, 140.7, 137.3, 134.18, 132.2, 129.7, 128.94, 128.90, 128.5, 128.2,
127.3, 127.2, 126.2, 113.4, 77.4, 57.8, 55.3.
d 147.4, 140.0, 136.6, 134.4, 131.9 (two peaks), 128.86, 128.3, 128.0,
127.5, 127.3, 126.5, 119.0, 111.3, 77.16, 58.7.
4.5.7. (E)-1-(2-Methoxyphenyl)-2,4-diphenylbut-3-en-1-ol (51)
syn-51 and anti-51 were isolated as an inseparable mixture
(140.4 mg, 85%, yellow oil, Rf 0.38: EtOAc/hexane ¼ 3:7). The 1H
NMR spectrum of anti-51 was identical with that reported in the
syn-isomer: 1H NMR (CDCl3, 400 MHz)
d
7.57 (d, J ¼ 8.0 Hz, 2H),
7.38e7.17 (m,12H), 6.27 (dd, J ¼ 8.0,15.6 Hz,1H), 6.19 (d, J ¼ 15.6 Hz,
1H), 5.04 (dd, J ¼ 2.4, 8.0 Hz, 1H), 3.70 (t, J ¼ 8.0 Hz, 1H), 2.15 (d,
J ¼ 2.4 Hz, 1H); 13C NMR (CDCl3, 100 MHz)
d 147.3, 139.4, 136.8,
literature [68]. anti-isomer: 1H NMR (CDCl3, 400 MHz)
d
7.41e7.10
133.1,132.0 (two peaks), 129.1,128.8,128.6,128.3,127.7,127.6,126.3,
118.9, 111.5, 77.1, 58.0.
(m, 12H), 6.92 (t, J ¼ 7.6 Hz, 1H), 6.84 (d, J ¼ 7.6 Hz, 1H), 6.60 (dd,
J ¼ 8.4, 16.0 Hz, 1H), 6.39 (d, J ¼ 16.0 Hz, 1H), 5.23 (t, J ¼ 6.0 Hz, 1H),
3.91 (t, J ¼ 6.0 Hz, 1H), 3.77 (s, 3H), 2.72 (J ¼ 6.0 Hz, 1H); 13C NMR
4.5.11. (E)-1-(4-Chlorophenyl)-2,4-diphenylbut-3-en-1-ol (55)
syn-55 and anti-55 were isolated as an inseparable mixture
(119.1 mg, 72%, colorless solid, Rf 0.42: EtOAc/hexane ¼ 3:7). The 1H
NMR spectrum of anti-55 was identical with that reported in the
(CDCl3, 100 MHz)
d 156.5, 142.0, 137.5, 132.5, 130.3, 129.6, 128.47,
128.4, 128.2, 128.0, 127.2, 126.7, 126.3, 120.6, 110.4, 74.5, 55.8, 55.3.
syn-isomer: 1H NMR (CDCl3, 400 MHz)
d
7.41e7.10 (m, 12H),
6.85 (t, J ¼ 7.6 Hz, 1H), 6.70 (d, J ¼ 7.6 Hz, 1H), 6.4 0 (dd, J ¼ 8.4,
16.0 Hz, 1H), 6.19 (d, J ¼ 16.0 Hz, 1H), 5.33 (dd, d, J ¼ 6.0, 8.4 Hz, 1H),
3.84 (t, J ¼ 8.4 Hz, 1H), 3.75 (s, 1H), 2.52 (d, J ¼ 6.0 Hz, 1H); 13C NMR
literature [68]. anti-isomer: 1H NMR (CDCl3, 400 MHz)
d 7.38e7.06
(m, 14H), 6.58 (dd, J ¼ 8.0, 16.0 Hz,1H), 6.52 (d, J ¼ 16.0 Hz,1H), 4.88
(d, J ¼ 8.0 Hz, 1H), 3.62 (t, J ¼ 8.0 Hz, 1H), 2.05 (s, 1H); 13C NMR
(CDCl3, 100 MHz)
d
156.3,141.1,137.5, 131.1,130.5,128.8,128.47 (two
(CDCl3, 100 MHz) d 140.5, 140.4, 136.8, 133.8 (two peaks), 133.1,
peaks), 128.3, 127.8, 127.0, 126.4, 126.1, 120.4, 110.3, 73.4, 57.0, 55.2.
