Br?nsted acid-mediated ring-opening reactions of methylenecyclopropanes: A dramatic counter ion effect

Article abstract of DOI:10.1016/j.tet.2004.09.105

We report herein two different ring-opening patterns of methylenecyclopropanes (MCPs) in the presence of two Br?nsted acids heptadecafluorooctane-1-sulfonic acid (C₈F₁₇SO ₃H) and toluene p-sulfonic acid (TsOH) under mild conditions: (a) the ring-opening of MCPs by H₂O and subsequent etherification give the corresponding homoallylic ethers in the presence of heptadecafluorooctane-1- sulfonic acid; (b) the direct ring-opening of MCPs by the Br?nsted acid gives the corresponding homoallylic alcohol derivatives in the presence of toluene p-sulfonic acid. We report two different ring-opening patterns of methylenecyclopropanes (MCPs) in the presence of two Br?nsted acids heptadecafluorooctane-1-sulfonic acid (C₈F₁₇SO ₃H) and toluene p-sulfonic acid (TsOH): (a) the ring-opening of MCPs by H₂O and subsequent etherification give the corresponding homoallylic ethers in the presence of heptadecafluorooctane-1-sulfonic acid; (b) the direct ring-opening of MCPs by the Br?nsted acid gives the corresponding homoallylic alcohol derivatives in the presence of toluene p-sulfonic acid.

Full text of DOI:10.1016/j.tet.2004.09.105

Tetrahedron 60 (2004) 11895–11901
Brønsted acid-mediated ring-opening reactions of
methylenecyclopropanes: a dramatic counter ion effect
*
Li-Xiong Shao, Jin-Wen Huang and Min Shi
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences,
54 Fenglin Lu, Shanghai 200032, China
3
Received 23 July 2004; revised 20 September 2004; accepted 22 September 2004
Available online 19 October 2004
Abstract—We report herein two different ring-opening patterns of methylenecyclopropanes (MCPs) in the presence of two Brønsted acids
heptadecafluorooctane-1-sulfonic acid (C F17SO H) and toluene p-sulfonic acid (TsOH) under mild conditions: (a) the ring-opening of
8 3
MCPs by H O and subsequent etherification give the corresponding homoallylic ethers in the presence of heptadecafluorooctane-1-sulfonic
2
acid; (b) the direct ring-opening of MCPs by the Brønsted acid gives the corresponding homoallylic alcohol derivatives in the presence of
toluene p-sulfonic acid.
q 2004 Elsevier Ltd. All rights reserved.
1. Introduction
of heptadecafluorooctane-1-sulfonic acid (C F SO H) in
8 17 3
K
which the corresponding anion C F SO is a weak
8
17
3
Transition metal-catalyzed reactions of methylenecyclopro-
panes (MCPs) 1 have been widely explored in this area of
nucleophile; (b) the cyclopropyl ring of MCPs 1 can be
opened directly by the Brønsted acid toluene p-sulfonic acid
(TsOH) to give the homoallylic alcohol derivatives
1
study over the past decades. The attractive feature of these
compounds is their surprising stability along with a high
(
sulfonated homoallylic alcohols) in which the corres-
K
2
–4
level of strain. Strangely, less attention has been paid for
the Lewis acid or Brønsted acid-mediated reactions of
MCPs. In the continuum of Lewis acid or Brønsted acid-
ponding anion TsO is a strong nucleophile. In this paper
we wish to report the full details of these interesting results
5
(
Scheme 1).
mediated transformations of MCPs 1, we have found that
MCPs 1 can react with various reagents such as alcohols,
amines, and imines in a different ring-opening pattern.
6
These progresses stimulate us to investigate further the
Lewis acid or Brønsted acid-mediated ring-opening reac-
tions of MCPs 1. Recently, Yamamoto and co-workers
reported that the cyclopropyl ring of MCPs can be opened
by water to give the homoallylic alcohol under severe
reaction conditions, such as the use of a sealed pressure vial
under an inert gas atmosphere and at higher temperature
(
7
80 8C) without organic solvent. In the recent program of
Scheme 1. Ring-opening reactions of MCPs 1 in the presence of
17SO H/H O and TsOH$H O.
