Gold-catalyzed cyclizations of 1,7-enynes

Article abstract of DOI:10.1055/s-2007-984502

The skeletal rearrangement as well as the hydroxy- and methoxycyclization of 1,7-enynes proceeds at room temperature with cationic gold(I) catalysts. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2007-984502

CLUSTER
1753
Gold-Catalyzed Cyclizations of 1,7-Enynes
1
,7-Enyne Cycliza
o
tion emí Cabello, Cristina Rodríguez, Antonio M. Echavarren*
Institute of Chemical Research of Catalonia (ICIQ), Av. Països Catalans 16, 43007 Tarragona, Spain
Fax +34(977)920225; E-mail: aechavarren@iciq.es
Received 16 March 2007
Au(I)
Abstract: The skeletal rearrangement as well as the hydroxy- and
R'
– Au(I)
methoxycyclization of 1,7-enynes proceeds at room temperature
with cationic gold(I) catalysts.
R'
Z
R
Z
R
H
Key words: gold, enynes, alkynes, cycloisomerization, rearrange-
ments
H
5
6
R
Z
Au(I)
Au(I)
Gold complexes are the most active homogeneous cata-
lysts for the cyclizations of enynes to afford a variety of
cycloisomerized compounds.1–4 For gold(I), selective
activation of the alkyne of 1,6-enynes such as in 1 leads to
cyclopropyl gold carbenes 2,5 which in the absence of
nucleophiles evolve by intramolecular rearrangement to
give 1,3-dienes 3 and 4 (Scheme 1).6 In the first case,
products 3 arise by cleavage of the alkene (single cleav-
age), whereas for the formation of products 4 the alkyne
has also been cleaved (double cleavage rearrangement). In
the presence of alcohols or water products of alkoxy- or
hydroxycyclization 7 and 8 are obtained.7–9 Enynes sub-
stituted at the alkyne can cyclize by endo pathways via 5
to give cyclopropanes 65,10 or products of endocyclic
skeletal rearrangement.11 Recently, addition of carbon
nucleophiles to intermediates 211 as well as opening of
intermediates 5 to form seven-membered ring products
have also been observed.12 Related intramolecular hy-
droxycyclizations and sulfonamido cyclizations13 have
been observed from 1,5-enynes.
3
R'
R
H
R' = H
R
Z
+
Z
R
H
Z
2
1
4
NuH
Z
Z
H
+
R
R
H
Nu
H
Nu
7
8
Scheme 1
on the gold(I)-catalyzed hydroxy- and methoxycycliza-
tion of acyclic 1,7-enynes. In addition, we examined the
gold(I)-catalyzed cyclization of 1,7-enynes in the absence
of nucleophiles to determine the nature (single vs. double
cleavage) of their skeletal rearrangement. As catalysts, we
chose gold(I) complexes 12–1625–27 (Figure 1), which
were shown to be particularly active in the cyclization of
1,6-enynes.
The skeletal rearrangement of 1,7-enynes has been less
studied. Murai and Chatani reported the first example of a
skeletal rearrangement of a 1,7-enyne using [RuCl(CO)2]2
as catalyst.14 Similar results have been obtained using
PtCl2,15 PtCl4,16 [IrCl(CO)3]n,17 GaCl3,18 and InCl3.19 With
the exception of rearrangements catalyzed by GaCl3,
which can proceed with 10–20 mol% catalyst at 23–
40 °C, all other metals catalyzed the process at higher
temperatures (80–110 °C).20 Recently, a few examples of
skeletal rearrangement and hydroxylation of 1,7-enynes
have been reported using Au(I)21 and Hg(II)22 as catalysts,
respectively.