128.9, 128.7, 128.4, 128.2, 128.1, 127.8, 126.9, 126.5, 77.3, 58.6.
syn-isomer: 1H NMR (CDCl3, 400 MHz)
d
7.38e7.06 (m, 14H),
4.5.8. (E)-1-(3,4-Methylenedioxyphenyl)-2,4-diphenylbut-3-en-1-
ol (52)
6.25 (dd, J ¼ 8.0, 16.0 Hz, 1H), 6.18 (d, J ¼ 16.0 Hz, 1H), 4.95 (d,
J ¼ 8.0 Hz, 1H), 3.71 (t, J ¼ 8.0 Hz, 1H), 2.03 (s, 1H); 13C NMR (CDCl3,
syn-52 and anti-52 were isolated as an inseparable mixture
(128.2 mg, 75%, yellow oil, Rf 0.30: EtOAc/hexane ¼ 3:7). The 1H
NMR spectrum of anti-52 was identical with that reported in the
100 MHz) d 140.4,140.0,137.0,133.5,132.7 (two peaks),129.0,128.8,
128.7, 128.6, 128.4, 127.5, 127.4, 126.3, 77.2, 57.8.
literature [68]. anti-isomer: 1H NMR (CDCl3, 400 MHz)
d
7.38e7.10
4.5.12. (E)-1-(3-Furyl)-2,4-diphenylbut-3-en-1-ol (57)
(m, 10H), 6.75 (d, J ¼ 2.0 Hz, 1H), 6.58 (dd, J ¼ 8.0, 16.0 Hz, 1H), 6.60
(d, J ¼ 8.0 Hz, 1H), 6.56 (dd, J ¼ 2.0, 8.0 Hz, 1H), 6.52 (d, J ¼ 16.0 Hz,
1H), 5.86 (dd, J ¼ 2.0, 4.8 Hz, 2H), 4.82 (d, J ¼ 8.0 Hz, 1H), 3.64 (t,
syn-57 and anti-57 were isolated as an inseparable mixture
(62.8 mg, 44%, yellow solid, Rf 0.38: EtOAc/hexane ¼ 3:7). The 1H
NMR spectrum of anti-57 was identical with that reported in the
J ¼ 8.0 Hz, 1H), 2.33 (s, 1H); 13C NMR (CDCl3, 100 MHz)
d
147.5,
literature [68]. anti-isomer: 1H NMR (CDCl3, 400 MHz)
d 7.39e7.17
146.8, 140.9, 137.0, 136.0, 133.5, 129.3, 128.6, 128.5, 128.4, 127.6,
126.7, 126.4, 120.4, 107.7, 107.1, 100.9, 58.5.
(m, 12H), 6.59 (dd, J ¼ 4.4, 16.4 Hz, 1H), 6.54 (d, J ¼ 16.4 Hz, 1H), 6.18
(s, 1H), 4.95 (dd, J ¼ 3.6, 7.6 Hz, 1H), 3.68 (quint, J ¼ 3.6 Hz, 1H), 2.19
syn-isomer: 1H NMR (CDCl3, 400 MHz)
d
7.38e7.10 (m, 10H),
(d, J ¼ 3.6 Hz, 1H); 13C NMR (CDCl3, 100 MHz)
d 142.9, 141.0, 139.9,
137.0, 133.6, 129.3, 128.71, 128.7, 128.5, 127.7, 127.0, 126.7, 126.5,
6.85 (br s, 1H), 6.74 (dd, J ¼ 2.0, 8.0 Hz, 1H), 6.72 (d, J ¼ 8.0 Hz, 1H),

12
Y. Horino et al. / Tetrahedron 76 (2020) 131493
109.0, 70.6, 57.5.
some reactions for reproducibility. This work was financially sup-
ported by JSPS KAKENHI Grant Number JP18K05101.
syn-isomer: 1H NMR (CDCl3, 400 MHz)
d
7.39e7.17 (m, 12H),
6.36 (dd, J ¼ 5.2, 16.0 Hz, 1H), 6.34 (s, 1H), 6.32 (dd, J ¼ 5.2, 16.0 Hz,
1H), 5.01 (dd, J ¼ 3.6, 8.0 Hz, 1H), 3.77 (quint, J ¼ 3.6 Hz, 1H), 1.88 (d,
Appendix A. Supplementary data
J ¼ 3.6 Hz, 1H); 13C NMR (CDCl3, 100 MHz)
d 143.2, 140.4, 140.1,
137.2, 132.7, 129.2, 128.9, 128.8, 128.6, 127.5, 127.3, 126.6, 126.3,
109.1, 70.4, 56.7.