C
8
F
3
2
2
Brønsted acid-mediated transformations of MCPs 1, we
found that the corresponding anion (counter ion) of the
employed Brønsted acid played a significant role in the ring-
opening reactions under milder conditions: a) the cyclopro-
pyl ring of MCPs 1 can be opened by H O and subsequent
2
etherification to give the homoallylic ethers in the presence
2
. Results and discussion
At the outset of our investigation, the reaction of MCP 1a
with H O (1 equiv) was chosen as a model reaction and
carried out under various reaction conditions to confirm the
optimum reaction conditions. Table 1 shows the represen-
tative results. After several trials and errors, we were
2
Keywords: Methylenecyclopropanes (MCPs); Brønsted acid; Ring-opening
reaction; Toluene p-sulfonic acid (TsOH); Heptadecafluorooctane-1-
pleased to find out that the reaction of MCP 1a with H O in
2
sulfonic acid (C
8
F
17SO
Corresponding author. Tel.: C86 21 64163300x342; fax: 86 21
4166128; e-mail: mshi@pub.sioc.ac.cn
3
H).
*
the presence of C F SO H (0.1 equiv) gave the homo-
8
17
3
6
allylic ether 2a in 63% yield along with the homoallylic
0040–4020/$ - see front matter q 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2004.09.105

11896
L.-X. Shao et al. / Tetrahedron 60 (2004) 11895–11901
Table 1. The screening of the catalysts of the ring-opening of MCPs by
O and subsequent etherification
Table 3. Reaction of MCPs 1 with H
17SO H (0.3 equiv) in DCE
2
O (1.0 equiv) under the catalysis of
H
2
C
8
F
3
a
b
Entry
Catalyst
Zn(OTf)
Time/(h)
Yield/(%)
1
R /R
2
a
Entry
Time/h
Yield (%)
2
a
3a
2
3
1
2
3
4
5
6
7
8
2
72
72
72
72
72
72
72
72
72
48
24
24
24
24
—
Trace
—
Trace
Trace
Trace
49
—
1
2
3
4
5
6
1b, p-MeOC
1c, p-MeOC
1d, p-MeC
1e, o-ClC
1f, p-ClC
1g, p-FC
6
H
4
/p-MeOC
/C
/p-MeC
/C
/p-ClC
/p-FC
6
H
4
1
2
4
24
24
24
2b, 52
2c, 60
2d, 56
2e, 63
2f, 42
2g, 94
—
Trace
—
3e, 9
—
3g, 6
Cu(OTf)
Eu(OTf)
Sc(OTf)
Yb(OTf)
2
Trace
—
—
—
11
6
H
4
6 5
H
3
6
H
4
6
H
4
3
6
H
H
4
6
H
5
3
6
4
6 4
H
BF
CF
3
OEt
SO
2
6
H
4
6
H
4
3
3
H
5
Zr(OTf)
17SO
Zr(OTf)
4
21
63
48
71
67
11
36
Trace
8
a
Isolated yields.
9
C
8
F
3
H
c
10
11
12
13
14
4
Trace
—
Trace
25
18
homoallylic alcohol 3a (Table 2, entries 2–4). Traces of 2a
and 3a were obtained when 5.0 equiv of H O was used and
no reaction took place when 90.0 equiv of H O was used
2
c
C
C
C
C
8
F
8
F
8
F
8
F
17SO
3
H
H
H
H
d
2
17SO
17SO
17SO
3
3
3
c,e
c,f
(Table 2, entries 5, 6). Thus, these optimized reaction
conditions were 1.0 equiv of H O as the reagent, 0.3 equiv
a
b
c
d
e
f
2
Otherwise specified, 0.1 equiv of catalysts were used.
Isolated yields.
of C F SO H as the catalyst and DCE as the solvent.
3
8
17
0
1
.3 equiv of catalysts were used.
.0 equiv of catalyst was used.
In the following series of reactions, we examined the
reactivity of a variety of MCPs 1 under these optimized
conditions to surrey the generality of this reaction. The
results are shown in Table 3. We were delighted to find out
that the reactions proceeded smoothly to give the corres-
ponding homoallylic ether 2 as a sole product in good to
excellent yields in most cases except for MCP 1e and 1g in
which less than 10% of the homoallylic alcohol were
obtained (Table 3, entries 4 and 6). For MCPs 1b, 1c and
1d, in which electron-donating groups on the phenyl ring, the
reaction time was dramatically reduced (Table 3, entries
3
CH CN as the solvent.
n-Hexane as the solvent.