RO
O
HO
H
H
PhO2S
PhO2S
10
9
PhO2S
PhO2S
As part of a program on the synthesis of the hernandulcin
(9), a sweet bisabolane-type sesquiterpene,23,24 we
planned to synthesize 10 by using the metal-catalyzed
hydroxy- or alkoxycyclization of dienyne 11 as the key
step (Scheme 2). Herein we report our preliminary results
11
Scheme 2
The cyclization of 1,7-enynes bearing cyclic alkenes leads
to cyclobutenes by formal [2+2] cycloaddition.6,28 In
contrast, enynes 17a–h react smoothly with 2 mol% of
gold(I) catalyst 12 in CH2Cl2 at room temperature to give
SYNLETT 2007, No. 11, pp 1753–1758
Advanced online publication: 25.06.2007
DOI: 10.1055/s-2007-984502; Art ID: Y01207ST
© Georg Thieme Verlag Stuttgart · New York
0
3
.0
7
.2
0
0
7

1754
N. Cabello et al.
CLUSTER
t-Bu
formed by catalyst 12 into 18a-d1, which corresponds to
the product of a single-cleavage mechanism. This behav-
ior is similar to that observed for 1,6-enyne 19-d1, which
affords a 2:1 mixture of 20-d1 and 21-d1 under these con-
ditions. It is interesting to note that in this case the exo-
cyclic rearrangement takes place exclusively by the
single-cleavage pathway to give 20-d1, which is in con-
trast with that found in the cyclization of the diethyl ester
analogue of 19-d1 with Ru(II)14 and Pt(II),15a,20 but is
similar to that obtained in the rearrangement with InCl3
(toluene, 80 °C).19
t-Bu
O
P AuCl
12: [Au(PPh3)(NCMe)]SbF6
3
13
Cy
Cy
t-Bu
t-Bu
SbF6
P
Au Cl
P
Au NCMe
R
R'
R
16
14: R = R' = i-Pr
15: R = OMe, R' = H
Figure 1
D
D
E
E
E
12 (2 mol%)
skeletal-rearrangement products 18a–h in good to excel-
lent yields (Table 1).29,30 In general, reactions were very
clean with cationic catalyst 12 and, except for the trans-
formations of 17a and 17e (Table 1, entries 1 and 5,
respectively), the starting 1,7-enyne was consumed in less
than 5 minutes. In addition, in contrast with other
catalysts,21 no isomerization of the final products was
observed with complex 12. No precipitation of gold metal
was observed in these reactions.
E
CH2Cl2, r.t.,
48 h (57%)
18a-d1
17a-d1
D
D
E
E
D
12 (5 mol%)
E
E
+
E
CH2Cl2, r.t.,
1 h (50%)
E
20-d1
21-d1
19-d1
2:1
E = CO2Me
The above results are consistent with rearrangements of
1,7-enynes proceeding by the single-cleavage mecha-
nism. In order to ascertain if substrate 17a, which bears a
terminally unsubstituted enyne, also undergoes cycliza-
tion by this mechanism, we studied the rearrangement of
17a-d1 (Scheme 3). This substrate was cleanly trans-
Scheme 3
The hydroxy- and methoxycyclization of 17g proceeded
with a variety of gold(I) catalysts (Table 2).31 Better re-
sults were obtained in these cases with gold(I) complexes
bearing bulky biphenylphosphines.32 The reaction in
aqueous acetone afforded mixtures of alcohol 22a and
rearranged diene 18g (Table 2, entries 1–5), whereas the
reaction in methanol led exclusively to the product of
methoxycyclization 22b (Table 2, entries 6 and 7).33 The
best results were obtained by using gold(I) complex 14 as
the precatalyst.
Table 1 Rearrangement of 1,7-Enynes 17a–h with Catalyst 12
R1
12 (2 mol%)
R2
Z
R2
Z
CH2Cl2, r.t.
R1
18a–h
17a: Z = C(CO2Me)2, R1 = R2 = H
Reaction of enyne 17f in aqueous acetone afforded alco-
hol as a single stereoisomer in moderate yield (Scheme 4),
along with the product of skeletal rearrangement 18f. The
configuration of alcohol 23 was assigned by analogy with
that of the reaction of 1,6-enynes.8
17b: Z = C(CO2Me)2, R1 = Me, R2 = H
17c: Z = C(CO2Me)2, R1 = Ph, R2 = H
17d: Z = C(CO2Me)2, R1 = R2 = Me
17e: Z = C(SO2Ph)2, R1 = Me, R2 = H
17f: Z = C(SO2Ph)2, R1 = Ph, R2 = H
17g: Z = C(SO2Ph)2, R1 = R2 = Me
17h: Z = NTs, R1 = R2 = Me
OH
14 (10 mol%)/
AgSbF6 (10 mol%)
Entry
Enyne
17a
Time
48 h
Product (yield, %)
18a (72)
Ph
H
+
18f
Z
Z
1
2
3
4
5
6
7
8
H2O, acetone,
r.t., 48 h
Ph
(18%)
17ba
17c
5 min
5 min
5 min
13 h
18ba (98)
18c (81)
17f
23 (48%)
Scheme 4
17d
17ea
17f
18d (86)
For the synthesis of dienyne 27, homogeraniol (25) was
prepared by the method of Kocienski (Scheme 5).34 The
synthesis of dienyne 11 was similarly achieved from
homonerol (30), via thioacetal 29 prepared from nerol
(28) by the method of Murahashi.35
18ea (74)
18f (70)
5 min
5 min
5 min
17g
18g (92)
The hydroxycyclization of 27 and 11 (Table 3 and
Table 4) gave stereospecifically 31a and 10a, respec-
tively, although the isolated yields were low. In these
17h
18h (92)
a A 9:1 E/Z mixture.
