Lewis base-catalyzed [2,3]-Wittig rearrangement of silyl enolates generated from α-allyloxy carbonyl compounds

Article abstract of DOI:10.1246/bcsj.79.1275

Lewis base-catalyzed [2,3]-Wittig rearrangement of silyl enolates generated from α-allyloxy carbonyl compounds is described. The [2,3]-Wittig rearrangement of silyl enolates generated from α-allyloxy ketones proceeded smoothly by using a Lewis base cataly

Full text of DOI:10.1246/bcsj.79.1275

Ó 2006 The Chemical Society of Japan
Bull. Chem. Soc. Jpn. Vol. 79, No. 8, 1275–1287 (2006) 1275
Lewis Base-Catalyzed [2,3]-Wittig Rearrangement of Silyl Enolates
Generated from ꢀ-Allyloxy Carbonyl Compounds
ꢀ
Yoshinori Sato, Hidehiko Fujisawa, and Teruaki Mukaiyama
Center for Basic Research, The Kitasato Institute, 6-15-5 Toshima, Kita-ku, Tokyo 114-0003
Kitasato Institute for Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641
Received February 15, 2006; E-mail: mukaiyam@abeam.ocn.ne.jp
Lewis base-catalyzed [2,3]-Wittig rearrangement of silyl enolates generated from ꢀ-allyloxy carbonyl compounds
is described. The [2,3]-Wittig rearrangement of silyl enolates generated from ꢀ-allyloxy ketones proceeded smoothly by
using a Lewis base catalyst, such as lithio or sodio 2-pyrrolidone, in DMF at room temperature without an accompany-
ing [3,3]-Claisen rearrangement. The nature of the catalyst determines the pathway to proceed either by [2,3]-Wittig or
[3,3]-Claisen rearrangement. In addition [2,3]-Wittig rearrangement of silyl enolates generated from ꢀ-allyloxy esters
was tried. It was found that ammonium carboxylates, such as 4-methoxybenzoate, effectively promoted the reaction
to afford the [2,3]-Wittig rearrangement product in good yield. This is the first example of the Lewis base-catalyzed
[2,3]-Wittig rearrangement of silyl enolates generated from ꢀ-allyloxy carbonyl compounds.
A sigmatropic rearrangement is one of the most useful and
important tools for the formation of new carbon–carbon bonds.
Metal enolates, generated from ꢀ-allyloxy carbonyl com-
pounds, were known to give rearrangement products via two
different sigmatropic pathways:1 [2,3]-Wittig and [3,3]-Claisen
rearrangements (Scheme 1). The reaction pathway is deter-
mined by the nature of the enolates, i.e. [2,3]-Wittig rearrange-
ment occurred when the metal enolates generated from esters,2
amides,3 or carboxylic acids4 were used. However, both sigma-
tropic rearrangements took place when the metal enolates were
generated from ketones.5 Although the rearrangement of silyl
enolates generated from ketones or esters, proceeded via ther-
mal [3,3]-Claisen rearrangement,2a,5b,6 Nakai et al. reported
that the [2,3]-Wittig rearrangement of trimethylsilyl (TMS)
enolates generated from ꢀ-allyloxy esters took place in the
presence of a catalytic amount of silyl triflate.7
found that both the nitrogen anions generated from amides, or
imides, and the oxygen anions generated from carboxylic
acids, or alcohols, were efficient catalysts for promoting aldol,8
Michael,9 and Mannich-type10 reactions. In order to demon-
strate further the usefulness of the above mentioned catalysts,
Lewis base-catalyzed intramolecular reaction of silyl enolates
was then considered.11 In this paper, we report a Lewis base-
catalyzed [2,3]-Wittig rearrangement of silyl enolates which
were generated from ꢀ-allyloxy carbonyl compounds.
Results and Discussion
Metal Amide-Catalyzed [2,3]-Wittig Rearrangement of
Silyl Enolates, Generated from ꢀ-Allyloxy Ketones.
A
Lewis base-catalyzed intramolecular reaction was tried by
using a TMS enolate, generated from 2-allyloxy-1-tetralone
1a, as a model (Scheme 2). The reaction proceeded smoothly
when 1a was treated with a catalytic amount of lithium diphen-
ylamide in DMF at room temperature and afforded the [2,3]-
Wittig rearrangement product 2a in 81% yield, as well as the
[3,3]-Claisen rearrangement product 3a in 10% yield. On the
other hand, the [3,3]-Claisen rearrangement product 3a was
In the course of our investigations on the nucleophilic acti-
vation of TMS enolates by using a Lewis base catalyst, it was
R
Y
O
O
OSiMe3
O
O
LiNPh2
(20 mol%)
OH
H+
OM
OM
[2,3]-Wittig
rearrangement
DMF, rt
R
Lewis base catalyzed
[2,3]-Wittig rearrangement
1a
2a: 81% (3a: 10%)
R
Y
O
Y
R
O
O
[3,3]-Claisen
rearrangement
OM
OSiMe3
O
OH
O
H+
reflux
Y
THF
M = metal, SiR3
Y = alkyl, O-alkyl, NR2, OH
Thermal [3,3]-Claisen
rearrangement
1a
3a: 80%
Scheme 1.
Scheme 2.
Published on the web August 7, 2006; doi:10.1246/bcsj.79.1275

1276 Bull. Chem. Soc. Jpn. Vol. 79, No. 8 (2006)
Lewis Base-Catalyzed Wittig Rearrangement
Table 2. Screening of the Solvent
Table 1. Screening of Lewis Base Catalyst
OSiMe3
Catalyst
O
O
2a
OSiMe3
O
H+
(20 mol%)
+
3a
NLi
Solv., Time, rt
H+
DMF, rt, 1 h
2a
1a
1a
Yielda)/%
Entry
Solvent
Cat./mol %
Time/h
Yielda)/%
Entry
Catalyst
2a
3a
1
2
3
4
5
6
DMF
DMSO
Pyridine
THF
MeCN
CH2Cl2
20
30
20
30
30
30
1
1
24
48
48
48
93
90
37
15
15
trace
1b)
2
3
4
none
LiNPh2
LiN(SiMe3)2
LiNi-Pr2
O
n.d.
81
83
76
93
92
90
80
10
n.d.
trace
n.d.
n.d.
n.d.
5
6
M = Li
M = Na
M = K
a) Isolated yield. 3a was not detected.
NM
7
O
Table 3. Lewis Base-Catalyzed [2,3]-Wittig Rearrangement
of Silyl Enolates 1b–1d
8
92
n.d.
NLi
O
O
OSiR1
3
9
10
11
91
81
36
n.d.
n.d.
13
R = Me
R = Ph
NHLi
R = CF3
O
O
NM
(20 mol%)
DMF, rt, 1 h
R
R2
X
12
13
14
15e)
16f)
17e)
18
Succinimide Lic)
Phthalimide Lid)
PhOLi
66
32
13
45
n.d.
n.d.
n.d.
12
23
1b−d
2b−d
+
H+
trace
trace
n.d.
n.d.
n.d.
3b−d
PhONBu4
AcOLi
AcONMe4
4-MeOC6H4CO2NBu4
1b: SiR1 SiMe3 R2 = OMe X = CH2
=
3
1c:
SiMe3
SiEt3
CN
H
CH2
O
:
1d
a) Isolated yield. b) Reaction was carried out in THF at 50 ꢁC
for 6.5 h and another 2 h under reflux conditions. c) Lithium
salt of succinimide. d) Lithium salt of phthalimide. e) Reac-
tion time: 0.5 h. f) Reaction time: 5 h.
Yielda)/%
Entry
Substrate
Catalyst
2b–2d
3b–3d
1
2
3
1b
1b
1b
noneb)
M ¼ Li
M ¼ Na
noneb)
M ¼ Li
M ¼ Na
n.d.
71
92
12
afforded selectively in high yield by the thermolysis of 1a in
THF. These results strongly suggest that the activation by
Lewis base, or thermolysis, of the silyl enolate controlled the
two rearrangements.
98
n.d.
4
5
6
1c
1c
1c
n.d.
64
73
16
91
n.d.
Then, the reaction conditions were optimized in order to
increase the amount of 2a, and Lewis base catalysts were
screened first (Table 1). It was found that the Lewis base cat-
alysts, such as lithium hexamethyldisilazide (LHMDS), lithio
2-pyrrolidone, and lithium acetoamide, were effective and
the [2,3]-Wittig rearrangement product 2a was afforded in
good yields without the corresponding [3,3]-Claisen rearrange-
ment product 3a (Entries 3–10). When lithium succinimide, or
lithium phthalimide, was used (Entries 12 and 13), on the other
hand, the [2,3]-Wittig rearrangement product 2a was obtained
in low to moderate yields along with a small amount of 3a.
Influence of the counter cation of the catalyst was next
examined by using sodio or potassio 2-pyrrolidone. The de-
sired product 2a was also produced selectively in good yields
(Entries 6 and 7).
7
8
9
1d
1d
1d
noneb)
M ¼ Li
M ¼ Na
n.d.
78
85
75
n.d.
n.d.
a) Isolated yield. b) Reaction was carried out in THF under
reflux conditions without catalyst.
ments took place when the carboxylates were used (Entries
14–18).
Next, the effects of solvents were examined in the presence
of lithio 2-pyrrolidone at room temperature (Table 2). It was
found that when DMF and DMSO were used, the rearrange-
ment product 2a was produced in high yields (Entries 1 and 2)
while other solvents, such as THF and MeCN, produced 2a
only in small amounts (Entries 3–6). In all cases, no [3,3]-
Claisen rearrangement product 3a was detected.
After optimizing the reaction conditions, Lewis base-cata-
lyzed [2,3]-Wittig rearrangement was studied by using silyl
enolates, prepared from 6-substituted 2-allyloxy-1-tetralones
1b and 1c and 3-allyloxy-4-chromanone 1d (Table 3). Lithio
2-pyrrolidone (20 mol %), which worked effectively for the
Additional Lewis base catalysts, such as the corresponding
phenoxide or carboxylates, were examined since they had
already been shown to be effective in aldol,8 Michael,9 and
Mannich-type10 reactions. However, the desired rearrange-
ment product 2a was obtained only in low yield when lithium
or tetrabutylammonium phenoxide was used, and no rearrange-

Y. Sato et al.
Bull. Chem. Soc. Jpn. Vol. 79, No. 8 (2006) 1277
Table 5. Effect of Silyl Group
OSiR1
Table 4. Effect of Allyloxy Part of Silyl Enolates
OSiMe3
O
R2
O
Catalyst
(20 mol%)
3
NLi
DMF, rt, 1 h
O
R1
H+
(20 mol%)
2a
O
1e, 1f
OH
DMF, rt, Time
H+
1
R1
R2
Entry
SiR1
Time/h
Yielda)/%
3
2e, 2f
LiN(SiMe3)2
1
2
3
4
5
1a
1g
1h
1i
SiMe3
SiEt3
Sii-Pr3
SiMe2t-Bu
SiMe2Ph
1
2
24
24
2
93
91b)
7
20
79
O
Catalyst:
4
NLi
5
Entry
R1
R2
Catalyst
Yielda)/%
1j
1
2
3
4
1e
1e
1f
1f
H
H
Me
Me
Me
Me
H
4
5
4
5
50b)
84c)
76c)
85b)
a) Isolated yield. b) Trace amount of 3a was detected.
Table 6. Steric Effect of Solvent
H
O
a) Isolated yield. b) 3 was not detected. c) Trace amount of 3
was detected.
OSiMe3
NLi
O
H+
(20 mol%)
2a
Solv., rt, 24 h
[2,3]-Wittig rearrangement of silyl enolate 1a, was employed,
and the reaction proceeded smoothly to afford the correspond-
ing [2,3]-Wittig rearrangement products 2b–2d in moderate
yields along with a small amounts of the [3,3]-Claisen rear-
rangement products 3b or 3c (Entries 2, 5, and 8). In order to
increase the selectivity, several other catalysts were screened.
The sodium cation was found to be the most effective counter
cation for 2-pyrrolidone and promoted the reaction to afford
the [2,3]-Wittig rearrangement product selectively (Entries 3,
6, and 9).
1a
Entry
1
Solvent
Yielda)/%
37
N
Pyridine
Me
N
2
3
4-Picoline
56
4
Me
N
2-Picoline
Me
N
On the other hand, when thermolysis of 1b–1d was tried in
refluxing THF, the corresponding [3,3]-Claisen rearrangement
products 3b–3d were afforded selectively (Entries 1, 4, and 7).
These results indicate that the above two rearrangements are
controlled by the reaction conditions, i.e., either Lewis base
activation or thermolysis of the silyl enolate.
4
5
2,4-Lutidine
9
Me
Me
N
2,6-Lutidine
n.d.
The effect of the allyloxy group of the TMS enolate on this
rearrangement was further examined by using 1e and 1f
(Table 4). When the reactions were carried out in the presence
of lithio 2-pyrrolidone (4), the corresponding [2,3]-Wittig rear-
rangement products 2e and 2f were obtained in moderate
yields (Entries 1 and 3). The Lewis base catalysts were further
examined in order to improve the yields, and LHMDS (5) was
found to be the best catalyst for these enolates. The desired
[2,3]-Wittig rearrangement products were afforded in better
yields when LHMDS was used than when lithio 2-pyrrolidone
was used (Entries 2 and 4). The rearrangement product 2f was
obtained as an E-isomer, which was determined based on the
Me
a) Isolated yield. 3a was not detected.
ed in good yield (Entry 5). This result indicated that the elec-
trophilicity of the silyl group also influenced the reaction.
Therefore, the reaction was thought to proceed via the activa-
tion of silyl enolates by coordinating the Lewis base catalyst to
the silicon atom of the enolate, which is similar to other Lewis
base-catalyzed reactions.8–10
As mentioned above, a highly nucleophilic solvent, such as
DMF or DMSO, was needed in order to complete the reaction.
To examine the effect of solvents, the [2,3]-Wittig rearrange-
ment was performed in substituted pyridines by using TMS
enolate 1a in the presence of a catalytic amount of lithio 2-
pyrrolidone (Table 6). The reaction proceeded smoothly in
4-picoline, and 2a was afforded in better yield than in pyridine
(Entries 1 and 2). However, only a small amount of the rear-
rangement product was detected when 2-substituted pyridines,
such as 2-picoline, 2,4-lutidine, or 2,6-lutidine, were used
(Entries 3–5). This also indicated that the reactivity would
decrease remarkably if bulky substituents existed around the
1
previously reported H and 13C NMR data.12
Catalytic Cycle of Lewis Base-Catalyzed [2,3]-Wittig
Rearrangement. In order to understand the mechanism for
this reaction, the following experiments were tried. First, the
steric effect of the silyl group on this reaction was examined
by using 20 mol % of lithio 2-pyrrolidone (4) (Table 5). The
bulkiness of the silyl group of the enolate was found to strong-
ly influence the reactivity of this rearrangement (Entries 1–4).
However, in the case of dimethylphenylsilyl derivative 1j,
which has a bulky, electrophilic phenyl group, 2a was afford-