alcohol 3a in 8% yield within 72 h (Table 1, entry 9). The
product 2a was also obtained in somewhat lower yields,
either in the catalysis of CF SO H (0.1 equiv) or Zr(OTf)
4
(
other catalysts showed that Zn(OTf) , Cu(OTf) , Eu(OTf) ,
Sc(OTf) , Yb(OTf) and BF $OEt were not effective
2
promoters for this reaction (Table 1, entries 1–6). Further
screening showed that this reaction can complete within
3
3
0.1 equiv) (Table 1, entries 7 and 8). Investigation into
2
2
3
3
3
3
2
0
4 h to give 2a as a sole product in 71% yield when
.3 equiv of C F SO H was used (Table 1, entry 11) and
increasing the amount of C F SO H to 1.0 equiv gave 2a in
1–3). For the unsymmetric MCPs 1c and 1e, only one isomer
of the product 2 were obtained and we cannot explain these
phenomena at present stage (Table 3, entries 2 and 4) (see
8
17
3
8
17
3
1
13
their H and C NMR spectra in Supporting Information).
comparable yield also as a sole product (Table 1, entry 12).
In addition, product 2a was obtained in somewhat lower
yields along with 3a when CH CN and n-hexane were used
3
Interestingly, we found that the ring of MCPs 1 can be
opened by the corresponding anion when toluene p-sulfonic
acid monohydrate (TsOH$H O) was used as the Brønsted
acid reagent in 1,2-dichloroethane (DCE). The results are
shown in Table 4. As can be seen from Table 4, all reactions
as the solvents (Table 1, entries 13 and 14). Of the solvents
screened, 1,2-dichloroethane (DCE) proved to be a suitable
solvent, giving the best results.
2
The equivalents of H O were investigated for this ring-
2
opening reaction of MCPs. The results are summarized in
Table 2. As can be seen from Table 2, the best result was
obtained when 1.0 equiv H O was used (Table 2, entry 1).
Table 4. The reaction of toluene-4-sulfonic acid with various MCPs 1
2
Increasing the amount of H O to 2.0–4.0 equiv gave product
2
2
a in somewhat lower yields along with the formation of
Table 2. The effects of the amount of water used
1
R /R
2
a
Yield/% , 4 (E/Z)
Entry
Time/min
a
b
Entry
H
2
O (equiv)
Yield (%)
1
2
3
1a, C
6
H
5
/C
6
H
5
4
5
5
98
96
99 (1:1)
77
93 (7.8:1)
92
96
2
a
3a
1b, p-MeOC
1c, p-MeOC
1d, p-MeC
1e, o-ClC
1f, p-ClC
1g, p-FC
1h, p-EtOC
6
H
4
/p-MeOC
/C
/p-MeC
/C
/p-ClC
/p-FC
/Me
6
H
4
b
1
2
3
4
5
6
1.0
2.0
3.0
4.0
5.0
90.0
71
62
46
28
Trace
—
—
4
14
9
Trace
—
6
H
4
6
H
5
4
5
6
H
4
6
H
4
5
b
6
H
4
6
H
5
25
20
30
5
6
7
8
6
H
4
6 4
H
6
H
4
6
H
4
b
6
H
4
97 (2.5:1)
a
a
All reactions were carried out for 24 h.
Isolated yields.
Isolated yields.
Mixtures of (Z)- and (E)-isomers.
b
b

L.-X. Shao et al. / Tetrahedron 60 (2004) 11895–11901
11897
Scheme 2. Plausible reaction mechanism.
proceeded smoothly to give the homoallylic alcohol
derivatives 4 in excellent yields within 30 min. In this
case, the ambient H O did not participate in the ring-
2
Brønsted acid has dramatic effect on the ring-opening
modes of MCPs 1: the cyclopropyl ring of MCPs 1 can be
opened by water when the corresponding anion is a weak
nucleophile such as heptadecafluorooctane-1-sulfonic acid
(C F SO H) as the Brønsted acid mediator; and the
cyclopropyl ring of MCPs 1 also can be opened by the
corresponding anion when it is a strong nucleophile such as
toluene p-sulfonic acid (TsOH) as the Brønsted acid
mediator. Other Brønsted acids will be investigated in this
ring-opening system in the near future. In addition, efforts
are underway to elucidate the mechanistic details and
subsequent transformation thereof. Work along these lines
is currently in progress.
opening reaction. For the unsymmetric MCPs 1b, 1e and 1h,
the products 4b, 4e and 4h were obtained as mixtures of Z-
and E-isomers (Table 4, entries 3, 5 and 8). Using MeCN as
the solvent, a Ritter reaction product was obtained as the
8
17
3
8
by-product (Scheme 2).