Synlett 2007, No. 11, 1753–1758 © Thieme Stuttgart · New York

CLUSTER
1,7-Enyne Cyclization
1755
Table 2 Hydroxy- and Methoxycyclization of 1,7-Enyne 17ga
OR
ROH
+
18g
PhO2S
PhO2S
PhO2S
PhO2S
[Au], r.t.
17g
22a: R = H
22b: R = Me
Entry
ROHb
[Au] (mol%)
12
Time (h)
12
22:18g (ratio)
Yield of 22 (%)
c
1
2
3
4
5
6
7
H2O
1.4:1
5:1
–
H2O
14/AgSbF6 (5)
14/AgSbF6 (10)
15/AgSbF6 (10)
16 (10)
96
56
44
H2O
24
2:1
c
H2O
12
3:1
–
c
H2O
12
2.5:1
>20:1
>20:1
–
MeOH
MeOH
14/AgSbF6 (5)
14/AgSbF6 (10)
144
36
88
70
a Reactions run at r.t. until quantitative conversion (determined by 1H NMR).
b 2 Equiv of H2O in acetone, or neat MeOH.
c Yield was not determined.
reactions, the skeletal-rearrangement products 32 and 33 Somewhat surprisingly, highly electrophilic gold(I) cata-
were obtained as the major products.36 No reaction was lyst generated in situ from 1327 led to no conversion
observed when dienyne 27 was heated with PtCl2 (10 (Table 3, entry 5).
mol%) in aqueous acetone at 60 °C for 48 hours. The
The above results are consistent with reaction of 1,7-
methoxycyclizations of 27 and 11 were more efficient and
enynes by selective activation of the alkyne by Au(I) 34
provided 31b and 10b stereospecifically in good yields
leading to cyclopropyl gold(I)-carbenes 35, which suffer
(Table 3, entries 6 and 7, and Table 4, entry 2). The best
single-cleavage rearrangement to give dienes 36
results were also obtained in these cases with the catalyst
(Scheme 6). These reactions proceed at room temperature
prepared by chloride abstraction from gold(I) complex 14.
with just 2 mol% cationic gold(I) catalyst and are the
Table 3 Hydroxy- and Methoxycyclization of Dienyne 27a
OR
H
Z
ROH
[Au], r.t.
+
Z
Z
31a: R = H
31b: R = Me
32
Z = C(SO2Ph)2
27
Entry
ROHb
H2O
[Au] (mol%)
Time (h)
31:32 (ratio)
Yield (%)
1
3
4
5
6e
7
14/AgSbF6 (10)
15/AgSbF6 (10)
16 (10)
48
48
48
36
12
15
1:4
1:4
1:5
31a (10), 32 (44)
c
H2O
–
c
H2O
–
d
d
MeOH
MeOH
MeOH
13/AgSbF6 (10)
14/AgSbF6 (10)
14/AgSbF6 (10)
–
–
>20:1
>20:1
31b (55)
31b (72)
a Reactions run at r.t. until quantitative conversion (determined by 1H NMR).
b 2 Equiv of H2O in acetone or neat MeOH.
c Yield was not determined.
d No reaction.
e Reaction run at 40 °C.
Synlett 2007, No. 11, 1753–1758 © Thieme Stuttgart · New York

1756
N. Cabello et al.
CLUSTER
Table 4 Hydroxy- and Methoxycyclization of Dienyne 11a
RO
H
Z
ROH
+
Z
Z
[Au], r.t.