1278 Bull. Chem. Soc. Jpn. Vol. 79, No. 8 (2006)
Lewis Base-Catalyzed Wittig Rearrangement
O
OSiMe3
O
OSiMe3
M−LB
-
LB
M+
O
Si
OM
O
O
+ Me3Si−LB
LB
Si
-
M+
Solv
Solvent
O
O
Scheme 3. Proposed catalytic cycle for Lewis base-catalyzed [2,3]-Wittig rearrangement of silyl enolates generated from ꢀ-allyloxy
ketones.
nitrogen atom of the solvent. Thus, it was suggested that a sol-
O
X
O
X
vent molecule coordinated to the silicon atom of the enolate.
Based on these results, a catalytic cycle for this reaction was
proposed (Scheme 3). Namely, the initial coordination of a
Lewis base to the silicon atom of the enolate worked to form
a pentacoordinated hypervalent silicate, and further coordina-
tion of the solvent to the silicate afforded a hexacoordinated
hypervalent silicate. Thus, the reactivity of the enolate increas-
ed sufficiently enough to undergo [2,3]-Wittig rearrangement,
even at room temperature. Subsequent silylation of alkoxide
by the silylated Lewis base afforded O-silyl ether together with
the regeneration of the Lewis base to complete the catalytic
cycle.
Preparation of Silyl Enolates Generated from 2-Allyl-
oxy-1-tetralones or 3-Allyloxy-4-chromanone. ꢀ-Allyloxy
ketones 8a–8d were prepared from the corresponding carbonyl
compounds 6a–6d via ꢀ-diazo ketones 7a–7d (Scheme 4),
which were prepared by the formylation13 and deformylative
diazo transfer reactions14 of carbonyl compounds. The ꢀ-diazo
ketones were then treated with allyl alcohol in the presence
of a catalytic amount of diethyl ether–boron trifluoride (1/1)
N2
a, b
c
R1
R1
6a−d
7a−d
1, 6−8a: R1 = H, X = CH2
1, 6−8b: R1 = OMe, X = CH2
1, 6−8c: R1 = CN, X = CH2
1, 6−8d: R1 = H, X = O
O
OSiR2
3
O
O
d
R1
X
8a−d
R1
X
1a−d
1a, b, c: SiR23 = SiMe3
1d: SiR23 = SiEt3
Scheme 4. Reagents and conditions: a) MeONa, HCO2Et,
Benzene, rt; b) Et2NH, TsN3, Et2O, rt; c) Et2O BF3,
ꢂ
Allyl-OH, ꢃ20 ꢁC; d) LDA or LHMDS, TMSCl (1d:
TESCl), THF, ꢃ78 ꢁC.
(Et2O BF3) to obtain the desired ꢀ-allyloxy ketones 8a–8d
rangement of TNS enolate took place spontaneously at room
temperature, triethylsilyl (TES) enolate 1d was used because
it can be isolated by using column chromatography at room
temperature.
Ammonium Carboxylate-Catalyzed [2,3]-Wittig Rear-
rangement of Silyl Enolates Generated from ꢀ-Allyloxy
Esters. In order to increase the synthetic utility of this Lewis
base-catalyzed [2,3]-Wittig rearrangement, a reaction using
silyl enolates, generated from ꢀ-allyloxy esters, was tried
ꢂ
by eliminating the diazo group.15 Silyl enolates 1a–1d were
synthesized from the ꢀ-allyloxy ketones 8a–8d by successive
treatments with lithium diisopropylamide (LDA), or LHMDS,
and with chlorotrimethylsilane (TMSCl), or chlorotriethyl-
silane (TESCl), in THF at ꢃ78 ꢁC. After purification of the
crude silyl enolates by column chromatography (neutral silica
gel), they were used in the Lewis base-catalyzed [2,3]-Wittig
rearrangement reactions. Since the thermal [3,3]-Claisen rear-

Y. Sato et al.
Bull. Chem. Soc. Jpn. Vol. 79, No. 8 (2006) 1279
Table 8. Tetrabutylammonium Carboxylate-Catalyzed [2,3]-
Wittig Rearrangement of ꢀ-Allyloxy Ketene Silyl
Acetals
OSiMe3
OBn
Catalyst
(20 mol%)
H+
O
DMF, rt, 3 h
9a
Catalyst
(20 mol%)
OSiMe3
OR
OH
H+
O
CO2Bn
DMF, rt, 3 h
10a
9a−g
OH
O
CO2R
10a−g
LHMDS, 31%
Catalyst: AcONBu4 (11),
4-MeOC6H4CO2NBu4 (12)
Catalyst:
NLi, 38%
Scheme 5.
Li succinimide, 40%
Entry
R
Cat.
Yielda)/%
1
2
PhCH2
PhCH2
9a
9a
11
12
70
83
Table 7. Screening of Lewis Base Catalyst
3
4
4-MeOC6H4CH2
4-MeOC6H4CH2
9b
9b
11
12
82
77
Catalyst
OSiMe3
H+
(20 mol%)
O
OBn
DMF, rt, 3 h
5
6
4-ClC6H4CH2
4-ClC6H4CH2
9c
9c
11
12
63
84
9a
OH
CO2Bn
10a
7
8
4-CF3C6H4CH2
4-CF3C6H4CH2
9d
9d
11
12
40
49
Entry
Catalyst
Yielda)/%
9
10
Ph
Ph
9e
9e
11
12
n.d.
n.d.
1
2
PhOLi
PhONBu4
32
24
11
12
PhCH2CH2
PhCH2CH2
9f
9f
11
12
64
70
3
4
5
6
AcOLi
34
38
48
70
AcONa
AcOK
AcONBu4
13
14
Et
Et
9g
9g
11
12
75
73
a) Isolated yield.
7
8
t-BuCO2NBu4
PhCO2NBu4
71
49
however, the yield decreased when PhCO2NBu4 was used
(Entries 7 and 8). The effect of the substituent on the phenyl
group of PhCO2NBu4 was also examined, and the yields
became lower when tetrabutylammonium chlorobenzoate, or
nitrobenzoate, which has an electron-withdrawing group, was
used. On the other hand, better yields were obtained when an
electron-donating group was on the phenyl ring (Entries 9–15),
and tetrabutylammonium 4-methoxybenzoate was shown to be
the best catalyst for this reaction (Entry 11). It is interesting to
note that the desired product 10a was afforded in lower yield
when benzoates having a stronger electron-donating group,
such as dimethoxy, trimethoxy, or dimethylamino group than
the methoxy group were used (Entries 12–15). Formation of
[3,3]-Claisen rearrangement product was not observed in any
cases.
Next, the ammonium carboxylate-catalyzed [2,3]-Wittig re-
arrangement was tried by using various TMS enolates, 9a–9g,
in the presence of AcONBu4 (11) or tetrabutylammonium 4-
methoxybenzoate (12), in DMF at room temperature (Table 8).
Both TMS enolates 9b and 9c, having either an electron-donat-
ing or -withdrawing substituent in a phenyl group of the ester
moiety, respectively, afforded the [2,3]-Wittig rearrangement
products in good yields (Entries 3–6). However, enolate 9d,
which has a strong electron-withdrawing substituent, such as
trifluoromethyl group, afforded the desired product 10d in
moderate yields (Entries 7 and 8). When the TMS enolate
9f, or 9g, generated from alkyl ester were used, the corre-
sponding [2,3]-Wittig rearrangement product 10f or 10g were
also obtained in good yields (Entries 11–14). On the other
9
4-ClC6H4CO2NBu4
4-NO2C6H4CO2NBu4
4-MeOC6H4CO2NBu4
2-MeOC6H4CO2NBu4
2,4-(MeO)2C6H3CO2NBu4
3,4,5-(MeO)3C6H2CO2NBu4
4-Me2NC6H4CO2NBu4
30
trace
83
80
71
42
66
10
11
12
13
14
15
a) Isolated yield.
because their reactivity towards the rearrangement was known
to decrease compared to that of ꢀ-allyloxy ketones.2c,6c [2,3]-
Wittig rearrangement using silyl enolate 9a was carried out in
DMF in the presence of a catalytic amount of lithium amide at
room temperature (Scheme 5). The desired [2,3]-Wittig rear-
rangement product 10a was obtained in low yield; however,
similar reactions using silyl enolates generated from ketones
was promoted effectively.
Next, reactions using a Lewis base catalyst having an oxy-
gen anion generated from a phenol or carboxylic acid were
tried (Table 7). When lithium phenoxide, or lithium acetate,
was used, 10a was obtained in low yields (Entries 1 and 3).
In addition, the yield was influenced by the counter cation of
the acetates (Entries 3–5), and tetrabutylammonium acetate
(AcONBu4) behaved as a useful catalyst to afford 10a in
70% yield (Entry 6). Various ammonium carboxylates were
then screened in order to improve the efficiency of the reac-
tion. Tetrabutylammonium pivalate having a sterically hin-
dered t-butyl group showed the same reactivity to AcONBu4;