1
The structures of products 2, 3 and 4 were determined by H
1
3
NMR and C NMR spectroscopic data, microanalysis and
HRMS.
A plausible mechanism for these two different ring-opening
reactions of MCPs 1 is shown in Scheme 2. The initial
protonation of MCPs 1 with Brønsted acid gives the
intermediate A. The cyclopropylmethyl cation intermediate
4. Experimental
A is further stabilized by two substituents on the double
bond. The intermediate A is attacked by H O if the
9
4.1. General remarks
2
corresponding anion of the Brønsted acid is a weak
nucleophile (in the case of C F SO ) to give product 3.
1
K
3
H NMR spectra were recorded on a 300 MHz spectrometer
in CDCl using tetramethylsilane as the internal standard.
8
17
3
Subsequent ring-opening nucleophilic attack of 3 to another
cation intermediate A gives product 2. The intermediate A
can also be attacked by the corresponding anion of the
Brønsted acid if it is a strong nucleophile (in the case of
Infrared spectra were measured on a PERKIN-ELMER 983
spectrometer. Mass spectra were recorded with a HP-5989
instrument and HRMS was measured by a Finnigan MA
mass spectrometer. Satisfactory CHN microanalyses were
obtained with a Carlo-Erba 1106 analyzer. Melting points
are uncorrected. All reactions were monitored by TLC with
Huanghai GF254 silica gel coated plates. Flash Column
Chromatography was carried out using 300–400 mesh silica
gel.
C
K
TsO ) to furnish product 4. In the case of MeCN as the
solvent, the cation intermediate A will be attacked by the
solvent (MeCN) to give the cation intermediate B which is
quenched by H O to give the Ritter-type by-product
2
(
Scheme 2).
4.2. General procedure for the ring-opening of MCPs by
H O and subsequent etherification in the catalysis of
3. Conclusion
2
heptadecafluorooctane-1-sulfonic acid (C F SO H)
8
17
3
In conclusion, we have found two different ring-opening
patterns of MCPs 1 in different Brønsted acid-mediated
systems. The nucleophilicity of the anion of the employed
Under an argon atmosphere, MCPs 1 (0.30 mmol), H O
2
(0.30 mmol) and C F SO H (0.1 mmol), were added into a
17
8
3

11898
L.-X. Shao et al. / Tetrahedron 60 (2004) 11895–11901
1
(m, 16H, Ar). C NMR (CDCl , 75 MHz, TMS): d 21.1,
3
flame-dried Schlenk tube with freshly distilled 1,2-dichloro-
ethane (DCE) (1.0 mL). The obtained white solid suspended
reaction mixture was stirred at room temperature. The
solvent was removed under reduced pressure and then the
residue was purified by a flash column chromatography.
3
21.2, 30.4, 70.5, 124.9, 125.7, 127.2, 128.7, 128.8, 129.8,
136.5, 137.1, 140.0, 142.8. MS (%) m/z 486 (M , 1.5), 265
C
C
(28.11), 234 (100). HRMS Calcd. for C H ONa (Maldi):
3
6 38
C
509.2817, Found: 509.2815 (MCNa ).
4.2.1. Di(4,4-diphenyl-but-3-en-1-yl) ether (2a). A white
solid, Mp: 103–106 8C; IR (neat): n 3078, 3054, 3023, 2856,
2
4.2.6. Di{4,4-[1-phenyl-1-(2-chlorophenyl)]-but-3-en-
1-yl} ether (2e). A yellow liquid, IR (CH Cl ): n 3080,
2
2
K1
778, 1945, 1889, 1734, 1597, 1494, 1443 cm ; H NMR
1
3055, 3024, 2947, 2858, 2791, 1937, 1800, 1730, 1597,
1494, 1473, 1445, 1434, 1360 cm . H NMR (CDCl ,
K1
1
(
CDCl , TMS, 300 MHz): d 2.43 (dt, JZ6.3, 7.2 Hz, 4H),
3
3
3
.51 (t, JZ6.3 Hz, 4H), 6.61 (t, JZ7.2 Hz, 2H), 7.20–7.39
TMS, 300 MHz): d 2.14 (dt, JZ6.9, 7.5 Hz, 4H), 3.39
(t, JZ6.9 Hz, 4H), 6.23 (t, JZ7.5 Hz, 2H), 7.09–7.21
1
3
(
m, 20H, Ar). C NMR (CDCl , 75 MHz, TMS): d 30.4,
3
1
3
7
1
0.4, 126.0, 126.90, 126.93, 127.2, 128.0, 128.2, 129.9,
39.9, 142.5, 143.1. MS (%) m/z 430 (M , 0.25), 237
(m, 16H, Ar), 7.33–7.36 (m, 2H, Ar). C NMR (CDCl3,
75 MHz, TMS): d 30.4, 69.9, 126.1, 126.7, 127.0, 127.1,
128.2, 128.6, 129.7, 131.7, 133.8, 138.5, 140.1, 140.3. MS
C
(
C H ONa (Maldi) : 453.2201, Found: 453.2189
50.68), 206 (75.71), 91 (100). HRMS Calcd. for
C
10
C
(%) m/z 498 (M , 0.20), 271 (83.66), 201 (100). HRMS
Calcd. for C H Cl ONa (Maldi): 521.1416, Found:
3
2
30
C
MCNa ).