10a: R = H
10b: R = Me
33
Z = C(SO2Ph)2
11
Entry
ROHb
H2O
[Au] (mol%)
Time (h)
48
10:33 (ratio)
1:1.4
Yield (%)
1
2
14/AgSbF6 (10)
14/AgSbF6 (10)
10a (20), 33 (30)
10b (70)
MeOH
48
>20:1
a Reactions run at r.t. until quantitative conversion (determined by 1H NMR).
b 2 Equiv of H2O in acetone or neat MeOH.
Au(I)
HO
Au(I)
O
I2, PPh3, py
Ref. 34
R1
R2
R1
R2
Z
Z
CH2Cl2, 0 °C (86%)
24
25
R2
Z
R1
H
35
34
36
1. (PhO2S)2CH2,
NaH, DMF,
0 °C to r.t.
I
ROH
Z
2. NaH,
CH2Br
Z
26
27: Z = C(SO2Ph)2
OR
R1
(54%, 2 steps)
H
R2
37
Ref. 35
Scheme 6
S
28
29
HO
S
Acknowledgment
1. Br2, PPh3, py
CH2Cl2, 0 °C (50%)
1. MeI, aq CaCO3
We thank the MEC (project CTQ2004-02869 and Consolider Inge-
nio 2010, Grant CSD2006-0003 and Torres Quevedo contract to
N.C.), the AGAUR (2005 SGR 00993), Farmiva (postdoctoral fel-
lowship to C.R.), and the ICIQ Foundation for financial support.
2. DIBAL-H, CH2Cl2,
–78 °C to r.t.
(61%, 2 steps)
2. (PhO2S)2CH2,
NaH, DMF, 0 °C to r.t.
30
OH
3. NaH,
CH2Br
(30%, 2 steps)
References and Notes
(1) Jiménez-Núñez, E.; Echavarren, A. M. Chem. Commun.
2007, 333.
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Z
11: Z = C(SO2Ph)2
Scheme 5
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Rev. 2004, 33, 431.
(5) Nieto-Oberhuber, C.; López, S.; Jiménez-Núñez, E.;
Echavarren, A. M. Chem. Eur. J. 2006, 11, 5916.
(6) Nieto-Oberhuber, C.; López, S.; Muñoz, M. P.; Cárdenas, D.
J.; Buñuel, E.; Nevado, C.; Echavarren, A. M. Angew. Chem.
Int. Ed. 2005, 44, 6146.
fastest skeletal rearrangements of 1,7-enynes that have
been described. In the presence of water or methanol,
adducts 37 are stereospecifically obtained. Interestingly,
in contrast with that obtained with 1,5-enyne systems,7a,26
no intramolecular cyclopropanation has been observed
with dienyne 27. The synthesis of hernandulcin (9) is in
progress by using the gold(I)-catalyzed alkoxycyclization
of dienyne 11.
Synlett 2007, No. 11, 1753–1758 © Thieme Stuttgart · New York

CLUSTER
1,7-Enyne Cyclization
1757
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and the mixture was stirred for the time and at the
temperature stated in Table 1. The resulting mixture was
filtered through SiO2 and the solvent was evaporated to give
the corresponding product.
(30) Selected Characterization Data
Compound 18b (9:1 E/Z): yellow oil. 1H NMR (400 MHz,
CDCl3): d = 6.04 (d, J = 15.7 Hz, 1 H), 5.64 (tt, J = 7.5, 1.4
Hz, 1 H), 5.55 (br s, 1 H), 2.67 (s, 2 H), 3.74 (s, 6 H), 2.18
(br s, 2 H), 2.13 (q, J = 5.6 Hz, 2 H), 1.75 (d, J = 6.6 Hz, 3
H). 13C NMR (100 MHz, CDCl3): d = 172.2, 133.6, 133.1,
124.7, 122.6, 53.5, 52.8, 30.3, 27.8, 22.9, 18.4. ESI-HRMS:
m/z calcd for C13H18NaO4 [M + Na]+: 261.1103; found:
261.1111.