Supplementary data to this article can be found online at
https://doi.org/10.1016/j.tet.2020.131493.
4.5.13. (E)-1,4,6-Triphenylhexa-1,5-dien-3-ol (58)
Supplementary Material
major isomer: 1H NMR (CDCl3, 400 MHz)
d 7.42e7.18 (m, 15H),
6.66 (d, J ¼ 16.0 Hz, 1H), 6.54e6.45 (m, 2H), 6.30 (dd, J ¼ 6.4,
Supplementary material that may be helpful in the review
process should be prepared and provided as a separate electronic
file. That file can then be transformed into PDF format and sub-
mitted along with the manuscript and graphic files to the appro-
priate editorial office.
16.0 Hz, 1H), 4.66 (t, J ¼ 6.4 Hz, 1H), 3.70 (dt, J ¼ 3.6, 6.4 Hz, 1H); 13
C
NMR (CDCl3, 100 MHz)
d 140.5, 137.2, 136.8, 132.9, 131.8, 129.9,
129.2, 129.0, 128.8, 128.7, 128.6, 127.8, 127.6, 127.2, 126.7, 126.4, 75.7,
56.6; HRMS (EI): found 308.1565. C24H20 (-H2O) requires 308.1580.
minor isomer: 1H NMR (CDCl3, 400 MHz)
d 7.42e7.18 (m, 15H),
6.63e6.55 (m, 3H), 6.15 (dd, J ¼ 6.4, 16.0 Hz, 1H), 4.61 (dt, J ¼ 1.2,
References
6.4 Hz, 1H), 3.64 (m, 1H); Characteristic peaks of 13C NMR (CDCl3,
100 MHz) d 140.9, 137.1, 136.9, 132.9, 131.4, 129.3, 128.8, 128.6, 127.8,
127.7, 127.1, 126.6, 126.5, 75.6, 56.9.
[1] S.E. Denmark, G.L. Beutner, Angew. Chem. Int. Ed. 47 (2008) 1560e1638.
[2] C. Chuit, R.J.P. Corriu, C. Reye, J.C. Young, Chem. Rev. 93 (1993) 1371e1448.
[3] L. Chabaud, P. James, Y. Landais, Eur. J. Org Chem. (2004) 3173e3199.
[4] T. Komiyama, Y. Minami, T. Hiyama, ACS Catal. 7 (2017) 631e651.
[5] Y. Hatanaka, T. Hiyama, J. Org. Chem. 53 (1988) 918e920.
[6] T. Hiyama, Y. Hatanaka, Pure Appl. Chem. 66 (1994) 1471e1478.
[7] T. Komiyama, Y. Minami, T. Hiyama, Synlett 28 (2017) 1873e1884.
[8] A. Hosomi, M. Endo, H. Sakurai, Chem. Lett. 5 (1976) 941e942.
[9] A. Hosomi, H. Sakurai, Tetrahedron Lett. 17 (1976) 1295e1298.
[10] A. Hosomi, H. Sakurai, J. Am. Chem. Soc. 99 (1977) 1673e1675.
[11] S.E. Denmark, J. Fu, Chem. Rev. 103 (2003) 2763e2794.
[12] M. Wadamoto, H. Yamamoto, J. Am. Chem. Soc. 127 (2005) 14556e14557.
[13] C.H. Larsen, B.H. Ridgway, J.T. Shaw, D.M. Smith, K.A. Woerpel, J. Am. Chem.
Soc. 127 (2005) 10879e10884.
[14] J.L. Hofstra, A.H. Cherney, C.M. Ordner, S.E. Reisman, J. Am. Chem. Soc. 140
(2018) 139e142.
[15] C. Luo, J.S. Bandar, J. Am. Chem. Soc. 141 (2019) 14120e14125.
[16] B.M. Trost, D.L. Van Vranken, Chem. Rev. 96 (1996) 395e422.
[17] J.D. Weaver, A. Recio, A.J. Grenning, J.A. Tunge, Chem. Rev. 111 (2011)
1846e1913.