1280 Bull. Chem. Soc. Jpn. Vol. 79, No. 8 (2006)
Lewis Base-Catalyzed Wittig Rearrangement
Table 9. Effect of Allyloxy Group of Silyl Enolates
was shown that the effectiveness of the catalyst on this reaction
depended on the structures of silyl enolates, i.e., enolates gen-
erated from ketones were catalyzed by various metal amides
while only ammonium carboxylates were the effective cata-
lysts in the case of those generated from esters. The reaction
pathway, i.e., [2,3]-Wittig or [3,3]-Claisen rearrangement, was
controlled via Lewis base activation or thermolysis of silyl
enolate, respectively.
Catalyst
(20 mol%)
R2
OSiMe3
OBn
H+
R1
O
DMF, rt, 3 h
R1
R2 OH
9h−j
CO2Bn
R1 R1
Catalyst: AcONBu4 (11),
4-MeOC6H4CO2NBu4 (12)
10h−j
Experimental
Entry
Substrate
Cat.
Yielda)/%
General.
All melting points were determined using a
Yanagimoto micro melting point apparatus (Yanaco MP-S3) and
were not corrected. Infrared (IR) spectra were recorded using a
Bio-Rod FTS-165 or a Horiba FT-720 FT-IR spectrometer.
1H NMR spectra were recorded using a JEOL JNM-EX270L (270
MHz) spectrometer; chemical shifts (ꢁ) are reported in parts per
million relative to tetramethylsilane, except for the measurements
involving silyl enolates. Chemical shifts of the silyl enolates are
reported in parts per million relative to the solvent resonance as
the internal standard (C6D6, 7.20 ppm). Splitting patterns are des-
ignated as s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet;
br, broad. 13C NMR spectra were recorded using an EX270L
(68 MHz) spectrometer with complete proton decoupling. Chemi-
cal shifts are reported in parts per million relative to tetramethyl-
silane, with the solvent resonance as the internal standard (CDCl3,
77.0 ppm; C6D6, 128.0 ppm; DMSO-d6, 39.5 ppm). High resolu-
tion mass spectra (HRMS) were recorded on a JEOL AX505WA
(EI, CI) or a SX102A (EI, CI, FAB) mass spectrometer. High reso-
lution mass spectrometry analyses and several of the IR measure-
ments were carried out by Mitsui Chemical Analysis & Consulting
Service INC. Analytical TLC was performed using Merck prepar-
ative TLC plates (silica gel 60 GF254, 0.25 mm). Column chro-
matography was carried out using Merck silica gel 60 (0.063–
0.200 mm) unless otherwise noted. Preparative thin-layer chroma-
tography (PTLC) was carried out using silica gel Wakogel B-5F.
All reactions were carried out under an argon atmosphere in dried
glassware, unless otherwise noted. Anhydrous N,N-dimethylform-
amide (DMF) was purchased form Kanto Chemical and dried fur-
ther with calcium hydride; anhydrous tetrahydrofuran (THF) was
purchased form Kanto Chemical; dichloromethane was distilled
from diphosphorus pentaoxide, then from calcium hydride, and
finally dried over MS 4A; benzene was distilled from diphospho-
rus pentaoxide and dried over MS 4A; and diethyl ether was dried
over MS 4A. All reagents were purchased from Tokyo Kasei
Kogyo, Kanto Chemical, Wako Pure Chemical Industries,
Kokusan Chemical, or Aldrich Chemical, and were used without
further purification, unless otherwise noted.
1
2
3
11
12
11
12
11
12
23
40
16
Me
O
9h
9i
Me
O
4
5
6
17
77
80
Me
Cl
9j
O
a) Isolated yield.
a, b
OH
O
CO2R
BrCH2COOH
c
+
13
OSiMe3
OR
O
9
Scheme 6. Reagents and conditions: a) NaH, THF, reflux;
b) EDC HCl, DMAP, ROH, THF, 0 ꢁC; c) LHMDS,
TMSCl, THF, ꢃ78 ꢁC.
ꢂ
hand, the [2,3]-Wittig rearrangement product was not detected
when 9e was used (Entries 9 and 10).
Further, the effect of the allyloxy part of TMS enolates was
examined (Table 9). The rearrangement of the TMS enolate 9h
was tried, but the corresponding rearrangement product 10h
was obtained in low yield. The yield of the desired 10i was al-
so low when the TMS enolate 9i was used. Thus, the reactivity
was strongly influenced by the steric effect of the allyloxy sub-
stituent. Next, the TMS enolate 9j, which has a chlorine atom
on the allyloxy moiety was examined, and the reaction pro-
ceeded smoothly to afford the corresponding product 10j in
good yield. These results suggested a possibilities of more ef-
fective acceleration of this rearrangement involving the silyl
enolates having an electron-withdrawing substituent on the
allyloxy group.
Preparation of Silyl Enolates Generated from 3-Oxa-5-
hexenoate Esters. ꢀ-Allyloxy esters 13 were synthesized
by the esterification of carboxylic acid,16 which was prepared
from bromoacetic acid and allyl alcohol (Scheme 6).17 The
desired silyl enolates 9 were synthesized from 13 by reacting
with LHMDS, followed by successive reaction with chlorotri-
methylsilane (TMSCl) in THF at ꢃ78 ꢁC.
Preparation of the Lewis Bases. Lithium acetate was pur-
chased from Wako Pure Chemical Industries. Sodium and potas-
sium acetates were purchased from Kokusan Chemical. Tetra-
methylammonium acetate and potassium phthalimide were pur-
chased from Tokyo Kasei Kogyo. Lithium phenoxide solution
(1.0 M in THF) and tetrabutylammonium acetate were purchased
from Aldrich Chemical. Other Lewis base catalysts were prepared
by follwing the methods.
Metal Amides. Lithium amides were prepared from corre-
sponding precursors and MeLi (1.0 M in Et2O) in THF at 0 ꢁC
to give a 0.1 M solution of the lithium amides. Sodio and potassio
2-pyrrolidones were prepared from 2-pyrrolidone and sodium
hexamethyldisilazide (1.0 M in THF) or potassium hexamethyldi-
silazide (0.5 M in toluene) in THF at 0 ꢁC to give 0.1 M solution of
Conclusion
The Lewis base-catalyzed [2,3]-Wittig rearrangement of
silyl enolates, which were generated from ꢀ-allyloxy carbonyl
compounds in DMF at room temperature was established. It

Y. Sato et al.
Bull. Chem. Soc. Jpn. Vol. 79, No. 8 (2006) 1281
Lewis base. These Lewis base catalyst were used without further
purification.
General Procedure for the Preparation of ꢀ-Allyloxy
Ketones (8a–8f).15 To a solution of ꢀ-diazo ketone 7 (18.59
mmol) in allyl alcohol (40 mL) at ꢃ20 ꢁC (0 ꢁC in the case of
Tetrabutylammonium Phenoxide and Carboxylates.18 To a
MeOH solution of phenol or carboxylic acid was added tetrabutyl-
ammonium hydroxide in MeOH at room temperature. After stir-
ring for 30 min, the solvent was removed under reduced pressure
and the residue was azeotroped with toluene three times. Then, the
residue was dissolved in THF, or toluene, to give 0.1 M solution of
Lewis base. These Lewis base catalyst were used without further
purification.
7c) was added a solution of Et2O BF3 (0.930 mmol) in allyl alco-
ꢂ
hol (20 mL). After the reaction mixture was stirred for 3–5 h at
ꢃ20 ꢁC (room temperature in the case of 7c), the reaction was
quenched with saturated aqueous NaHCO3. The mixture was ex-
tracted with Et2O, and the combined organic layer was washed
with H2O and brine, then dried over MgSO4, and filtered. The
filtrate was concentrated under reduced pressure, and the crude
product was purified by column chromatography (silica gel, 20%
EtOAc–hexane) to afford the allyloxy ketone 8.
2-Allyloxy-1-tetralone (8a):12 Yield: 72%; Pale yellow oil;
IR (neat, cmꢃ1) 3071, 1692, 1647, 1601, 1101, 924; 1H NMR
(CDCl3) ꢁ 8.02 (dd, J ¼ 7:6, 1.4 Hz, 1H), 7.48 (td, J ¼ 7:6, 1.4
Hz, 1H), 7.31 (t, J ¼ 7:6 Hz, 1H), 7.24 (d, J ¼ 7:6 Hz, 1H), 5.96
(ddt, J ¼ 17:3, 10.3, 5.2 Hz, 1H), 5.33 (d, J ¼ 17:3 Hz, 1H), 5.21
(d, J ¼ 10:3 Hz, 1H), 4.43–4.36 (m, 1H), 4.21–4.08 (m, 2H),
3.20–2.99 (m, 2H), 2.41–2.18 (m, 2H); 13C NMR (CDCl3) ꢁ
196.6, 143.3, 134.4, 133.4, 131.7, 128.4, 127.4, 126.5, 117.3,
79.1, 71.3, 30.0, 27.4.
General Procedure for the Preparation of ꢀ-Diazo Ketones
(7a–7d).13,14 To a suspension of sodium methoxide (46.8 mmol)
in benzene (45 mL) was added ethyl formate (46.8 mmol). The
ice-cooled mixture was treated with a solution of the ketone 619
(23.4 mmol) in benzene (45 mL) and the temperature was allowed
to warm to room temperature. After the reaction mixture was stir-
red for 12 h, the reaction was quenched with ice-water and then
acidified with aqueous HCl (2.0 M). The mixture was extracted
with Et2O, and the combined organic layer was washed with
H2O and brine, and dried over Na2SO4. After filtration and evap-
oration of the solvent under reduced pressure, the formed ꢀ-for-
myl ketone was used in the next step without further purification.
To a solution of the above ꢀ-formyl ketone and p-toluenesul-
fonyl azide20 (25.7 mmol) in Et2O (50 mL) at 0 ꢁC was added di-
ethylamine (46.8 mmol) and then temperature was allowed to rise
to room temperature. The reaction mixture was stirred for 1–2 h
and then H2O was added. The mixture was extracted with Et2O,
and the combined organic layer was washed with H2O and brine,
and dried over Na2SO4. After filtration and evaporation of the
solvent under reduced pressure, the crude ꢀ-diazo ketone 7 was
purified by the method mentioned below.
2-Diazo-1-tetralone (7a):21 The crude compound was purified
by column chromatography (silica gel, 30% EtOAc–hexane) to
afford 7a (65%) as yellow solid. Mp 48–49 ꢁC (lit.21b 47–49 ꢁC);
IR (KBr, cmꢃ1) 2071, 1623, 1591, 1310; 1H NMR (CDCl3) ꢁ 8.01
(dd, J ¼ 7:6, 1.6 Hz, 1H), 7.44 (td, J ¼ 7:6, 1.6 Hz, 1H), 7.35
(t, J ¼ 7:6 Hz, 1H), 7.21 (d, J ¼ 7:6 Hz, 1H), 3.08–2.96 (m, 4H);
13C NMR (CDCl3) ꢁ 183.4, 139.9, 133.1, 132.3, 128.0, 126.9,
125.7, 62.7, 27.8, 20.8.
2-Diazo-6-methoxy-1-tetralone (7b):22 The crude compound
was purified by column chromatography (silica gel, 30% EtOAc–
hexane) to afford diazo ketone 7b (71%) as orange solid. Mp 68–
70 ꢁC (lit.22 75–76 ꢁC); IR (KBr, cmꢃ1) 2840, 2078, 1618, 1592,
1247; 1H NMR (CDCl3) ꢁ 7.95 (d, J ¼ 8:6 Hz, 1H), 6.84 (dd, J ¼
8:6, 2.5 Hz, 1H), 6.67 (d, J ¼ 2:5 Hz, 1H), 3.84 (s, 3H), 2.97–2.96
(m, 4H); 13C NMR (CDCl3) ꢁ 182.7, 162.7, 142.3, 128.0, 126.5,
112.9, 112.5, 61.8, 55.4, 28.2, 20.9.
2-Allyloxy-6-methoxy-1-tetralone (8b): The crude product
was purified by column chromatography (silica gel, EtOAc:
hexane:CH3Cl = 1:4:4). Yield: 72%; Blown oil; IR (neat, cmꢃ1
)
3080, 2841, 1686, 1601, 1252, 1098, 929; 1H NMR (CDCl3) ꢁ
7.99 (d, J ¼ 8:7 Hz, 1H), 6.82 (dd, J ¼ 8:7, 2.6 Hz, 1H), 6.67
(d, J ¼ 2:6 Hz, 1H), 5.96 (ddt, J ¼ 17:3, 10.4, 5.6 Hz, 1H), 5.31
(d, J ¼ 17:3 Hz, 1H), 5.19 (d, J ¼ 10:4 Hz, 1H), 4.42–4.34 (m,
1H), 4.22–4.13 (m, 1H), 4.04 (dd, J ¼ 10:2, 4.5 Hz, 1H), 3.83 (s,
3H), 3.15–2.90 (m, 2H), 2.38–2.13 (m, 2H); 13C NMR (CDCl3) ꢁ
195.2, 163.5, 145.8, 134.5, 129.8, 125.2, 117.1, 113.2, 112.2, 78.8,
71.2, 55.4, 30.0, 27.6; HRMS (CI) Found: m/z 233.1176, Calcd
for C14H17O3 ðM þ HÞþ: 233.1178.
2-Allyloxy-6-cyano-1-tetralone (8c):
Yield: 61%; Pale
yellow solid. Mp 55–59 ꢁC; IR (KBr, cmꢃ1) 3064, 2231, 1702,
1
1648, 1607, 1110, 930; H NMR (CDCl3) ꢁ 8.10 (d, J ¼ 7:6 Hz,
1H), 7.61–7.58 (m, 2H), 5.95 (ddt, J ¼ 17:3, 10.4, 5.4 Hz, 1H),
5.32 (d, J ¼ 17:3 Hz, 1H), 5.22 (d, J ¼ 10:4 Hz, 1H), 4.38–4.30
(m, 1H), 4.20–4.10 (m, 2H), 3.25–2.98 (m, 2H), 2.44–2.21 (m,
2H); 13C NMR (CDCl3) ꢁ 195.1, 143.8, 134.5, 133.9, 132.4,
129.8, 128.2, 117.8, 117.6, 116.5, 78.5, 71.3, 29.4, 26.7; HRMS
(CI) Found: m/z 228.1024, Calcd for C14H14NO2 ðM þ HÞþ:
228.1025.
3-Allyloxy-4-chromanone (8d):23 Yield: 61%; Pale yellow
oil; IR (neat, cmꢃ1) 3080, 1703, 1646, 1607, 1478, 1104, 1053,
934; 1H NMR (CDCl3) ꢁ 7.89 (dd, J ¼ 7:6, 1.6 Hz, 1H), 7.47 (td,
J ¼ 7:6, 1.6 Hz, 1H), 7.03 (t, J ¼ 7:6 Hz, 1H), 6.96 (d, J ¼ 7:6
Hz, 1H), 5.93 (ddt, J ¼ 17:3, 10.3, 5.4 Hz, 1H), 5.32 (d, J ¼
17:3 Hz, 1H), 5.23 (d, J ¼ 10:3 Hz, 1H), 4.53–4.34 (m, 3H),
4.23–4.11 (m, 2H); 13C NMR (CDCl3) ꢁ 190.7, 160.9, 135.9,
133.6, 127.3, 121.5, 119.7, 118.2, 117.6, 74.5, 71.9, 69.7.
2-(2-Methylallyloxy)-1-tetralone (8e): Yield: 51%; Yellow
oil; IR (neat, cmꢃ1) 3074, 2937, 1698, 1658, 1602, 1104, 901;
1H NMR (CDCl3) ꢁ 8.02 (dd, J ¼ 7:6, 1.4 Hz, 1H), 7.47 (td, J ¼
7:6, 1.4 Hz, 1H), 7.30 (t, J ¼ 7:6 Hz, 1H), 7.23 (d, J ¼ 7:6 Hz,
1H), 5.02–5.01 (m, 1H), 4.92–4.91 (m, 1H), 4.28 (d, J ¼ 12:7 Hz,
1H), 4.09 (d, J ¼ 12:7 Hz, 1H), 4.07 (dd, J ¼ 10:4, 4.7 Hz, 1H),
3.20–2.95 (m, 2H), 2.41–2.17 (m, 2H), 1.77 (s, 3H); 13C NMR
(CDCl3) ꢁ 196.6, 143.3, 141.9, 133.3, 131.8, 128.4, 127.4, 126.5,
112.3, 78.9, 74.1, 30.0, 27.3, 19.6; HRMS (CI) Found m/z:
217.1225, Calcd for C14H17O2 ðM þ HÞþ: 217.1229,
6-Cyano-2-diazo-1-tetralone (7c): The crude compound was
purified by recrystallization from EtOAc–hexane to afford the
diazo ketone 7c (81%) as blown solid. Mp 150–152 ꢁC; IR (KBr,
1
cmꢃ1) 2225, 2071, 1622, 1299; H NMR (CDCl3) ꢁ 8.09 (d, J ¼
8:0 Hz, 1H), 7.63 (d, J ¼ 8:0 Hz, 1H), 7.27 (s, 1H), 3.12–3.00 (m,
4H); 13C NMR (DMSO-d6) ꢁ 181.3, 141.6, 135.8, 132.3, 130.4,
125.6, 118.1, 114.3, 63.9, 26.5, 19.2.
3-Diazo-4-chromanone (7d):21a,23 The crude compound was
purified by column chromatography (silica gel, 20% EtOAc–
hexane) to afford the diazo ketone 7d (70%) as yellow solid. Mp
61–64 ꢁC (lit.23 52–55 ꢁC); IR (KBr, cmꢃ1) 2113, 1627, 1604,
1333; 1H NMR (CDCl3) ꢁ 7.91 (dd, J ¼ 7:7, 1.6 Hz, 1H), 7.43 (td,
J ¼ 7:7, 1.6 Hz, 1H), 7.09 (t, J ¼ 7:7 Hz, 1H), 6.96 (d, J ¼ 7:7
Hz, 1H), 5.20 (s, 2H); 13C NMR (CDCl3) ꢁ 178.3, 159.1, 134.6,
126.1, 122.3, 122.2, 117.5, 62.1, 58.7.
2-(1-Methylallyloxy)-1-tetralone (8f):
The crude product