Compound 18c: colorless oil. 1H NMR (400 MHz, CDCl3):
d = 7.40 (d, J = 7.6 Hz, 2 H), 7.31 (t, J = 7.6 Hz, 2 H), 7.20
(t, J = 7.6 Hz, 1 H), 6.78 (d, J = 16.3 Hz, 1 H), 6.52 (d,
J = 16.3 Hz, 1 H), 5.84 (s, 1 H), 3.76 (s, 6 H), 2.85 (s, 2 H),
2.29 (s, 2 H), 2.19 (t, J = 6.3 Hz, 2 H). 13C NMR (100 MHz,
CDCl3): d = 172.1, 137.7, 133.2, 131.2, 128.7, 128.6, 127.3,
126.4, 125.9, 53.5, 52.9, 30.3, 27.7, 23.3. ESI-HRMS: m/z
calcd for C18H20NaO4 [M + Na]+: 323.1259; found:
323.1269.
Compound 18e: colorless oil. 1H NMR (400 MHz, CDCl3):
d = 8.03 (dd, J = 8.2, 1.4 Hz, 4 H), 7.69 (dq, J = 14.4, 6.6 Hz,
1 H), 7.56 (tt, J = 8.2, 1.7 Hz, 1 H), 5.98 (d, J = 15.7 Hz, 1
H), 5.57 (s, 1 H), 5.46 (dq, J = 6.6, 15.7 Hz, 1 H), 2.94 (s, 2
(14) Chatai, N.; Morimoto, T.; Muto, T.; Murai, S. J. Am. Chem.
Soc. 1994, 116, 6049.
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Organometallics 1996, 15, 901. (b) Miyanohana, Y.; Inoue,
H.; Chatani, N. J. Org. Chem. 2004, 69, 8541.
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2003, 24, 887.
H), 2.44–2.42 (m, 4 H), 1.74 (dd, J = 0.7, 6.6 Hz, 3 H). 13
C
NMR (100 MHz, CDCl3): d = 136.9, 134.7, 132.8, 131.4,
130.3, 128.8, 124.9, 122.9, 87.9, 25.7, 23.8, 22.8, 18.4. ESI-
HRMS: m/z calcd for C21H22NaO4S2 [M + Na]+: 425.0857;
found: 425.0853.
(17) Chatani, N.; Inoue, H.; Morimoto, T.; Muto, T.; Murai, S.
J. Org. Chem. 2001, 66, 4433.
Compound 18f: colorless oil. 1H NMR (400 MHz, CDCl3):
d = 8.06 (dd, J = 8.4, 1.3 Hz, 1 H), 7.69 (tt, J = 7.5, 1.1 Hz,
1 H), 7.56 (t, J = 8.2 Hz, 4 H), 7.38–7.31 (m, 4 H), 7.26–7.22
(m, 1 H), 6.71 (d, J = 16.4 Hz, 1 H), 6.32 (d, J = 16.3 Hz, 1
H), 5.80 (br s, 1 H), 3.12 (s, 2 H), 2.53 (br s, 2 H), 2.49 (d,
J = 5.6 Hz, 2 H). 13C NMR (100 MHz, CDCl3): d = 137.3,
136.8, 134.8, 131.4, 130.4, 130.3, 128.9, 128.7, 127.7,
126.5, 126.2, 87.7, 25.5, 23.9, 23.4. ESI-HRMS: m/z calcd
for C26H24NaO4S2 [M + Na]+: 487.1014; found: 487.1004.
Compound 18g: colorless oil. 1H NMR (400 MHz, CDCl3):
d = 8.03 (d, J = 7.8 Hz, 4 H), 7.69 (t, J = 7.4 Hz, 2 H), 7.56
(t, J = 7.8 Hz, 4 H), 5.45 (s, 1 H), 5.35 (s, 1 H), 2.80 (s, 2 H),
2.41 (s, 4 H), 1.73 (s, 3 H), 1.69 (s, 3 H). 13C NMR (100
MHz, CDCl3): d = 137.0, 135.4, 134.6, 131.4, 128.8, 125.3,
123.8, 88.1, 29.7, 26.7, 23.3, 22.7, 19.9. ESI-HRMS: m/z
calcd for C22H24NaO4S2 [M + Na]+: 439.1014; found:
439.1013.
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Chem. Eur. J. 2006, 11, 1694.