C
(
3
2
28
2
C
21.1409 (MCNa ).
5
4
IR (neat): n 3344, 3055, 2926, 1493, 1443, 1047, 1031 cm
.2.2. 4,4-diphenyl-but-3-en-1-ol (3a). A colorless liquid;
K1
.
4.2.7. 1-Phenyl-1-(2-chlorophenyl)-but-3-en-1-ol (3e).
A yellow liquid, IR (CH Cl ): n 3321, 3056, 3024, 2928,
1
H NMR (CDCl , TMS, 300 MHz): d 2.40 (dt, JZ6.6,
3
2
2
K1
7
.5 Hz, 2H), 3.72 (t, JZ6.6 Hz, 2H), 6.11 (t, JZ7.5 Hz,
2881, 1945, 1712, 1594, 1560, 1494, 1473, 1445, 1434 cm
.
1
H), 7.17–7.40 (m, 10H, Ar). C NMR (CDCl , 75 MHz,
3
1
1
TMS): d 33.3, 62.6, 125.2, 127.07, 127.09, 127.2, 128.1,
H NMR (CDCl , TMS, 300 MHz): d 2.19 (dt, JZ6.6,
3
3
7.2 Hz, 2H), 3.65 (t, JZ6.6 Hz, 2H), 6.23 (t, JZ7.2 Hz,
C
28.2, 129.8, 139.8, 142.4, 144.2. MS (%) m/z 224 (M ),
13
1
1
2
1H), 7.12–7.25 (m, 8H, Ar), 7.37–7.40 (m, 1H, Ar).
NMR (CDCl , 75 MHz, TMS): d 33.4, 62.1, 126.17, 126.24,
C
93, 178, 165, 115. HRMS Calcd. for C H O (EI):
1
6
16
3
24.1201, Found: 224.1215.
126.5, 126.8, 127.3, 128.3, 128.8, 129.7, 131.6, 133.7,
1
HRMS Calcd. for C16H15ClONa (Maldi): 281.0733,
C
38.4, 140.0. MS (%) m/z 258 (M , 46.87), 227 (100).
C
4
(
2
.2.3. Di[4,4-bis(4-methoxyphenyl)-but-3-en-1-yl] ether
2b). A colorless liquid, IR (CH Cl ): n 3002, 2956, 2933,
907, 2836, 2052, 1730, 1645, 1604, 1510, 1462, 1248 cm
C
Found: 281.0704 (MCNa ).
2
2
K1
.
1
H NMR (CDCl , TMS, 300 MHz): d 2.39 (dt, JZ6.6,
4.2.8. Di[4,4-bis(4-chlorophenyl)-but-3-en-1-yl] ether
(2f). A bright yellow liquid, IR (CH Cl ): n 3044, 2857,
3
6
.9 Hz, 4H), 3.48 (t, JZ6.6 Hz, 4H), 3.78 (s, 3H, CH O),
3
2
2
K1
1
3
8
8
.81 (s, 3H, CH O), 5.99 (t, JZ6.9 Hz, 2H), 6.77 (d, JZ
2785, 1893, 1778, 1586, 1491, 1405 cm
.