1282 Bull. Chem. Soc. Jpn. Vol. 79, No. 8 (2006)
Lewis Base-Catalyzed Wittig Rearrangement
was obtained as diastereomeric mixture, and they were separated
by column chromatography (silica gel, 10% EtOAc–hexane).
Less-polar isomer: Yield: 19%; Yellow oil; IR (neat, cmꢃ1) 3074,
2979, 2931, 1698, 1641, 1602, 1101, 940; 1H NMR (CDCl3) ꢁ
8.01 (dd, J ¼ 7:6, 1.4 Hz, 1H), 7.46 (td, J ¼ 7:6, 1.4 Hz, 1H), 7.30
(t, J ¼ 7:6 Hz, 1H), 7.22 (d, J ¼ 7:6 Hz, 1H), 5.75 (ddd, J ¼ 17:3,
10.3, 7.4 Hz, 1H), 5.24–5.13 (m, 2H), 4.38–4.28 (m, 1H), 4.12 (dd,
J ¼ 10:9, 4.9 Hz, 1H), 3.16–2.96 (m, 2H), 2.30–2.16 (m, 2H),
1.35 (d, J ¼ 6:4 Hz, 3H); 13C NMR (CDCl3) ꢁ 197.6, 143.3,
139.7, 133.2, 131.9, 128.4, 127.3, 126.5, 116.4, 77.1, 76.9, 30.8,
27.7, 21.6; HRMS (CI) Found m/z: 217.1227, Calcd for C14H17O2
ðM þ HÞþ: 217.1229. More-polar isomer: Yield: 35%; Yellow oil;
IR (neat, cmꢃ1) 3074, 2977, 2931, 1699, 1643, 1603, 1101, 927;
1H NMR (CDCl3) ꢁ 8.03 (dd, J ¼ 7:6, 1.4 Hz, 1H), 7.47 (td, J ¼
7:6, 1.4 Hz, 1H), 7.30 (t, J ¼ 7:6 Hz, 1H), 7.23 (d, J ¼ 7:6 Hz,
1H), 5.89 (ddd, J ¼ 17:3, 10.5, 7.0 Hz, 1H), 5.23 (d, J ¼ 17:3 Hz,
1H), 5.12 (d, J ¼ 10:5 Hz, 1H), 4.25–4.15 (m, 2H), 3.18–2.90
(m, 2H), 2.42–2.11 (m, 2H), 1.34 (d, J ¼ 6:2 Hz, 3H); 13C NMR
(CDCl3) ꢁ 196.2, 143.1, 139.9, 133.2, 131.9, 128.3, 127.5, 126.5,
115.7, 77.5, 75.6, 29.7, 27.5, 21.0; HRMS (CI) Found m/z:
217.1233, Calcd for C14H17O2 ðM þ HÞþ: 217.1229.
845; 1H NMR (C6D6) ꢁ 7.33 (d, J ¼ 7:9 Hz, 1H), 7.09 (d, J ¼
7:9 Hz, 1H), 6.80 (s, 1H), 5.76 (ddt, J ¼ 17:0, 10.3, 5.1 Hz, 1H),
5.18 (d, J ¼ 17:0 Hz, 1H), 5.02 (d, J ¼ 10:3 Hz, 1H), 4.02 (d, J ¼
5:1 Hz, 2H), 2.24 (t, J ¼ 7:9 Hz, 2H), 1.97 (t, J ¼ 7:9 Hz, 2H),
0.28 (s, 9H); 13C NMR (C6D6) ꢁ 142.6, 139.5, 134.3, 133.7,
131.5, 130.7, 129.7, 121.2, 119.6, 117.2, 109.0, 69.0, 28.0, 23.9,
0.8; HRMS (CI) Found m/z: 300.1412, Calcd for C17H22NO2Si
ðM þ HÞþ: 300.1420.
3-Allyloxy-4-triethylsilyloxy-2H-chromene (1d): Chlorotri-
ethylsilane was used instead of the chlorotrimethylsilane in the
general procedure. Yield: 43%; Pale yellow oil; IR (neat, cmꢃ1
)
1
3078, 2954, 2875, 1676, 1479, 1240, 1099, 1043, 920; H NMR
(C6D6) ꢁ 7.66 (d, J ¼ 7:2 Hz, 1H), 7.04 (t, J ¼ 7:2 Hz, 1H), 7.01
(t, J ¼ 7:2 Hz, 1H), 6.97 (d, J ¼ 7:2 Hz, 1H), 5.82 (ddt, J ¼ 17:2,
10.4, 5.6 Hz, 1H), 5.21 (d, J ¼ 17:2 Hz, 1H), 5.04 (d, J ¼ 10:4 Hz,
1H), 4.71 (s, 2H), 4.09 (d, J ¼ 5:6 Hz, 2H), 1.13 (t, J ¼ 8:0 Hz,
9H), 0.89 (q, J ¼ 8:0 Hz, 6H); 13C NMR (C6D6) ꢁ 153.7, 134.3,
132.0, 131.1, 124.0, 122.1, 121.7, 119.4, 117.4, 115.6, 70.7, 66.2,
7.3, 6.9; HRMS (CI) Found m/z: 319.1724, Calcd for C18H27O3Si
ðM þ HÞþ: 319.1729.
2-(2-Methylallyloxy)-1-trimethylsilyloxy-3,4-dihydronaph-
thalene (1e): Yield: 60%; Pale yellow oil; IR (neat, cmꢃ1) 3070,
2954, 1655, 1250, 1092, 901, 845; 1H NMR (C6D6) ꢁ 7.66 (d, J ¼
7:6 Hz, 1H), 7.20 (t, J ¼ 7:6 Hz, 1H), 7.04 (t, J ¼ 7:6 Hz, 1H),
6.97 (d, J ¼ 7:6 Hz, 1H), 5.10–5.09 (m, 1H), 4.88–4.87 (m, 1H),
4.10 (s, 2H), 2.66 (t, J ¼ 8:0 Hz, 2H), 2.25 (t, J ¼ 8:0 Hz, 2H),
1.69 (s, 3H), 0.36 (s, 9H); 13C NMR (C6D6) ꢁ 142.4, 139.8,
135.4, 133.6, 133.0, 126.8, 126.7, 125.9, 121.6, 112.4, 72.3,
29.1, 24.9, 19.6, 0.9; HRMS (CI) Found m/z: 289.1624, Calcd
for C17H25O2Si ðM þ HÞþ: 289.1624.
General Procedure for the Preparation of the Silyl Enolates
Generated from ꢀ-Allyloxy Ketones (1a–1j). To a solution of
diisopropylamine (1.30 mmol) in THF (1.5 mL) was added butyl-
lithium (1.6 M in hexane, 1.20 mmol) at 0 ꢁC, and then the mixture
was cooled to ꢃ78 ꢁC. The reaction mixture was successively add-
ed a solution of allyloxy ketone 8 (1.00 mmol) in THF (1.5 mL)
and chlorotrimethylsilane (1.30 mmol) in THF (1.5 mL), and then,
the temperature was allowed to rise to room temperature. After
evaporation of the solvent, the residue was diluted with petroleum
ether and filtered through a short pad of celite. The filtrate was
concentrated under reduced pressure, and the crude product was
purified by column chromatography (silica gel; spherical and neu-
tral, 5% EtOAc–hexane) to afford the silyl enolate 1 as pale yel-
low oil.
2-Allyloxy-1-trimethylsilyloxy-3,4-dihydronaphthalene (1a):
Yield: 76%; Pale yellow oil; IR (neat, cmꢃ1) 3068, 2954, 1655,
1250, 1092, 930, 845; 1H NMR (C6D6) ꢁ 7.69 (d, J ¼ 7:6 Hz,
1H), 7.24–7.20 (m, 1H), 7.05 (t, J ¼ 7:6 Hz, 1H), 6.98 (d, J ¼
7:6 Hz, 1H), 5.87 (ddt, J ¼ 17:3, 10.5, 5.3 Hz, 1H), 5.25 (d, J ¼
17:3 Hz, 1H), 5.05 (d, J ¼ 10:5 Hz, 1H), 4.15 (d, J ¼ 5:4 Hz,
2H), 2.64 (t, J ¼ 8:1 Hz, 2H), 2.22 (t, J ¼ 8:1 Hz, 2H), 0.37
(s, 9H); 13C NMR (C6D6) ꢁ 139.4, 135.4, 135.0, 133.6, 133.2,
126.8, 126.8, 126.0, 121.6, 116.7, 69.4, 29.0, 25.0, 1.0; HRMS
(CI) Found m/z: 235.1454, Calcd for C16H23O2Si ðM þ HÞþ:
275.1467.
2-(1-Methylallyloxy)-1-trimethylsilyloxy-3,4-dihydronaph-
thalene (1f): Major diastereomer of 8f was used for starting ma-
terial. Hexamethyldisilazane was used instead of the diisopropyl-
amine in the general procedure. Yield: 41%; Colorless oil; IR
(neat, cmꢃ1) 3068, 2954, 1653, 1248, 1090, 914, 845; 1H NMR
(C6D6) ꢁ 7.62 (d, J ¼ 7:6 Hz, 1H), 7.20–6.98 (m, 3H), 5.84 (ddd,
J ¼ 17:0, 10.4, 6.4 Hz, 1H), 5.14 (d, J ¼ 17:0 Hz, 1H), 4.96 (d,
J ¼ 10:4 Hz, 1H), 4.50–4.45 (m, 1H), 2.68 (t, J ¼ 8:0 Hz, 2H),
2.25 (t, J ¼ 8:0 Hz, 2H), 1.28 (d, J ¼ 6:4 Hz, 3H), 0.35 (s, 9H):
13C NMR (C6D6) ꢁ 140.4, 138.7, 135.5, 133.8, 133.7, 126.8,
126.7, 125.9, 125.5, 121.6, 74.7, 29.2, 25.9, 21.5, 1.1; HRMS
(CI) Found m/z: 289.1617, Calcd for C17H25O2Si ðM þ HÞþ:
289.1624.
2-Allyloxy-1-triethylsilyloxy-3,4-dihydronaphthalene (1g):
Chlorotriethylsilane was used instead of the chlorotrimethylsilane
in the general procedure. Yield: 63%; Pale yellow oil; IR (neat,
cmꢃ1) 3070, 2954, 2875, 1655, 1238, 1091, 928; 1H NMR (C6D6)
ꢁ 7.76 (d, J ¼ 7:3 Hz, 1H), 7.23 (t, J ¼ 7:3 Hz, 1H), 7.06 (t, J ¼
7:3 Hz, 1H), 7.00 (d, J ¼ 7:3 Hz, 1H), 5.88 (ddt, J ¼ 17:3, 10.5,
5.4 Hz, 1H), 5.24 (d, J ¼ 17:3 Hz, 1H), 5.04 (d, J ¼ 10:5 Hz, 1H),
4.13 (d, J ¼ 5:4 Hz, 2H), 2.65 (t, J ¼ 8:0 Hz, 2H), 2.20 (t, J ¼
8:0 Hz, 2H), 1.13 (t, J ¼ 7:9 Hz, 9H), 0.87 (q, J ¼ 7:9 Hz, 6H);
13C NMR (C6D6) ꢁ 139.1, 135.4, 135.0, 133.6, 133.3, 126.8,
126.7, 126.0, 121.6, 116.7, 69.3, 29.1, 24.9, 7.4, 6.0; HRMS
(CI) Found m/z: 317.1927, Calcd for C19H29O2Si ðM þ HÞþ:
317.1937.
2-Allyloxy-6-methoxy-1-trimethylsilyloxy-3,4-dihydronaph-
thalene (1b): Hexamethyldisilazane was used instead of the di-
isopropylamine in the general procedure. Yield: 55%; Colorless
oil; IR (neat, cmꢃ1) 3080, 2954, 2833, 1658, 1250, 1105, 924,
1
845; H NMR (C6D6) ꢁ 7.61 (d, J ¼ 8:9 Hz, 1H), 6.77–6.73 (m,
2H), 5.92 (ddt, J ¼ 17:3, 10.4, 5.4 Hz, 1H), 5.28 (d, J ¼ 17:3 Hz,
1H), 5.06 (d, J ¼ 10:4 Hz, 1H), 4.18 (d, J ¼ 5:4 Hz, 2H), 3.41
(s, 3H), 2.63 (t, J ¼ 8:0 Hz, 2H), 2.26 (t, J ¼ 8:0 Hz, 2H), 0.40
(s, 9H); 13C NMR (C6D6) ꢁ 158.7, 137.3, 135.5, 135.2, 133.5,
128.2, 122.8, 116.6, 113.9, 111.1, 69.7, 54.9, 29.4, 25.2, 1.0;
HRMS (CI) Found m/z: 305.1564, Calcd for C17H25O3Si
ðM þ HÞþ: 305.1573.
2-Allyloxy-1-triisopropylsilyloxy-3,4-dihydronaphthalene
(1h): Triisopropylsilyl trifluoromethanesulfonate was used in-
stead of the chlorotrimethylsilane in the general procedure. Yield:
59%; Pale yellow oil; IR (neat, cmꢃ1) 3070, 2943, 2891, 1655,
1250, 1093, 920; 1H NMR (C6D6) ꢁ 7.78 (d, J ¼ 7:4 Hz, 1H), 7.20
(t, J ¼ 7:4 Hz, 1H), 7.00 (t, J ¼ 7:4 Hz, 1H), 6.94 (d, J ¼ 7:4 Hz,
2-Allyloxy-6-cyano-1-trimethylsilyloxy-3,4-dihydronaphtha-
lene (1c): Hexamethyldisilazane was used instead of the diiso-
propylamine in the general procedure. Yield: 89%; Pale yellow
oil; IR (neat, cmꢃ1) 3082, 2956, 2222, 1645, 1252, 1107, 926,