4.5.14. (E)-1,3-Diphenyl-5-methylhex-1-en-4-ol (59)
The 1H NMR spectrum of anti-59 was identical with that re-
ported in the literature [68].
anti-isomer: 1H NMR (CDCl3, 400 MHz)
d 7.41e7.18 (m, 10H),
6.59e6.53 (m, 2H), 3.68 (dd, J ¼ 4.8, 7.2 Hz, 1H), 3.60e3.56 (m, 1H),
1.89 (m,1H),1.55 (br s,1H),1.06 (d, J ¼ 7.2 Hz, 3H), 0.99 (d, J ¼ 7.2 Hz,
3H); 13C NMR (CDCl3, 100 MHz)
d 142.3, 137.2, 132.8, 130.0, 128.9,
128.7, 128.1, 127.6, 126.8, 126.4, 79.2, 53.8, 30.1, 20.2, 16.2.
syn-isomer: 1H NMR (CDCl3, 400 MHz)
d
7.41e7.18 (m,10H), 6.47
(d, J ¼ 16.0 Hz, 1H), 6.39 (dd, J ¼ 8.0, 16.0 Hz, 1H), 3.80 (dd, J ¼ 3.6,
8.4 Hz, 1H), 3.60e3.56 (m, 1H), 1.67 (m, 1H), 1.55 (br s, 1H), 0.99 (d,
J ¼ 7.2 Hz, 3H), 0.95 (d, J ¼ 6.8 Hz, 3H); 13C NMR (CDCl3, 100 MHz)
d
141.6, 137.4, 131.2, 130.7, 129.0, 128.7, 127.5, 127.1, 126.3, 78.9, 54.2,
[18] A.S. Pilcher, H.L. Ammon, P. DeShong, J. Am. Chem. Soc. 117 (1995)
5166e5167.
30.4, 20.6, 15.1.
ꢀ
ꢀ
[19] E. Belanger, K. Cantin, O. Messe, M. Tremblay, J.F. Paquin, J. Am. Chem. Soc. 129
(2007) 1034e1035.
4.5.15. (E)-1-Phenyl-2,4-di(4-methoxyphenyl)but-3-en-1-ol (61)
syn-61 and anti-61 were isolated as an inseparable mixture
(1.038 g, 72%, colorless solid, Rf 0.42: EtOAc/hexane ¼ 3:7).
[20] A.S. Pilcher, P. DeShong, J. Org. Chem. 61 (1996) 6901e6905.
[21] M.-R. Brescia, P. DeShong, J. Org. Chem. 63 (1998) 3156e3157.
[22] C.J. Handy, Y.F. Lam, P. DeShong, J. Org. Chem. 65 (2000) 3542e3543.
[23] M.E. Hoke, M.-R. Brescia, S. Bogaczyk, P. DeShong, B.W. King, M.T. Crimmins,
J. Org. Chem. 67 (2002) 327e335.
[24] M.H. Katcher, A.G. Doyle, J. Am. Chem. Soc. 132 (2010) 17402e17404.
[25] Philip L. Fuchs, Handbook of Reagents for Organic Synthesis, Reagents for
Silicon-Mediated Organic Synthesis, 2011.
[26] Y. Horino, N. Homura, K. Inoue, S. Yoshikawa, Adv. Synth. Catal. 354 (2012)
828e834.
[27] Y. Horino, Y. Takahashi, K. Koketsu, H. Abe, K. Tsuge, Org. Lett. 16 (2014)
3184e3187.
anti-isomer: 1H NMR (CDCl3, 400 MHz)
d 7.32e7.10 (m, 8H),
7.03e6.99 (m,1H), 6.90e6.87 (m,1H), 6.84e6.82 (m,1H), 6.78e6.73
(m, 2H), 6.46 (d, J ¼ 16.0 Hz, 1H), 6.41 (dd, J ¼ 8.0, 16.0 Hz, 1H), 4.85
(d, J ¼ 8.0 Hz, 1H), 3.75 (s, 3H), 3.73 (s, 3H), 3.64 (t, J ¼ 8.0 Hz, 1H),
2.37 (s, 1H); 13C NMR (CDCl3, 100 MHz)
d 159.3, 158.3, 142.2, 133.2,
132.8, 130.0, 129.4, 128.1, 127.6, 127.5, 127.2, 126.9, 114.1, 113.9, 77.9,
57.6, 55.4, 55.3.
[28] J.D. Buynak, J.B. Strickland, G.W. Lamb, D. Khasnis, S. Modi, D. Williams,
H. Zhang, J. Org. Chem. 56 (1991) 7076e7083.
anti-61 was prepared according to the reported method [68].