H NMR
3
.7 Hz, 4H, Ar), 6.87 (d, JZ8.7 Hz, 4H, Ar), 7.10 (d, JZ
(CDCl , TMS, 300 MHz): d 2.38 (dt, JZ6.6, 7.5 Hz, 4H),
3
1
3
.7 Hz, 4H, Ar), 7.14 (d, JZ8.7 Hz, 4H, Ar). C NMR
3.49 (t, JZ6.6 Hz, 4H), 6.12 (t, JZ7.5 Hz, 2H), 7.095
(d, JZ7.8 Hz, 4H, Ar), 7.103 (d, JZ7.8 Hz, 4H, Ar), 7.21
(
CDCl , 75 MHz, TMS): d 30.4, 55.17, 55.21, 70.5, 113.3,
3
1
3
1
1
13.4, 113.5, 124.0, 128.38, 131.0, 132.2, 142.0, 158.4,
62.8. MS (%) m/z 550 (M , 0.55), 266 (66.78), 236 (100).
(d, JZ7.8 Hz, 4H, Ar), 7.31 (d, JZ7.8 Hz, 4H, Ar).
C
NMR (CDCl , 75 MHz, TMS): d 30.4, 70.2, 127.2, 128.3,
C
3
C
HRMS Calcd. for C H ONa (Maldi): 573.2615, Found:
3
5
128.4, 128.5, 131.2, 133.0, 133.1, 137.8, 140.6, 141.0. MS
(%) m/z 566 (M , 0.20), 305 (41.37), 275 (10.83), 125
2 30
C
73.2612 (MCNa ).
C
C
100). HRMS Calcd. for C H Cl O (Maldi): 567.0815,
(
Found: 567.0811 (MCH ).
32 27 4
C
4.2.4. Di{4,4-[1-phenyl-1-(4-methoxyphenyl)]-but-3-
en-1-yl} ether (2c). A colorless liquid, IR (CH Cl ): n
2
2
3
2
054, 3030, 3003, 2955, 2935, 2904, 2859, 2837, 2793, 2548,
K1
311, 2059, 1893, 1719, 1654, 1606, 1575, 1510, 1493 cm
4.2.9. Di[4,4-bis(4-fluorophenyl)-but-3-en-1-yl] ether
(2g). A colorless liquid, IR (CH Cl ): n 3045, 2955, 2863,
.
2
2
1
H NMR (CDCl , TMS, 300 MHz): d 2.31 (dt, JZ6.6,
2778, 2030, 1893, 1782, 1715, 1656, 1601, 1508, 1401,
1225 cm . H NMR (CDCl , TMS, 300 MHz): d 2.39 (dt,
3
K1 1
7
.5 Hz, 4H), 3.36–3.44 (m, 4H), 3.69 (s, 3H, CH O), 3.72
3
3
(
s, 3H, CH O), 5.96 (t, JZ7.5 Hz, 1H), 6.00 (t, JZ7.5 Hz,
JZ6.0, 6.9 Hz, 4H), 3.51 (t, JZ6.9 Hz, 4H), 6.07 (t, JZ
6.0 Hz, 2H), 6.92 (d, JZ6.9 Hz, 4H, Ar), 6.97 (d, JZ
6.9 Hz, 4H, Ar), 7.03 (d, JZ6.9 Hz, 4H, Ar), 7.07–7.18 (m,
3
1
Ar), 7.16–7.40 (m, 14H, Ar). C NMR (CDCl , 75 MHz,
TMS): d 30.4, 30.5, 55.16, 55.19, 70.46, 70.49, 113.4, 113.5,
H), 6.68 (d, JZ9.0 Hz, 2H, Ar), 6.80 (d, JZ8.4 Hz, 2H,
13
3
1
3
4H, Ar). C NMR (CDCl , 75 MHz, TMS): d 30.4, 70.3,
3
1
1
1
24.2, 125.7, 126.8, 126.9, 127.3, 128.0, 128.1, 128.3,
29.8, 131.0, 132.2, 135.3, 140.2, 142.5, 142.7, 143.0,
58.5, 158.7. MS (%) m/z 490 (M , 0.50), 267 (20.58), 236
115.0 (d, JC–FZ21.60 Hz), 115.2 (d, JC–FZ20.25 Hz),
126.3, 127.4 (d, JC–FZ7.28 Hz), 128.7 (d, JC–FZ7.58 Hz),
131.4 (d, JC–FZ7.28 Hz), 135.6 (d, JC–FZ3.68 Hz), 138.6
(d, JC–FZ3.08 Hz), 141.2, 161.9 (d, JC–FZ246.68 Hz),
C
C
(100). HRMS Calcd. for C H O Na (Maldi): 513.2429,
34 34 3
Found: 513.2400 (MCNa ).