Y. Sato et al.
Bull. Chem. Soc. Jpn. Vol. 79, No. 8 (2006) 1283
1H), 5.81 (ddt, J ¼ 17:0, 10.4, 5.1 Hz, 1H), 5.14 (d, J ¼ 17:0 Hz,
1H), 4.97 (d, J ¼ 10:4 Hz, 1H), 4.00 (d, J ¼ 5:1 Hz, 2H), 2.59 (t,
J ¼ 8:0 Hz, 2H), 2.11 (t, J ¼ 8:0 Hz, 2H), 1.46–1.33 (m, 3H), 1.24
(d, J ¼ 7:0 Hz, 18H); 13C NMR (C6D6) ꢁ 138.5, 135.6, 135.0,
133.4, 133.2, 126.7, 126.7, 125.8, 121.7, 116.7, 68.8, 29.1, 24.4,
18.7, 14.3; HRMS (CI) Found m/z: 359.2405, Calcd for C22H35-
O2Si ðM þ HÞþ: 359.2406.
(s, 5H), 5.91 (ddt, J ¼ 16:8, 10.8, 5.8 Hz, 1H), 5.33–5.20 (m,
4H), 4.13–4.09 (m, 4H); 13C NMR (CDCl3) ꢁ 170.0, 135.2, 133.5,
128.4, 128.3, 128.3, 118.2, 72.4, 67.1, 66.5; HRMS (CI) Found m/
z: 207.1016, Calcd for C12H15O3 ðM þ HÞþ: 207.1021.
4-Methoxybenzyl 3-Oxa-5-hexenoate (13b): Yield: 86%; IR
(neat, cmꢃ1) 3080, 2839, 1753, 1647, 1614, 1516, 1250, 1195,
1131; 1H NMR (CDCl3) ꢁ 7.31 (d, J ¼ 6:8 Hz, 2H), 6.88 (d,
J ¼ 6:8 Hz, 2H), 5.90 (ddt, J ¼ 17:2, 10.3, 5.8 Hz, 1H), 5.29 (d,
J ¼ 17:2 Hz, 1H), 5.22 (d, J ¼ 10:3 Hz, 1H), 5.13 (s, 2H), 4.10–
4.07 (m, 4H), 3.81 (s, 3H); 13C NMR (CDCl3) ꢁ 170.1, 159.5,
133.5, 130.2, 127.3, 118.1, 113.8, 72.3, 67.1, 66.3, 55.2; HRMS
(EI) Found m/z: 236.1045, Calcd for C13H16O4 (M)þ: 236.1049.
4-Chlorobenzyl 3-Oxa-5-hexenoate (13c): Yield: 90%; IR
(neat, cmꢃ1) 3082, 1758, 1647, 1600, 1494, 1193, 1133, 1095;
1H NMR (CDCl3) ꢁ 7.36–7.28 (m, 4H), 5.91 (ddt, J ¼ 17:8, 11.0,
5.8 Hz, 1H), 5.34–5.21 (m, 2H), 5.16 (s, 2H), 4.13–4.08 (m, 4H);
13C NMR (CDCl3) ꢁ 169.9, 134.2, 133.7, 133.4, 129.7, 128.6,
118.2, 72.4, 67.0, 65.6; HRMS (CI) Found m/z: 241.0633, Calcd
for C12H14ClO3 ðM þ HÞþ: 241.0631.
2-Allyloxy-1-t-butyldimethylsilyloxy-3,4-dihydronaphthalene
(1i): t-Butyldimethylsilyl trifluoromethanesulfonate was used in-
stead of the chlorotrimethylsilane. Yield: 40%; Pale yellow oil; IR
(neat, cmꢃ1) 3070, 2954, 2931, 1655, 1250, 1090, 914, 841;
1H NMR (C6D6) ꢁ 7.78 (d, J ¼ 7:6 Hz, 1H), 7.24–7.20 (m, 1H),
7.04 (t, J ¼ 7:6 Hz, 1H), 6.98 (d, J ¼ 7:6 Hz, 1H), 5.86 (ddt, J ¼
17:0, 10.5, 5.4 Hz, 1H), 5.23 (d, J ¼ 17:0 Hz, 1H), 5.09 (d, J ¼
10:5 Hz, 1H), 4.11 (d, J ¼ 5:4 Hz, 2H), 2.63 (t, J ¼ 8:0 Hz, 2H),
2.19 (t, J ¼ 8:0 Hz, 2H), 1.17 (s, 9H), 0.34 (s, 6H); 13C NMR
(C6D6) ꢁ 139.4, 135.4, 135.0, 133.6, 132.9, 126.8, 126.6, 125.9,
121.8, 116.7, 69.2, 29.1, 26.5, 25.1, ꢃ3:7; HRMS (CI) Found
m/z 319.1938, Calcd for C19H29O2Si ðM þ HÞþ: 317.1937.
2-Allyloxy-1-dimethylphenylsilyloxy-3,4-dihydronaphthalene
(1j): Chlorodimethylphenylsilane was used instead of the chloro-
trimethylsilane in the general procedure. Yield: 50%; Pale yellow
oil; IR (neat, cmꢃ1) 3070, 2956, 1657, 1427, 1252, 1090, 918, 831;
1H NMR (C6D6) ꢁ 7.80–7.74 (m, 3H), 7.28–7.14 (m, 4H), 7.03 (td,
J ¼ 7:3, 1.5 Hz, 1H), 6.96 (d, J ¼ 7:3 Hz, 1H), 5.72 (ddt, J ¼ 17:0,
10.5, 5.4 Hz, 1H), 5.13 (d, J ¼ 17:0 Hz, 1H), 4.98 (d, J ¼ 10:5 Hz,
1H), 3.98 (d, J ¼ 5:4 Hz, 2H), 2.61 (t, J ¼ 8:0 Hz, 2H), 2.17 (t,
J ¼ 8:0 Hz, 2H), 0.62 (s, 6H); 13C NMR (C6D6) ꢁ 139.2, 138.8,
135.1, 134.9, 133.8, 133.5, 133.3, 129.7, 128.0, 126.8, 126.8,
126.0, 121.8, 116.7, 69.3, 29.0, 24.6, ꢃ0:2; HRMS (CI) Found
m/z: 337.1628, Calcd for C21H25O2Si ðM þ HÞþ: 337.1624.
General Procedure for the Preparation of the Alkyl 3-Oxa-
5-hexenoates 13a–13f and 13h–13j).16,17 To a suspension of NaH
(60% dispersion, 95.0 mmol) in THF (25 mL) at 0 ꢁC was added
a solution of allyl alcohol (40.0 mmol) in THF (15 mL), and then
the temperature was allowed to rise to room temperature. After stir-
red for 30 min at room temperature, the reaction mixture was cool-
ed to 0 ꢁC and added a solution of bromoacetic acid (36.0 mmol) in
THF (25 mL). The mixture was stirred for 30 min at room temper-
ature and refluxed for 1 h, and then, the reaction was quenched with
aqueous NaOH (1.0 M). The mixture was washed with AcOEt.
After the aqueous layer was acidified with aqueous HCl (2.0 M),
the reaction mixture was extracted with CH2Cl2. The combined
organic layer was washed with H2O and brine, then dried over
MgSO4, and filtered. The filtrate was concentrated under reduced
pressure to afford 3-oxa-5-hexenoic acid as a yellow oil, which
was used directly in the next step without further purification.
To a solution of above 3-oxa-5-hexenoic acid (10.3 mmol) in
CH2Cl2 (30 mL) were successively added 4-dimethylaminopyri-
dine (1.03 mmol), EDC [1-(3-dimethylaminopropyl)-3-ethylcar-
bodiimide] (11.4 mmol), and a solution of the corresponding alco-
hol (10.3 mmol) in CH2Cl2 (10 mL) at 0 ꢁC then the temperature
was allowed to rise to room temperature. After the reaction mix-
ture was stirred overnight, H2O was added. The mixture was ex-
tracted with CH2Cl2, and the combined organic layer was washed
with H2O and brine, then dried over Na2SO4, and filtered. The
filtrate was concentrated under reduced pressure, and the crude
product was purified by column chromatography (silica gel, 10%
EtOAc–hexane) to afford the alkyl 3-oxa-5-hexenoate 13 as color-
less oil.
4-Trifluoromethylbenzyl 3-Oxa-5-hexenoate (13d): Yield:
83%; IR (neat, cmꢃ1) 3084, 1761, 1648, 1623, 1327, 1191, 1128;
1H NMR (CDCl3) ꢁ 7.63 (d, J ¼ 8:1 Hz, 2H), 7.48 (d, J ¼ 8:1 Hz,
2H), 5.92 (ddt, J ¼ 17:3, 10.3, 5.8 Hz, 1H), 5.35–5.21 (m, 4H),
4.16–4.10 (m, 4H); 13C NMR (CDCl3) ꢁ 169.8, 139.2, 133.4,
130.2 (q, JCCF ¼ 32:3 Hz), 128.1, 125.3 (q, JCCCF ¼ 3:9 Hz),
123.8 (q, JCF ¼ 271:1 Hz), 118.1, 72.3, 66.9, 65.4; HRMS
(CI) Found m/z: 275.0895, Calcd for C13H14F3O3 ðM þ HÞþ:
275.0895.
Phenyl 3-Oxa-5-hexenoate (13e):
Yield: 55%; IR (neat,
cmꢃ1) 3078, 1774, 1647, 1593, 1493, 1195, 1123; 1H NMR
(CDCl3) ꢁ 7.39 (t, J ¼ 7:6 Hz, 2H), 7.24 (t, J ¼ 7:6 Hz, 1H), 7.11
(d, J ¼ 7:6 Hz, 2H), 5.97 (ddt, J ¼ 17:3, 10.3, 5.9 Hz, 1H), 5.36
(d, J ¼ 17:3 Hz, 1H), 5.28 (d, J ¼ 10:3 Hz, 1H), 4.35 (s, 2H),
4.19 (d, J ¼ 5:9 Hz, 2H); 13C NMR (CDCl3) ꢁ 168.8, 150.0,
133.5, 129.4, 126.0, 121.2, 118.5, 72.6, 67.1; HRMS (CI) Found
m/z: 193.0866, Calcd for C11H13O3 ðM þ HÞþ: 193.0867.
Phenylethyl 3-Oxa-5-hexenoate (13f): Yield: 81%; IR (neat,
cmꢃ1) 3086, 3030, 1755, 1648, 1604, 1195, 1134; 1H NMR
(CDCl3) ꢁ 7.34–7.20 (m, 5H), 5.90 (ddt, J ¼ 17:5, 10.4, 5.7 Hz,
1H), 5.28 (d, J ¼ 17:5 Hz, 1H), 4.72 (d, J ¼ 10:4 Hz, 1H), 4.38
(t, J ¼ 7:0 Hz, 2H), 4.07–4.04 (m, 4H), 2.97 (t, J ¼ 7:0 Hz, 2H);
13C NMR (CDCl3) ꢁ 170.1, 137.2, 133.5, 128.7, 128.3, 126.5,
118.0, 72.2, 67.0, 65.1, 35.0; HRMS (CI) Found m/z: 221.1177,
Calcd for C13H17O3 ðM þ HÞþ: 221.1178.
Benzyl 5-Methyl-3-oxa-5-hexenoate (13h): Yield: 58%; IR
(neat, cmꢃ1) 3069, 2945, 2914, 1758, 1657, 1193, 1133; 1H NMR
(CDCl3) ꢁ 7.37–7.34 (m, 5H), 5.19 (s, 2H), 4.97 (s, 1H), 4.93 (s,
1H), 4.09 (s, 2H), 4.00 (s, 2H), 1.74 (s, 3H); 13C NMR (CDCl3) ꢁ
170.0, 140.9, 135.2, 128.4, 128.2, 128.2, 113.2, 75.2, 66.8, 66.4,
19.4; HRMS (CI) Found m/z: 221.1178, Calcd for C13H17O3
ðM þ HÞþ: 221.1178.
Benzyl 6-Methyl-3-oxa-5-heptenoate (13i): Yield: 75%; IR
(neat, cmꢃ1) 3066, 2973, 2915, 1756, 1674, 1191, 1134; 1H NMR
(CDCl3) ꢁ 7.37–7.34 (m, 5H), 5.35 (t, J ¼ 7:2 Hz, 1H), 5.19 (s,
2H), 4.09–4.05 (m, 4H), 1.74 (s, 3H), 1.65 (s, 3H); 13C NMR
(CDCl3) ꢁ 170.2, 138.4, 135.2, 128.3, 128.2, 128.2, 119.8, 67.4,
66.7, 66.3, 25.8, 17.9; HRMS (FAB) Found m/z: 233.1183, Calcd
for C14H17O3 ðM ꢃ HÞþ: 233.1177.
Benzyl 5-Chloro-3-oxa-5-hexenoate (13j): Yield: 26%; IR
(neat, cmꢃ1) 3035, 1751, 1638, 1193, 1113, 898; 1H NMR
(CDCl3) ꢁ 7.36 (s, 5H), 5.48 (s, 1H), 5.40 (s, 1H), 5.20 (s, 2H),
4.18 (s, 4H); 13C NMR (CDCl3) ꢁ 169.5, 137.0, 135.1, 128.5,
Benzyl 3-Oxa-5-hexenoate (13a):
Yield: 98%; IR (neat,
cmꢃ1) 3068, 1757, 1648, 1195, 1133; 1H NMR (CDCl3) ꢁ 7.36