Compound 18h: light yellow oil. 1H NMR (400 MHz,
CDCl3): d = 8.03 (d, J = 7.8 Hz, 4H), 7.69 (t, J = 7.4 Hz, 2
H), 7.56 (t, J = 7.8 Hz, 4 H), 5.45 (s, 1 H), 5.35 (s, 1 H), 2.80
(s, 2 H), 2.41 (s, 4 H), 1.73 (s, 3 H), 1.69 (s, 3 H). 13C NMR
(100 MHz, CDCl3): d = 143.6, 136.1, 133.6, 131.9, 129.8,
127.9, 123.3, 122.4, 47.8, 42.7, 26.8, 25.5, 21.7, 19.8. ESI-
HRMS: m/z calcd for C16H21NNaO2S [M + Na]+: 314.1191;
found: 314.1185.
(31) General Procedure for Au(I)-Catalyzed Intramolecular
Hydroxycyclization or Alkoxycyclization
(27) López, S.; Herrero-Gómez, E.; Pérez-Galán, P.; Nieto-
Oberhuber, C.; Echavarren, A. M. Angew. Chem. Int. Ed.
2006, 45, 6029.
The enyne was added to a mixture of the Au(I) catalyst (5–
10 mol%) and silver(I) salt (5–10 mol%) [or the
(28) (a) Trost, B. M.; Trost, M. K. Tetrahedron Lett. 1991, 32,
3647. (b) Fürstner, A.; Stelzer, F.; Szillat, H. J. Am. Chem.
Soc. 2001, 123, 11863.
(29) General Procedure for Au(I)-Catalyzed Skeletal
Rearrangement of Enynes
corresponding cationic Au(I) complex] in the stated solvent
[3 mL of MeOH or 3 mL of aq acetone (2 equiv H2O)] and
the mixtures were stirred under the stated conditions. The
resulting mixture was filtered through SiO2, and the solvent
was evaporated. Flash column chromatography (3:1
hexane–EtOAc) gave the corresponding product.
To a mixture of the cationic Au(I) complex (2 mol%) in dry
CH2Cl2 (1 mL) was added the enyne in dry CH2Cl2 (1 mL)
Synlett 2007, No. 11, 1753–1758 © Thieme Stuttgart · New York

1758
N. Cabello et al.
CLUSTER
(32) (a) Strieter, E. R.; Blackmond, D. G.; Buchwald, S. L. J. Am.
Chem. Soc. 2003, 125, 13978. (b) Walker, S. D.; Border, T.
E.; Martinelli, J. R.; Buchwald, S. L. Angew. Chem. Int. Ed.
2004, 43, 1871. (c) Kaye, S.; Fox, J. M.; Hicks, F. A.;
Buchwald, S. L. Adv. Synth. Catal. 2001, 343, 789.
(33) Compound 22b: 1H NMR (400 MHz, CDCl3): d = 8.07 (dd,
J = 1.2, 7.4 Hz, 2 H), 7.98 (dd, J = 1.2, 7.4 Hz, 2 H), 7.70–
7.66 (m, 2 H), 7.56 (t, J = 7.7 Hz, 4 H), 5.03 (s, 1 H), 4.92 (s,
1 H), 3.24 (d, J = 15.1 Hz, 1 H), 2.92 (s, 3 H), 2.88 (d,
J = 15.1 Hz, 1 H), 2.63–2.58 (m, 1 H), 2.26 (m, 2 H), 2.02–
1.97 (m, 2 H), 1.12 (s, 3 H), 1.05 (s, 3 H). 13C NMR (100
MHz, CDCl3): d = 140.3, 137.4, 136.9, 134.52, 134.48,
131.64, 131.63, 128.8, 128.6, 117.5, 89.2, 77.4, 48.9, 48.5,
34.2, 24.9, 23.4, 22.8, 21.9. ESI-HRMS: m/z calcd for
C23H28NaO5S2 [M + Na]+: 471.1276; found: 471.1270.