1
The H and 13C NMR data are in good agreement with each other.
[29] K. Tatsumi, S. Tanabe, Y. Tsuji, T. Fujihara, Org. Lett. 21 (2019) 10130e10133.
[30] L.J. Cheng, N.P. Mankad, J. Am. Chem. Soc. 142 (2020) 80e84.
[31] B.M. Trost, Z.T. Ball, J. Am. Chem. Soc. 126 (2004) 13942e13944.
[32] B.M. Trost, A. Bertogg, Org. Lett. 11 (2009) 511e513.
[33] K. Okamoto, E. Tamura, K. Ohe, Angew. Chem. Int. Ed. 52 (2013)
10639e10643.
syn-isomer: 1H NMR (CDCl3, 400 MHz)
d 7.32e7.10 (m, 8H),
7.03e6.99 (m,1H), 6.90e6.87 (m,1H), 6.84e6.82 (m,1H), 6.78e6.73
(m, 2H), 6.12 (d, J ¼ 16.0 Hz, 1H), 6.09 (dd, J ¼ 4.0, 16.0 Hz, 1H), 4.91
(dd, J ¼ 1.2, 8.0 Hz, 1H), 3.80 (s, 3H), 3.71 (dd, J ¼ 4.0, 8.0 Hz, 1H),
2.04 (s, 1H); 13C NMR (CDCl3, 100 MHz)
d 159.1, 158.8, 142.2, 132.8,
ꢀ
[34] E. Fillion, R.J. Carson, V.E. Trepanier, J.M. Goll, A.A. Remorova, J. Am. Chem. Soc.
126 (2004) 15354e15355.
132.5, 131.6 (two peaks), 130.2, 128.2, 127.8, 127.42, 127.1, 114.3,
114.0, 78.0, 56.9, 55.4, 55.4 (two peaks).
ꢀ
ꢀ
[35] E. Fillion, V.E. Trepanier, J.J. Heikkinen, A.A. Remorova, R.J. Carson, J.M. Goll,
A. Seed, Organometallics 28 (2009) 3518e3531.
[36] T. Korenaga, A. Ko, K. Uotani, Y. Tanaka, T. Sakai, Angew. Chem. Int. Ed. 50
(2011) 10703e10707.
Declaration of competing interest
[37] T. Korenaga, R. Sasaki, K. Shimada, Dalton Trans. 44 (2015) 19642e19650.
ꢀ
[38] V. Corce, L.M. Chamoreau, E. Derat, J.P. Goddard, C. Ollivier, L. Fensterbank,
Angew. Chem. Int. Ed. 54 (2015) 11414e11418.
[39] We Thank an Anonymous Reviewer for Providing Insightful Comments and
Suggestions.
[40] Gaussian 16, Revision C. 01, M.J. Frisch, G.W. Trucks, H.B. Schlegel,
G.E. Scuseria, M.A. Robb, J.R. Cheeseman, G. Scalmani, V. Barone,
G.A. Petersson, H. Nakatsuji, X. Li, M. Caricato, A.V. Marenich, J. Bloino,
B.G. Janesko, R. Gomperts, B. Mennucci, H.P. Hratchian, J.V. Ortiz,
A.F. Izmaylov, J.L. Sonnenberg, D. Williams-Young, F. Ding, F. Lipparini,
F. Egidi, J. Goings, B. Peng, A. Petrone, T. Henderson, D. Ranasinghe,
The authors declare that they have no known competing
financial interests or personal relationships that could have
appeared to influence the work reported in this paper.
Acknowledgments
We thank Mr. Yuhei Hayashi (University of Toyama) for checking

Y. Horino et al. / Tetrahedron 76 (2020) 131493
13
V.G. Zakrzewski, J. Gao, N. Rega, G. Zheng, W. Liang, M. Hada, M. Ehara,
K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao,
H. Nakai, T. Vreven, K. Throssell, J.A. Montgomery Jr., J.E. Peralta, F. Ogliaro,
M.J. Bearpark, J.J. Heyd, E.N. Brothers, K.N. Kudin, V.N. Staroverov, T.A. Keith,
R. Kobayashi, J. Normand, K. Raghavachari, A.P. Rendell, J.C. Burant,
S.S. Iyengar, J. Tomasi, M. Cossi, J.M. Millam, M. Klene, C. Adamo, R. Cammi,
J.W. Ochterski, R.L. Martin, K. Morokuma, O. Farkas, J.B. Foresman, D.J. Fox,
Gaussian, Inc., Wallingford CT, 2019.