1284 Bull. Chem. Soc. Jpn. Vol. 79, No. 8 (2006)
Lewis Base-Catalyzed Wittig Rearrangement
128.4, 128.3, 114.3, 73.5, 67.1, 66.7; HRMS (CI) Found m/z:
241.0629, Calcd for C12H14ClO3 ðM þ HÞþ: 241.0631.
(d, J ¼ 8:1 Hz, 2H), 7.08 (d, J ¼ 8:1 Hz, 2H), 5.79 (ddt, J ¼ 17:3,
10.3, 5.4 Hz, 1H), 5.48 (s, 1H), 5.19 (d, J ¼ 17:3 Hz, 1H), 5.04 (d,
J ¼ 10:3 Hz, 1H), 4.51 (s, 2H), 3.91 (dt, J ¼ 5:4, 1.5 Hz, 2H),
0.31 (s, 9H); 13C NMR (C6D6) ꢁ 147.9, 141.5, 134.6, 129.7 (q,
JCCF ¼ 32:3 Hz), 127.9, 125.4 (q, JCCCF ¼ 3:9 Hz), 124.7 (q,
JCF ¼ 247:4 Hz), 116.9, 114.1, 73.3, 69.6, 0.7.
Preparation of Ethyl 3-Oxa-5-hexenoate (13g).24 To a sus-
pension of NaH (60% dispersion, 105.6 mmol) in DMF (70 mL) at
0 ꢁC was added ethyl glycolate (10.00 g, 96.1 mmol), and then the
temperature was allowed to rise to room temperature. After stir-
ring for 2 h at room temperature, the reaction mixture was cooled
to 0 ꢁC and allyl bromide (13.04 g, 107.8 mmol) was added. The
mixture was stirred for 2 h at room temperature and quenched with
saturated aqueous NH4Cl (1.0 M). The mixture was extracted with
Et2O, and the combined organic layer was washed with H2O and
brine, then dried over Na2SO4, and filtered. The filtrate was con-
centrated under reduced pressure, and the crude product was dis-
tilled to afford the ethyl 3-oxa-5-hexenoate (13g) (8.31 g, 60%) as
colorless oil. Bp 72–74 ꢁC (lit.24 70–74 ꢁC); IR (neat, cmꢃ1) 3084,
2985, 1756, 1648, 1205, 1136; 1H NMR (CDCl3) ꢁ 5.92 (ddt, J ¼
17:3, 10.3, 5.7 Hz, 1H), 5.31 (d, J ¼ 17:3 Hz, 1H), 5.24 (d, J ¼
10:3 Hz, 1H), 4.23 (q, J ¼ 7:1 Hz, 2H), 4.12–4.08 (m, 4H), 1.29
(t, J ¼ 7:1 Hz, 3H); 13C NMR (CDCl3) ꢁ 170.1, 133.5, 118.0,
72.2, 67.0, 60.8, 14.2; HRMS (CI) Found m/z: 145.0860, Calcd
for C7H13O3 ðM þ HÞþ: 145.0865.
1-Phenoxy-1-trimethylsilyloxy-3-oxa-1,5-hexadiene (9e):
Yield: 73%; IR (neat, cmꢃ1) 3079, 2960, 1716, 1646, 1254,
850; 1H NMR (C6D6) ꢁ 7.24–7.10 (m, 4H), 6.88 (t, J ¼ 7:3 Hz,
1H), 5.85–5.71 (m, 1H), 5.77 (s, 1H), 5.21 (dd, J ¼ 15:4, 3.7 Hz,
1H), 5.04 (dd, J ¼ 10:4, 3.2 Hz, 1H), 3.89 (dt, J ¼ 5:1, 1.5 Hz,
2H), 0.25 (s, 9H); 13C NMR (C6D6) ꢁ 157.6, 143.2, 134.4,
129.7, 122.6, 119.8, 117.1, 116.6, 73.1, 0.5.
1-(2-Phenylethoxy)-1-trimethylsilyloxy-3-oxa-1,5-hexadiene
(9f): Yield: 80%; IR (neat, cmꢃ1) 3086, 3028, 2956, 1755, 1709,
1643, 1604, 1252, 849; 1H NMR (C6D6) ꢁ 7.31–7.17 (m, 5H),
5.95 (ddt, J ¼ 17:5, 10.3, 5.4 Hz, 1H), 5.57 (s, 1H), 5.35 (d, J ¼
17:5 Hz, 1H), 5.16 (d, J ¼ 10:3 Hz, 1H), 4.07 (d, J ¼ 5:4 Hz, 2H),
3.89 (t, J ¼ 7:0 Hz, 2H), 2.90 (t, J ¼ 7:0 Hz, 2H), 0.41 (s, 9H);
13C NMR (C6D6) ꢁ 148.8, 138.6, 134.9, 129.2, 128.6, 126.6,
116.6, 112.9, 73.4, 69.3, 36.1, 0.7.
General Procedure for the Preparation of the Silyl Enolates
Generated from ꢀ-Allyloxy Esters (9a–9j). To a solution of
hexamethyldisilazane (2.46 mmol) in THF (1.5 mL) at 0 ꢁC was
added butyllithium (1.6 M in hexane, 2.27 mmol), and then mix-
ture was cooled to ꢃ78 ꢁC. The reaction mixture was successively
added a solution of allyloxy ester 13 (1.89 mmol) in THF (1.5 mL)
and chlorotrimethylsilane (2.46 mmol) in THF (1.5 mL), and then,
the temperature was allowed to rise to room temperature. After
evaporation of the solvent, the residue was diluted with petroleum
ether and filtered through a short pad of celite. The filtrate was
concentrated under reduced pressure to afford the silyl enolate
9 as pale yellow or colorless oil. The yield was determined by
1H NMR analysis using 1,3,5-trimethylbenzene as an internal
standard, and the purity of the enolate was calculated. The crude
silyl enolates were used without further purification.
1-Benzyloxy-1-trimethylsilyloxy-3-oxa-1,5-hexadiene (9a):
Yield: 85%; IR (neat, cmꢃ1) 3066, 2958, 1747, 1709, 1647,
1252, 849; 1H NMR (C6D6) ꢁ 7.30–7.11 (m, 5H), 5.82 (ddt,
J ¼ 17:3, 10.4, 5.4 Hz, 1H), 5.51 (s, 1H), 5.21 (d, J ¼ 17:3 Hz,
1H), 5.04 (d, J ¼ 10:4 Hz, 1H), 4.65 (s, 2H), 3.92 (td, J ¼ 5:4,
1.5 Hz, 2H), 0.32 (s, 9H); 13C NMR (C6D6) ꢁ 148.4, 137.5,
134.8, 128.5, 128.0, 127.9, 116.7, 113.8, 73.3, 70.6, 0.7.
1-Ethoxy-1-trimethylsilyloxy-3-oxa-1,5-hexadiene
(9g):
Yield: 72%; IR (neat, cmꢃ1) 3082, 2979, 1749, 1705, 1647, 1252,
849; 1H NMR (C6D6) ꢁ 5.86 (ddt, J ¼ 17:3, 10.3, 5.4 Hz, 1H),
5.48 (s, 1H), 5.26 (d, J ¼ 17:3 Hz, 1H), 5.06 (d, J ¼ 10:3 Hz, 1H),
3.98 (td, J ¼ 5:4, 1.5 Hz, 2H), 3.56 (q, J ¼ 7:0 Hz, 2H), 1.08 (t,
J ¼ 7:0 Hz, 3H), 0.34 (s, 9H); 13C NMR (C6D6) ꢁ 148.8, 135.0,
116.6, 112.7, 73.4, 64.0, 14.9, 0.7.
1-Benzyloxy-5-methyl-1-trimethylsilyloxy-3-oxa-1,5-hexa-
diene (9h): Yield: 76%; IR (neat, cmꢃ1) 3068, 2958, 1745, 1709,
1658, 1252, 849; 1H NMR (C6D6) ꢁ 7.29 (d, J ¼ 7:0 Hz, 2H),
7.20–7.11 (m, 3H), 5.53 (s, 1H), 5.04 (s, 1H), 4.87 (s, 1H), 4.66
(s, 2H), 3.88 (s, 2H), 1.66 (s, 3H), 0.33 (s, 9H); 13C NMR (C6D6)
ꢁ 148.2, 142.1, 137.5, 128.5, 128.1, 127.9, 113.8, 112.5, 76.3,
70.7, 19.6, 0.7.
1-Benzyloxy-6-methyl-1-trimethylsilyloxy-3-oxa-1,5-hepta-
diene (9i): Yield: 88%; IR (neat, cmꢃ1) 3089, 2960, 1745, 1709,
1678, 1252, 850; 1H NMR (C6D6) ꢁ 7.30 (d, J ¼ 6:8 Hz, 2H),
7.20–7.08 (m, 3H), 5.60 (s, 1H), 5.50–5.45 (m, 1H), 4.69 (s, 2H),
4.08 (d, J ¼ 6:8 Hz, 2H), 1.59 (s, 3H), 1.46 (s, 3H), 0.27 (s, 9H);
13C NMR (C6D6) ꢁ 148.2, 137.7, 136.2, 128.5, 128.0, 127.9,
121.7, 113.9, 70.7, 69.1, 25.8, 18.1, 0.8.
1-Benzyloxy-5-chloro-1-trimethylsilyloxy-3-oxa-1,5-hexa-
diene (9j): Yield: 65%; IR (neat, cmꢃ1) 3066, 2956, 1751, 1637,
1252, 874, 845; 1H NMR (C6D6) ꢁ 7.27–7.02 (m, 5H), 5.41 (s,
1H), 5.34 (dd, J ¼ 2:9, 1.4 Hz, 1H), 5.20 (dd, J ¼ 2:2, 1.1 Hz,
1H), 4.56 (s, 2H), 3.94 (dd, J ¼ 1:4, 1.1 Hz, 2H), 0.29 (s, 9H);
13C NMR (C6D6) ꢁ 149.3, 138.1, 137.2, 128.5, 128.1, 127.8,
113.3, 113.2, 74.6, 70.5, 0.6.
General Procedure of the Lewis Base-Catalyzed [2,3]-
Wittig Rearrangement. The solution of the Lewis base (0.1 M
in THF, 0.36 mL, 0.036 mmol) was evaporated under reduced
pressure and dissolved in DMF (0.5 mL). To the DMF solution
of Lewis base was added a solution of silyl enolate (0.18 mmol)
in DMF (1.5 mL) at room temperature. The reaction mixture
was stirred for an appropriate time at room temperature and
quenched with aqueous HCl (1.0 M). After stirring further for
30 min, the mixture was extracted with Et2O, and the combined
organic layer was washed with H2O and brine, then dried over
MgSO4, and filtered. The filtrate was concentrated under reduced
pressure, and the crude product was purified by preparative TLC
to give the corresponding [2,3]-Wittig rearrangement product.
1-(4-Methoxybenzyloxy)-1-trimethylsilyloxy-3-oxa-1,5-hexa-
diene (9b): Yield: 76%; IR (neat, cmꢃ1) 3078, 2956, 2837, 1749,
1
1707, 1614, 1516, 1252, 849; H NMR (C6D6) ꢁ 7.22 (d, J ¼ 8:6
Hz, 2H), 6.78 (d, J ¼ 8:6 Hz, 2H), 5.82 (ddt, J ¼ 17:0, 10.5,
5.4 Hz, 1H), 5.51 (s, 1H), 5.21 (d, J ¼ 17:0 Hz, 1H), 5.04 (d, J ¼
10:5 Hz, 1H), 4.63 (s, 2H), 3.93 (d, J ¼ 5:4 Hz, 2H), 3.31 (s, 3H),
0.33 (s, 9H); 13C NMR (C6D6) ꢁ 159.8, 148.3, 134.9, 129.9, 129.4,
116.6, 114.0, 113.8, 73.3, 70.4, 54.8, 0.8.
1-(4-Chlorobenzyloxy)-1-trimethylsilyloxy-3-oxa-1,5-hexa-
diene (9c): Yield: 54%; IR (neat, cmꢃ1) 3082, 2958, 1751, 1709,
1
1645, 1601, 1493, 1252, 849; H NMR (C6D6) ꢁ 7.11 (d, J ¼ 8:5
Hz, 2H), 6.97 (d, J ¼ 8:5 Hz, 2H), 5.80 (ddt, J ¼ 17:3, 10.3,
5.7 Hz, 1H), 5.46 (s, 1H), 5.20 (d, J ¼ 17:3 Hz, 1H), 5.04 (d, J ¼
10:3 Hz, 1H), 4.48 (s, 2H), 3.91 (d, J ¼ 5:7 Hz, 2H), 0.31 (s, 9H);
13C NMR (C6D6) ꢁ 147.9, 135.9, 134.7, 133.8, 129.4, 128.7,
116.8, 114.0, 73.3, 69.7, 0.7.
1-(4-Trifluoromethylbenzyloxy)-1-trimethylsilyloxy-3-oxa-
1,5-hexadiene (9d): Yield: 70%; IR (neat, cmꢃ1) 3081, 2960,
1751, 1709, 1647, 1622, 1327, 1254, 849; 1H NMR (C6D6) ꢁ 7.35