C
C
162.1 (d, JC–FZ244.65 Hz). MS (%) m/z 502 (M , 0.15),
2
73 (27.26), 242 (60.00), 109 (100). HRMS Calcd. for
C
4
(
.2.5. Di[4,4-bis-(4-methylphenyl)-but-3-en-1-yl] ether
2d). A colorless liquid, IR (CH Cl ): n 3023, 2946, 2920,
C H F ONa (Maldi): 525.1805, Found: 525.1812
32 26 4
C
(MCNa ).
2
2
K1
2
865, 2733, 1900, 1719, 1656, 1608, 1511, 1449, 1278 cm
H NMR (CDCl , TMS, 300 MHz): d 2.30–2.46 (m, 16H),
.
1
4.2.10. Di[4,4-bis(fluorophenyl)-but-3-en-1-ol (3g).
A yellow liquid, IR (CH Cl ): n 3341, 3045, 2928, 2881,
3
3
.51 (t, JZ6.9 Hz, 4H), 6.61 (t, JZ7.2 Hz, 2H), 7.04–7.20
2
2

L.-X. Shao et al. / Tetrahedron 60 (2004) 11895–11901
11899
K1
1
1
893, 1719, 1602, 1508, 1409, 1225 cm
.
H NMR
(CDCl , TMS, 75 MHz): d 21.5, 29.2, 55.0, 69.8, 113.3,
3
(
3
(
6
1
1
2
CDCl , TMS, 300 MHz): d 2.31 (dt, JZ6.3, 7.2 Hz, 2H),
120.7, 127.0, 127.7, 128.1, 129.4, 130.6, 132.8, 139.4,
3
1
3
.66 (t, JZ6.3 Hz, 2H), 5.98 (t, JZ7.2 Hz, 1H), 6.85–7.13
144.2, 144.6, 158.6. (E- or Z-isomer) C NMR (CDCl3,
TMS, 75 MHz): d 21.5, 29.3, 55.0, 69.9, 113.5, 122.4,
127.1, 127.9, 128.1, 129.7, 131.3, 134.4, 142.2, 144.4,
1
3
m, 8H, Ar). C NMR (CDCl , 75 MHz, TMS): d 33.2,
3
2.5, 115.0 (d, JC–FZ21.15 Hz), 115.3 (d, JC–FZ42.9 Hz),
25.6, 128.8 (d, JC–FZ7.88 Hz), 131.4 (d, JC–FZ8.03 Hz),
C
144.6, 158.8. MS (%) m/z 408 (M , 4.59), 236 (72.85), 91
(100); HRMS Calcd. for C H O S (Maldi): 409.1488,
C
35.4 (d, JC–FZ3.75 Hz), 142.2, 162.0 (d, JC–F
Z
24
25 4
C
Found: 409.1468 (MCH ).
44.95 Hz), 162.1 (d, JC–FZ244.80 Hz). MS (%) m/z 260
C
(
M , 29.31), 229 (100). HRMS Calcd. for C H F O (EI):
16 14 2
2
60.1013, Found: 260.0989.
4.3.4. Toluene-4-sulfonic acid 4,4-di-p-tolyl-but-3-en-
-yl ester (4d). A white solid, Mp: 93–95 8C; IR (thin
film): n 2957, 2930, 1606, 1510, 1494, 1444, 1360, 1291,
1
4.3. The direct ring-opening of MCPs by toluene
p-sulfonic acid (TsOH)
K1
1
1247, 1176, 1097, 1033 cm ; H NMR (CDCl , TMS,
3
300 MHz): d 2.32 (s, 3H, CH ), 2.37 (s, 3H, CH ), 2.42 (s,
3 3
Under an argon atmosphere, MCPs 1 (0.50 mmol) and
toluene p-sulfonic acid (TsOH$H O) (0.55 mmol) were
3H, CH ), 2.43 (td, JZ6.6, 7.2 Hz, 2H), 4.06 (t, JZ6.6 Hz,
3
2H), 5.82 (t, JZ7.2 Hz, 1H), 6.96 (d, JZ8.1 Hz, 2H, Ar),
7.01–7.07 (m, 4H, Ar), 7.14 (d, JZ7.5 Hz, 2H, Ar), 7.28 (d,
2
added into a Schlenk tube with 1,2-dichloroethane (DCE)
(
1
3
2.0 mL). After gentle heating to make TsOH soluble in
JZ8.1 Hz, 2H, Ar), 7.76 (d, JZ8.1 Hz, 2H, Ar); C NMR
DCE, the reaction mixture was stirred at room temperature.