[53] X.-L. Tang, Z. Wu, M.-B. Li, Y. Gu, S.-K. Tian, Eur. J. Org Chem. (2012)
4107e4109.
~
[54] P.-A. Deyris, T. Caneque, Y. Wang, P. Retailleau, F. Bigi, R. Maggi, G. Maestri,
M. Malacria, ChemCatChem 7 (2015) 3266e3269.
[55] S.-R. Sheng, X. Huang, J. Chin. Chem. Soc. 50 (2003) 893e896.
[56] C. Chen, T.R. Dugan, W.W. Brennessel, D.J. Weix, P.L. Holland, J. Am. Chem. Soc.
136 (2014) 945e955.
ꢀ
[57] R. Riveiros, R. Tato, J. Perez Sestelo, L.A. Sarandeses, Eur. J. Org Chem. (2012)
[41] Since the IRC Calculation for the Transition-State of Oxidative Addition (TS34-
35) Did Not Proceed, the Transition-State Was Confirmed by the NEB Method
Using Reaction Plus Pro2 Software.
3018e3023.
[58] G. Li, L. Wu, G. Lv, H. Liu, Q. Fu, X. Zhang, Z. Tang, Chem. Commun. 50 (2014)
6246e6248.
[42] A. Hosomi, A. Shirahata, H. Sakurai, Chem. Lett. 7 (1978) 901e904.
[43] A. Hosomi, A. Shirahata, H. Sakurai, Tetrahedron Lett. 19 (1978) 3043e3046.
[44] T. Hayashi, Y. Matsumoto, T. Kiyoi, Y. Ito, S. Kohra, Y. Tominaga, A. Hosomi,
Tetrahedron Lett. 29 (1988) 5667e5670.
[59] J. Kuroda, K. Inamoto, K. Hiroya, T. Doi, Eur. J. Org Chem. (2009) 2251e2261.
[60] D. Heijnen, F. Tosi, C. Vila, M.C.A. Stuart, P.H. Elsinga, W. Szymanski,
B.L. Feringa, Angew. Chem. Int. Ed. 56 (2017).
[61] M. Tobisu, T. Takahira, T. Morioka, N. Chatani, J. Am. Chem. Soc. 138 (2016)
6711e6714.
[62] T. Satoh, N. Hanaki, N. Yamada, T. Asano, Tetrahedron 56 (2000) 6223e6234.
[63] F. Ding, R. William, F. Wang, X.W. Liu, Chem. Commun. 48 (2012) 8709e8711.
[64] F. Chen, Y. Chen, H. Cao, Q. Xu, L. Yu, J. Org. Chem. 83 (2018) 14158e14164.
[65] Y. Horino, A. Aimono, H. Abe, Org. Lett. 17 (2015) 2824e2827.
[66] E.S. Schmidtmann, M. Oestreich, Angew. Chem. Int. Ed. 48 (2009) 4634e4638.
[67] Y. Horino, M. Sugata, H. Abe, Adv. Synth. Catal. 358 (2016) 1023e1028.
[68] Y. Horino, M. Sugata, I. Mutsuura, K. Tomohara, H. Abe, Org. Lett. 19 (2017)
5968e5971.
[45] S. Hayashi, K. Hirano, H. Yorimitsu, K. Oshima, J. Am. Chem. Soc. 128 (2006)
2210e2211.
ꢀ
[46] J.F. Cívicos, D.A. Alonso, C. Najera, Adv. Synth. Catal. 353 (2011) 1683e1687.
[47] S. Zhang, Y. Wang, X. Feng, M. Bao, J. Am. Chem. Soc. 134 (2012) 5492e5495.
[48] Y. Tsuji, S. Kajita, S. Isobe, M. Funato, J. Org. Chem. 58 (1993) 3607e3608.
[49] K. Nakajima, X. Guo, Y. Nishibayashi, Chem. Asian J. 13 (2018) 3653e3657.
[50] G. Wang, Y. Gan, Y. Liu, Chin. J. Chem. 36 (2018) 916e920.
[51] M. Sai, Adv. Synth. Catal. 360 (2018) 3482e3487.
[52] B. Yang, Z.-X. Wang, J. Org. Chem. 82 (2017) 4542e4549.