Y. Sato et al.
Bull. Chem. Soc. Jpn. Vol. 79, No. 8 (2006) 1285
2-Allyl-2-hydroxy-1-tetralone (2a):12 Colorless oil; IR (neat,
132.3, 128.6, 128.5, 128.4, 118.8, 69.9, 67.3, 38.6; HRMS (CI)
Found m/z: 207.1020, Calcd for C12H15O3 ðM þ HÞþ: 207.1021.
4-Methoxybenzyl 2-Hydroxy-4-pentenoate (10b): Colorless
oil; IR (neat, cmꢃ1) 3483, 3078, 2839, 1735, 1642, 1614, 1516,
1250, 1215; 1H NMR (CDCl3) ꢁ 7.30 (d, J ¼ 6:5 Hz, 2H), 6.89
(d, J ¼ 6:5 Hz, 2H), 5.83–5.68 (m, 1H), 5.14–5.06 (m, 4H), 4.33–
4.21 (m, 1H), 3.81 (s, 3H), 2.89 (d, J ¼ 5:9 Hz, 1H), 2.61–2.51
(m, 1H), 2.47–2.37 (m, 1H); 13C NMR (CDCl3) ꢁ 174.1, 159.6,
132.2, 130.2, 127.0, 118.7, 113.8, 69.9, 67.2, 55.3, 38.6; HRMS
(EI) Found m/z: 236.1045, Calcd for C13H16O4 (M)þ: 236.1049.
4-Chlorobenzyl 2-Hydroxy-4-pentenoate (10c): Colorless
oil; IR (neat, cmꢃ1) 3474, 3080, 1739, 1642, 1600, 1494, 1212,
1198, 1092; 1H NMR (CDCl3) ꢁ 7.37–7.24 (m, 4H), 5.84–5.68
(m, 1H), 5.22–5.06 (m, 4H), 4.33 (dt, J ¼ 5:9, 4.9 Hz, 1H), 2.78
(d, J ¼ 5:9 Hz, 1H), 2.63–2.53 (m, 1H), 2.49–2.39 (m, 1H);
13C NMR (CDCl3) ꢁ 174.0, 134.4, 133.4, 132.0, 129.8, 128.7,
118.9, 69.9, 66.5, 38.7; HRMS (CI) Found m/z: 241.0631, Calcd
for C12H14ClO3 ðM þ HÞþ: 241.0631.
1
cmꢃ1) 3488, 3075, 2933, 1685, 1640, 1604, 1092, 918; H NMR
(CDCl3) ꢁ 8.02 (dd, J ¼ 7:6, 1.4 Hz, 1H), 7.53 (td, J ¼ 7:6, 1.4
Hz, 1H), 7.35 (t, J ¼ 7:6 Hz, 1H), 7.27 (d, J ¼ 7:6 Hz, 1H), 5.88
(ddt, J ¼ 17:0, 10.3, 6.2 Hz, 1H), 5.17 (d, J ¼ 10:3 Hz, 1H), 5.09
(d, J ¼ 17:0 Hz, 1H), 3.82 (s, 1H), 3.18–2.94 (m, 2H), 2.49–2.32
(m, 3H), 2.23–2.11 (m, 1H); 13C NMR (CDCl3) ꢁ 201.0, 143.4,
134.1, 132.1, 130.1, 129.0, 128.0, 126.9, 119.1, 75.4, 40.3, 33.5,
26.1; HRMS (CI) Found m/z: 203.1072, Calcd for C13H15O2
ðM þ HÞþ: 203.1072.
2-Allyl-2-hydroxy-6-methoxy-1-tetralone (2b):
Colorless
oil; IR (neat, cmꢃ1) 3482, 3075, 2941, 2842, 1674, 1639, 1600,
1247, 1095, 918; 1H NMR (CDCl3) ꢁ 7.98 (d, J ¼ 8:6 Hz, 1H),
6.86 (d, J ¼ 8:6 Hz, 1H), 6.70 (s, 1H), 5.89 (ddt, J ¼ 18:1, 10.3,
8.1 Hz, 1H), 5.16 (d, J ¼ 10:3 Hz, 1H), 5.08 (d, J ¼ 18:1 Hz, 1H),
3.87 (s, 3H), 3.85 (s, 1H), 3.13–2.88 (m, 2H), 2.47–2.29 (m, 3H),
2.19–2.07 (m, 1H); 13C NMR (CDCl3) ꢁ 199.3, 164.0, 145.9,
132.2, 130.3, 123.4, 118.8, 113.7, 112.6, 75.0, 55.5, 40.6, 33.5,
26.6; HRMS (CI) Found m/z: 233.1175, Calcd for C14H17O3
ðM þ HÞþ: 233.1178.
4-Trifluoromethylbenzyl 2-Hydroxy-4-pentenoate (10d):
Colorless oil; IR (neat, cmꢃ1) 3474, 3082, 1743, 1643, 1623,
1
2-Allyl-6-cyano-2-hydroxy-1-tetralone (2c): Colorless oil;
IR (neat, cmꢃ1) 3497, 3080, 2937, 2234, 1685, 1643, 1608, 923;
1H NMR (CDCl3) ꢁ 8.11 (d, J ¼ 7:8 Hz, 1H), 7.64–7.61 (m, 2H),
5.85 (ddt, J ¼ 17:3, 10.3, 7.6 Hz, 1H), 5.20 (d, J ¼ 10:3 Hz, 1H),
5.10 (d, J ¼ 17:3 Hz, 1H), 3.67 (s, 1H), 3.20–3.00 (m, 2H), 2.48–
2.32 (m, 3H), 2.25–2.14 (m, 1H); 13C NMR (CDCl3) ꢁ 199.5,
143.8, 133.0, 132.9, 131.2, 130.1, 128.5, 119.7, 117.7, 117.1,
75.4, 40.1, 33.0, 25.9; HRMS (CI) Found m/z: 228.1023, Calcd
for C14H14NO2 ðM þ HÞþ: 228.1025.
1328, 1193, 1129; H NMR (CDCl3) ꢁ 7.64 (d, J ¼ 8:4 Hz, 2H),
7.48 (d, J ¼ 8:4 Hz, 2H), 5.85–5.70 (m, 1H), 5.27 (d, J ¼ 13:0
Hz, 1H), 5.25 (d, J ¼ 13:0 Hz, 1H), 5.15–5.08 (m, 2H), 4.35 (dt,
J ¼ 5:9, 4.9 Hz, 1H), 2.78 (d, J ¼ 5:9 Hz, 1H), 2.66–2.56 (m,
1H), 2.52–2.41 (m, 1H); 13C NMR (CDCl3) ꢁ 173.9, 138.9,
132.0, 130.6 (q, JCCF ¼ 32:4 Hz), 128.3, 125.5 (q, JCCCF ¼ 3:9
Hz), 123.8 (q, JCF ¼ 127:1 Hz), 119.0, 70.0, 66.3, 38.7; HRMS
(CI) Found m/z: 275.0895, Calcd for C13H14F3O3 ðM þ HÞþ:
275.0895.
3-Allyl-3-hydroxy-4-chromanone (2d):
Colorless oil; IR
Phenylethyl 2-Hydroxy-4-pentenoate (10f): Colorless oil;
IR (neat, cmꢃ1) 3475, 3080, 3030, 1737, 1642, 1605, 1213,
1197, 1136; 1H NMR (CDCl3) ꢁ 7.35–7.20 (m, 5H), 5.80–5.64 (m,
1H), 5.10–5.02 (m, 2H), 4.44–4.35 (m, 2H), 4.24 (dt, J ¼ 5:9,
4.9 Hz, 1H), 2.97 (t, J ¼ 6:9 Hz, 2H), 2.80 (d, J ¼ 5:9 Hz, 1H),
2.57–2.47 (m, 1H), 2.42–2.32 (m, 1H); 13C NMR (CDCl3) ꢁ
174.1, 137.1, 132.2, 128.7, 128.4, 126.6, 118.6, 69.9, 66.0, 38.6,
35.0; HRMS (CI) Found m/z: 221.1177, Calcd for C13H17O3
ðM þ HÞþ: 221.1178.
(neat, cmꢃ1) 3473, 3078, 2929, 1695, 1639, 1608, 1477, 1035,
924; 1H NMR (CDCl3) ꢁ 7.87 (dd, J ¼ 7:8, 1.6 Hz, 1H), 7.54
(td, J ¼ 7:8, 1.6 Hz, 1H), 7.07 (t, J ¼ 7:8 Hz, 1H), 7.00 (d, J ¼
7:8 Hz, 1H), 5.89–5.74 (m, 1H), 5.20 (d, J ¼ 10:3 Hz, 1H), 5.13
(d, J ¼ 17:0 Hz, 1H), 4.42 (d, J ¼ 11:2 Hz, 1H), 4.17 (d, J ¼
11:2 Hz, 1H), 3.62 (s, 1H), 2.50 (d, J ¼ 7:3 Hz, 2H); 13C NMR
(CDCl3) ꢁ 195.7, 161.2, 136.6, 130.7, 127.5, 121.8, 120.1, 118.2,
117.9, 72.6, 72.5, 39.2; HRMS (CI) Found m/z: 205.0862, Calcd
for C12H13O3 ðM þ HÞþ: 205.0865.
Ethyl 2-Hydroxy-4-pentenoate (10g):25 Colorless oil; IR
(neat, cmꢃ1) 3467, 3080, 2983, 1730, 1642, 1267, 1203; 1H NMR
(CDCl3) ꢁ 5.91–5.73 (m, 1H), 5.20–5.12 (m, 2H), 4.31–4.19 (m,
3H), 2.89 (d, J ¼ 5:9 Hz, 1H), 2.63–2.53 (m, 1H), 2.49–2.39 (m,
1H), 1.30 (t, J ¼ 7:3 Hz, 3H); 13C NMR (CDCl3) ꢁ 174.2, 132.3,
118.6, 69.9, 61.7, 38.7, 14.3; HRMS (CI) Found m/z: 145.0863,
Calcd for C7H13O3 ðM þ HÞþ: 145.0865.
2-Hydroxy-2-(2-methylallyl)-1-tetralone (2e): Colorless oil;
IR (neat, cmꢃ1) 3491, 3073, 2935, 1686, 1643, 1604, 1091, 895;
1H NMR (CDCl3) ꢁ 8.00 (dd, J ¼ 7:6, 1.4 Hz, 1H), 7.53 (td,
J ¼ 7:6, 1.4 Hz, 1H), 7.35 (t, J ¼ 7:6 Hz, 1H), 7.26 (d, J ¼ 7:6
Hz, 1H), 4.93–4.92 (m, 1H), 4.70 (brm, 1H), 3.88 (s, 1H), 3.23–
2.95 (m, 2H), 2.42–2.31 (m, 3H), 2.24–2.12 (m, 1H), 1.80 (brm,
3H); 13C NMR (CDCl3) ꢁ 201.1, 143.1, 140.8, 133.8, 130.2,
128.8, 127.8, 126.8, 115.3, 75.7, 43.6, 33.9, 26.5, 24.3; HRMS
(CI) Found m/z: 217.1225, Calcd for C14H17O2 ðM þ HÞþ:
217.1229.
Benzyl 2-Hydroxy-4-methyl-4-pentenoate (10h): Colorless
oil; IR (neat, cmꢃ1) 3484, 3072, 2920, 1739, 1650, 1264, 1195;
1H NMR (CDCl3) ꢁ 7.37 (s, 5H), 5.21 (s, 2H), 4.87 (brm, 1H),
4.79 (brm, 1H), 4.38 (ddd, J ¼ 8:1, 5.9, 4.1 Hz, 1H), 2.72 (d,
J ¼ 5:9 Hz, 1H), 2.55 (dd, J ¼ 14:0, 4.1 Hz, 1H), 2.37 (dd, J ¼
14:0, 8.1 Hz, 1H), 1.76 (s, 3H); 13C NMR (CDCl3) ꢁ 174.4,
140.6, 134.9, 128.5, 128.5, 128.3, 114.1, 69.1, 67.3, 42.6, 22.5;
HRMS (CI) Found m/z: 221.1176, Calcd for C13H17O3
ðM þ HÞþ: 221.1178.
2-(2-Butenyl)-2-hydroxy-1-tetralone (2f):12 Colorless oil; IR
1
(neat, cmꢃ1) 3491, 3066, 2935, 1687, 1604, 1093, 970; H NMR
(CDCl3) ꢁ 8.00 (dd, J ¼ 7:6, 1.3 Hz, 1H), 7.51 (td, J ¼ 7:6,
1.3 Hz, 1H), 7.33 (t, J ¼ 7:6 Hz, 1H), 7.25 (d, J ¼ 7:6 Hz, 1H),
5.58–5.41 (m, 2H), 3.76 (s, 1H), 3.16–2.91 (m, 2H), 2.41–2.25
(m, 3H), 2.20–2.09 (m, 1H), 1.68 (d, J ¼ 3:8 Hz, 3H); 13C NMR
(CDCl3) ꢁ 201.0, 143.3, 133.8, 130.1, 129.8, 128.9, 127.8,
126.7, 124.1, 75.5, 39.1, 33.5, 26.2, 18.1.
Benzyl 2-Hydroxy-3,3-dimethyl-4-pentenoate (10i): Color-
less oil; IR (neat, cmꢃ1) 3515, 2967, 1727, 1640, 1213, 1179;
1H NMR (CDCl3) ꢁ 7.36 (s, 5H), 5.82 (dd, J ¼ 17:3, 10.8 Hz,
1H), 5.23–4.97 (m, 4H), 3.92 (d, J ¼ 8:0 Hz, 1H), 2.76 (d, J ¼ 8:0
Hz, 1H), 1.07 (s, 6H); 13C NMR (CDCl3) ꢁ 173.4, 142.9, 134.9,
128.5, 128.5, 128.4, 113.5, 77.5, 67.2, 41.5, 23.6, 22.8; HRMS (CI)
Found m/z: 235.1335, Calcd for C14H19O3 ðM þ HÞþ: 235.1334.
Benzyl 4-Chloro-2-hydroxy-4-pentenoate (10j): Colorless
Benzyl 2-Hydroxy-4-pentenoate (10a):
Colorless oil; IR
(neat, cmꢃ1) 3476, 3078, 1738, 1642, 1214; H NMR (CDCl3) ꢁ
7.38–7.35 (m, 5H), 5.85–5.69 (m, 1H), 5.22–5.07 (m, 4H), 4.32
(td, J ¼ 6:3, 4.6 Hz, 1H), 2.77 (d, J ¼ 6:2 Hz, 1H), 2.65–2.54
(m, 1H), 2.50–2.39 (m, 1H); 13C NMR (CDCl3) ꢁ 174.2, 135.0,
1