Compound 23: 1H NMR (400 MHz, CDCl3): d = 8.09 (d,
J = 7.6 Hz, 2 H), 8.05 (d, J = 7.6 Hz, 2 H), 7.75–7.70 (m, 2
H), 7.64 (t, J = 7.9 Hz, 2 H), 7.59 (t, J = 7.9 Hz, 2 H), 7.35–
7.29 (m, 5 H), 4.97 (d, J = 5.7 Hz, 1 H), 4.90 (s, 1 H), 4.88
(s, 1 H), 3.15 (d, J = 15.6 Hz, 1 H), 2.92 (d, J = 15.6 Hz, 1
H), 2.65–2.56 (m, 2 H), 2.36–2.26 (m, 2 H), 2.25–2.16 (m, 2
H). 13C NMR (100 MHz, CDCl3): d = 142.8, 140.9, 136.6,
136.5, 134.8, 131.7, 131.6, 128.8, 128.7, 127.8, 126.3,
114.5, 88.5, 74.3, 53.6, 47.5, 33.7, 31.1, 24.4. ESI-HRMS:
m/z calcd for C26H26NaO5S2 [M + Na]+: 505.1119; found:
505.1115.
(100 MHz, CDCl3): d = 140.4, 137.4, 136.9, 134.6, 134.5,
131.8, 131.7, 128.8, 128.6, 124.4, 117.5, 89.2, 79.2, 48.5,
45.4, 35.2, 34.4, 25.9, 25.1, 22.9, 21.5, 20.6, 17.9. ESI-
HRMS: m/z calcd for C28H36NaO5S2 [M + Na]+: 539.1902;
found: 539.1884.
Compound 10a: colorless oil. 1H NMR (400 MHz, CDCl3):
d = 8.06 (d, J = 7.6 Hz, 2 H), 8.03 (d, J = 7.4 Hz, 2 H), 7.71
(t, J = 7.2 Hz, 2 H), 7.59 (t, J = 7.9 Hz, 4 H), 5.08 (m, 1 H),
5.01 (s, 1 H), 3.24 (d, J = 15.4 Hz, 1 H), 2.92 (d, J = 15.4 Hz,
1 H), 2.55 (dt, J = 15.5, 4.6 Hz, 1 H), 2.37 (t, J = 7.9 Hz, 1
H), 2.32–2.25 (m, 1 H), 2.07–1.93 (m, 4 H), 1.69 (s, 3 H),
1.62 (s, 3 H), 1.53 (br s, 1 H), 1.46 (t, J = 8.2 Hz, 2 H), 1.12
(s, 3 H). 13C NMR (CDCl3): d = 139.9, 137.0, 136.6, 134.7,
132.1, 131.8, 131.7, 128.8, 128.7, 124.4, 118.6, 88.5, 74.6,
48.2, 40.1, 34.2, 25.9, 25.3, 24.2, 22.5, 21.8, 17.9. ESI-
HRMS: m/z calcd for C27H34NaO5S2 [M + Na]+: 525.1745;
found: 525.1743.
Compound 10b: colorless oil. 1H NMR (400 MHz, CDCl3):
d = 8.07 (d, J = 7.4 Hz, 2 H), 8.03 (d, J = 7.3 Hz, 2 H), 7.70
(t, J = 7.9 Hz, 2 H), 7.59 (td, J = 8.2, 1.8 Hz, 4 H), 5.05 (m,
3 H), 3.22 (d, J = 15.3 Hz, 1 H), 3.02 (s, 3 H), 2.91 (d,
J = 15.3 Hz, 1 H), 2.61–2.55 (m, 1 H), 2.46 (t, J = 7.7 Hz, 1
H), 2.33–2.26 (m, 1 H), 1.99–1.85 (m, 4 H), 1.70 (s, 3 H),
1.61 (s, 3 H), 1.45 (t, J = 8.6 Hz, 2 H), 1.11 (s, 3 H). 13
C
NMR (100 MHz, CDCl3): d = 139.6, 137.2, 136.9, 134.6,
131.7, 128.8, 128.7, 124.5, 117.7, 88.9, 79.3, 48.7, 45.3,
35.0, 34.9, 25.9, 25.4, 22.5, 22.0, 19.7, 17.9. ESI-HRMS:
m/z calcd for C28H36NaO5S2 [M + Na]+: 539.1902; found:
539.1890.
(34) Kocienski, P.; Wadman, S.; Cooper, K. J. Org. Chem. 1989,
54, 1215.
(35) Tanigawa, Y.; Kanamaru, H.; Sonoda, A.; Murahashi, S.-I.