1286 Bull. Chem. Soc. Jpn. Vol. 79, No. 8 (2006)
Lewis Base-Catalyzed Wittig Rearrangement
oil; IR (neat, cmꢃ1) 3466, 3035, 1735, 1637, 1268, 1198, 889;
1H NMR (CDCl3) ꢁ 7.37 (s, 5H), 5.30–5.23 (m, 4H), 4.52–4.49
(m, 1H), 2.91 (d, J ¼ 5:1 Hz, 1H), 2.85 (dd, J ¼ 14:8, 4.2 Hz,
1H), 2.68 (dd, J ¼ 14:8, 8.0 Hz, 1H); 13C NMR (CDCl3) ꢁ 173.6,
136.9, 134.7, 128.6, 128.6, 128.4, 116.0, 68.0, 67.8, 43.9; HRMS
(CI) Found m/z: 241.0626, Calcd for C12H14ClO3 ðM þ HÞþ:
241.0631.
References
a) F. E. Ziegler, Chem. Rev. 1988, 88, 1423. b) T. Nakai,
K. Mikami, Org. React. 1994, 46, 105.
a) S. Raucher, L. M. Gustavson, Tetrahedron Lett. 1986,
27, 1557. b) O. Takahashi, T. Saka, K. Mikami, T. Nakai, Chem.
Lett. 1986, 1355. c) O. Takahashi, T. Saka, K. Mikami, T.
Nakai, Chem. Lett. 1986, 1599. d) M. Uchikawa, T. Katsuki, M.
Yamaguchi, Tetrahedron Lett. 1986, 27, 4581.
1
2
General Procedure for the Thermal [3,3]-Claisen Rear-
rangement of the Silyl Enolates. The solution of silyl enolate
(0.179 mmol) in THF (3 mL) was refluxed for an appropriate time
and then aqueous HCl (1.0 M) was added. After stirring for another
30 min at room temperature, the mixture was extracted with Et2O,
and the combined organic layer was washed with H2O and brine,
then dried over MgSO4, and filtered. The filtrate was concentrated
under reduced pressure, and the crude product was purified by
preparative TLC to give the corresponding [3,3]-Claisen rear-
rangement product. Products and yields are as reported in the text.
1-Allyl-1-hydroxy-2-tetralone (3a):12 Pale yellow oil; IR
3
a) K. Mikami, O. Takahashi, T. Kasuga, T. Nakai, Chem.
Lett. 1985, 1729. b) M. Uchikawa, T. Hanamoto, T. Katsuki, M.
Yamaguchi, Tetrahedron Lett. 1986, 27, 4577.
4
T. Nakai, K. Mikami, S. Taya, Y. Kimura, T. Mimura,
Tetrahedron Lett. 1981, 22, 69.
a) A. F. Thomas, R. Dubini, Helv. Chim. Acta 1974, 57,
5
2084. b) M. Koreeda, J. I. Luengo, J. Am. Chem. Soc. 1985,
107, 5572.
6
a) J. L. C. Kachinski, R. G. Salomon, Tetrahedron Lett.
1
(neat, cmꢃ1) 3477, 3074, 2916, 1716, 1639, 1604, 920; H NMR
1977, 37, 3235. b) J. L. C. Kachinsky, R. G. Salomon, J. Org.
Chem. 1986, 51, 1393. c) O. Takahashi, T. Maeda, K. Mikami,
T. Nakai, Chem. Lett. 1986, 1355.
7 K. Mikami, O. Takahashi, T. Tabei, T. Nakai, Tetrahedron
Lett. 1986, 27, 4511.
(CDCl3) ꢁ 7.61 (d, J ¼ 7:6 Hz, 1H), 7.34–7.23 (m, 2H), 7.17 (d,
J ¼ 7:6 Hz, 1H), 5.80–5.68 (m, 1H), 5.12–5.03 (m, 2H), 4.03
(brs, 1H), 3.42–3.30 (m, 1H), 3.08 (ddd, J ¼ 16:5, 7.7, 4.1 Hz,
1H), 2.88 (ddd, J ¼ 18:1, 7.8, 4.1 Hz, 1H), 2.73–2.57 (m, 3H);
13C NMR (CDCl3) ꢁ 211.4, 139.5, 133.6, 131.7, 127.6, 127.6,
127.2, 125.8, 119.1, 78.8, 44.4, 33.6, 27.8.
8
a) H. Fujisawa, T. Mukaiyama, Chem. Lett. 2002, 182.
b) H. Fujisawa, T. Mukaiyama, Chem. Lett. 2002, 858. c) T.
Mukaiyama, H. Fujisawa, T. Nakagawa, Helv. Chim. Acta 2002,
85, 4518. d) T. Nakagawa, H. Fujisawa, T. Mukaiyama, Chem.
Lett. 2003, 32, 462. e) T. Nakagawa, H. Fujisawa, T. Mukaiyama,
Chem. Lett. 2003, 32, 696. f) T. Nakagawa, H. Fujisawa, T.
Mukaiyama, Chem. Lett. 2004, 33, 92. g) T. Nakagawa, H.
Fujisawa, Y. Nagata, T. Mukaiyama, Bull. Chem. Soc. Jpn.
2004, 77, 1555. h) H. Fujisawa, T. Nakagawa, T. Mukaiyama,
Adv. Synth. Catal. 2004, 346, 1241.
1-Allyl-1-hydroxy-6-methoxy-2-tetralone (3b): Pale yellow
oil; IR (neat, cmꢃ1) 3477, 3076, 2943, 2837, 1716, 1639, 1610,
1250, 915; 1H NMR (CDCl3) ꢁ 7.51 (d, J ¼ 8:6 Hz, 1H), 6.85
(dd, J ¼ 8:6, 2.4 Hz, 1H), 6.69 (d, J ¼ 2:4 Hz, 1H), 5.70 (ddt,
J ¼ 17:4, 10.0, 6.8 Hz, 1H), 5.11–5.01 (m, 2H), 3.97 (s, 1H), 3.80
(s, 3H), 3.37–3.25 (m, 1H), 3.02 (ddd, J ¼ 16:5, 7.6, 4.6 Hz, 1H),
2.86 (ddd, J ¼ 17:8, 7.8, 4.6 Hz, 1H), 2.71–2.54 (m, 3H);
13C NMR (CDCl3) ꢁ 211.3, 159.0, 135.0, 131.8, 131.7, 127.2,
118.9, 112.8, 112.8, 78.4, 55.3, 44.8, 33.8, 28.1; HRMS (CI)
Found m/z: 233.1179, Calcd for C14H17O3 ðM þ HÞþ: 233.1178.
1-Allyl-6-cyano-1-hydroxy-2-tetralone (3c): Pale yellow oil;
IR (neat, cmꢃ1) 3474, 3080, 2916, 2230, 1720, 1640, 1608, 924;
1H NMR (CDCl3) ꢁ 7.73 (d, J ¼ 8:1 Hz, 1H), 7.60 (d, J ¼ 8:1 Hz,
1H), 7.49 (s, 1H), 5.68 (ddt, J ¼ 17:0, 11.3, 7.0 Hz, 1H), 5.12 (d,
J ¼ 11:3 Hz, 1H), 5.06 (d, J ¼ 17:0 Hz, 1H), 4.08 (brs, 1H), 3.46–
3.33 (m, 1H), 3.13 (ddd, J ¼ 16:7, 7.8, 3.2 Hz, 1H), 2.92 (ddd,
J ¼ 18:6, 7.7, 3.2 Hz, 1H), 2.74–2.54 (m, 3H); 13C NMR (CDCl3)
ꢁ 209.7, 144.5, 134.9, 131.2, 130.8, 130.7, 126.9, 119.8, 118.5,
111.5, 78.8, 43.7, 32.8, 27.1; HRMS (CI) Found m/z: 228.1023,
Calcd for C14H14NO2 ðM þ HÞþ: 228.1025.
9
a) T. Mukaiyama, T. Nakagawa, H. Fujisawa, Chem. Lett.
2003, 32, 56. b) T. Nakagawa, H. Fujisawa, Y. Nagata, T.
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4-Allyl-4-hydroxy-3-chromanone (3d): Pale yellow oil; IR
(neat, cmꢃ1) 3502, 3078, 2916, 1736, 1639, 1608, 1483, 1051,
924; 1H NMR (CDCl3) ꢁ 7.53 (dd, J ¼ 7:6, 1.6 Hz, 1H), 7.29 (td,
J ¼ 7:6, 1.6 Hz, 1H), 7.14 (t, J ¼ 7:6 Hz, 1H), 7.02 (d, J ¼ 7:6
Hz, 1H), 5.77–5.67 (m, 1H), 5.15–5.07 (m, 2H), 4.78 (d, J ¼
18:6 Hz, 1H), 4.48 (d, J ¼ 18:6 Hz, 1H), 3.64 (s, 1H), 2.69–2.59
(m, 2H); 13C NMR (CDCl3) ꢁ 209.2, 152.9, 131.0, 129.4, 128.2,
126.0, 123.7, 119.9, 117.6, 77.3, 71.0, 43.5; HRMS (CI) Found
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This study was supported in part by the Grant of the 21st
Century COE Program, Ministry of Education, Culture, Sports,
Science and Technology (MEXT).
The authors wish to thank Ms. Noriko Horie, Mitsui Chemi-
cal Analysis & Consulting Service INC. for her kind help with
IR and High resolution mass spectrometry analyses.
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