J. Am. Chem. Soc. 1977, 99, 2361.
Compound 32: colorless oil. 1H NMR (400 MHz, CDCl3):
d = 8.05 (d, J = 7.5 Hz, 4 H), 7.70 (t, J = 7.6 Hz, 2 H), 7.58
(t, J = 7.9 Hz, 4 H), 5.50 (s, 1 H), 5.37 (s, 1 H), 5.10 (t,
J = 6.2 Hz, 1 H), 2.84 (s, 2 H), 2.42 (s, 4 H), 2.12–2.01 (m,
4 H), 1.70 (s, 6 H), 1.63 (s, 3 H). 13C NMR (100 MHz,
CDCl3): d = 138.8, 137.0, 134.7, 131.9, 131.4, 129.9, 128.8,
125.1, 124.1, 123.9, 88.1, 40.6, 29.7, 26.9, 25.9, 23.3, 22.8,
18.3, 17.9. ESI-HRMS: m/z calcd for C27H32NaO4S2 [M +
Na]+: 507.1640; found: 507.1646.
(36) Compound 31a: 1H NMR (400 MHz, CDCl3): d = 8.07 (dd,
J = 1.1, 8.5 Hz, 2 H), 8.02 (dd, J = 1.1, 8.5 Hz, 2 H), 7.72–
7.68 (m, 2 H), 7.60–7.55 (m, 4 H), 5.08 (overlap. t, J = 7.1
Hz, 1 H), 5.06 (overlap. s, 1 H), 4.94 (s, 1 H), 3.29 (d,
J = 15.4 Hz, 1 H), 2.89 (d, J = 15.4 Hz, 1 H), 2.59–2.54 (m,
1 H), 2.34–2.26 (m, 2 H), 2.04–1.98 (m, 4 H), 1.69 (s, 3 H),
1.61 (s, 3 H), 1.51–1.43 (m, 1 H), 1.49–1.36 (m, 2 H), 1.13
(s, 3 H). 13C NMR (100 MHz, CDCl3): d = 140.2, 137.1,
136.7, 134.6, 134.6, 132.3, 131.8, 131.7, 128.8, 128.7,
124.2, 118.3, 88.7, 75.1, 48.5, 39.7, 34.1, 25.9, 25.3, 25.2,
23.0, 21.4, 17.9. ESI-HRMS: m/z calcd for C27H34NaO5S2
[M + Na]+: 525.1745; found: 525.1767.
Compound 33: colorless oil. 1H NMR (400 MHz, CDCl3):
d = 8.04 (d, J = 8.5 Hz, 4 H), 7.70 (t, J = 6.8 Hz, 2 H), 7.57
(t, J = 8.0 Hz, 4 H), 5.49 (s, 1 H), 5.38 (s, 1 H) 5.07 (t, J = 6.4
Hz, 1 H), 2.79 (s, 2 H), 2.40 (s, 4 H), 2.10–2.03 (m, 4 H),
1.73 (s, 3 H), 1.68 (s, 3 H), 1.59 (s, 3 H). 13C NMR (100
MHz, CDCl3): d = 139.2, 136.9, 134.7, 134.6, 132.0, 131.8,
131.4, 129.8, 128.8, 128.7, 125.9, 124.1, 123.2, 88.0, 48.6,
33.2, 29.7, 27.2, 25.9, 23.9, 23.3, 22.7, 17.8. ESI-HRMS:
m/z calcd for C27H32NaO4S2 [M + Na]+: 507.1640; found:
507.1637.
Compound 31b: colorless oil. 1H NMR (400 MHz, CDCl3):
d = 8.10 (d, J = 7.3 Hz, 2 H), 8.01 (d, J = 7.3 Hz, 2 H), 7.72–
7.68 (m, 2 H), 7.59 (td, J = 7.7, 2.5 Hz, 4 H), 5.07 (m, 2 H),
4.92 (s, 1 H) 3.25 (d, J = 15.1 Hz, 1 H), 2.96 (s, 3 H), 2.89
(d, J = 15.1 Hz, 1 H), 2.65–2.58 (m, 1 H), 2.44 (t, J = 6.5 Hz,
1 H), 2.34–2.27 (m, 1 H), 2.02–1.86 (m, 4 H), 1.69 (s, 3 H),
1.61 (s, 3 H), 1.54–1.49 (m, 2 H), 1.06 (s, 3 H). 13C NMR
Synlett 2007, No. 11, 1753–1758 © Thieme Stuttgart · New York

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