The solvent was removed under reduced pressure and then
the residue was purified by a flash column chromatography.
(CDCl , TMS, 75 MHz): d 21.0, 21.1, 21.5, 29.3, 69.9,
121.5, 127.0, 127.8, 128.7, 128.9, 129.4, 129.7, 130.1,
132.8, 136.3, 136.7, 136.9, 139.2, 144.6; MS (%) m/z: 406
3
C
M , 1), 346 (3.72), 234 (38.64), 219 (50.67), 59 (100);
(
Anal. Calcd. for C25
Found: C, 73.79; H, 6.46%.
4.3.1. Toluene-4-sulfonic acid 4,4-diphenyl-but-3-en-1-yl
ester (4a). A white solid, Mp: 84–86 8C; IR (thin film): n
H O S requires C, 73.86; H, 6.45;
26 3
K1 1
027, 1958, 1494, 1444, 1360, 1189, 1176, 1097 cm ; H
3
NMR (CDCl , TMS, 300 MHz): d 2.42–2.47 (m, 5H), 4.08
4.3.5. Toluene-4-sulfonic acid 4-(2-chlorophenyl)-4-
phenylbut-3-en-1-yl ester (4e). A white solid, Mp: 101–
103 8C; IR (thin film): n 2924, 1598, 1494, 1468, 1444,
3
(
t, JZ6.6 Hz, 2H), 5.90 (t, JZ7.2 Hz, 1H), 7.07–7.15 (m,
4
H, Ar), 7.23–7.35 (m, 8H, Ar), 7.76 (d, JZ8.1 Hz, 2H. Ar);
1
3
K1
1
C NMR (CDCl , TMS, 75 MHz): d 21.6, 29.4, 69.8,
22.7, 127.17, 127.23, 127.8, 128.1, 128.3, 129.6, 129.8,
33.0, 139.2, 141.8, 142.2, 144.7, 144.9; MS (%) m/z 377
1360, 1177, 1189, 1097, 1056, 1035 cm ; (Z-isomer) H
NMR (CDCl , TMS, 300 MHz): d 2.27 (dt, JZ6.3, 7.2 Hz,
3
1
1
3
2H), 2.38 (s, 3H, CH ), 4.06 (t, JZ6.3 Hz, 2H), 6.07 (t, JZ
3
C
(M K1, 0.84), 206 (100), 191 (25.36); Anal. Calcd. for
C H O S requires C, 72.99; H, 5.86; Found: C, 72.91; H,
7.2 Hz, 1H), 7.06–7.13 (m, 3H, Ar), 7.17–7.27 (m, 8H, Ar),
7.38–7.41 (m, 1H, Ar), 7.75 (d, JZ8.1 Hz, 2H, ArH);
2
3 22 3
1
(Z-isomer) C NMR (CDCl , TMS, 75 MHz): d 21.5, 29.3,
3
5
.86%.
3
69.3, 123.9, 126.1, 126.8, 127.1, 127.3, 127.72, 128.1,
128.8, 129.7, 131.26, 132.7, 137.7, 139.5, 141.7, 144.7;
4
.3.2. Toluene-4-sulfonic acid 4,4-bis(4-methoxyphenyl)
but-3-en-1-yl ester (4b). A colorless oil, IR (thin film): n
1
(E-isomer) H NMR (CDCl
JZ6.3, 7.2 Hz, 2H), 2.38 (s, 3H, CH
3
, TMS, 300 MHz): d 2.61 (dt,
3
2
1
3
956, 2837, 1606, 1575, 1541, 1463, 1359, 1290, 1247,
), 4.11 (t, JZ6.3 Hz,
K1
1
176, 1079, 1033 cm
;
00 MHz): d 2.40–2.47 (m, 5H), 3.79 (s, 3H, CH O), 3.83
H NMR (CDCl , TMS,
2H), 5.60 (t, JZ7.2 Hz, 1H), 7.06–7.13 (m, 3H, Ar), 7.17–
7.27 (m, 8H, Ar), 7.38–7.41 (m, 1H, Ar), 7.75 (d, JZ8.1 Hz,
3
3
1
2H, Ar); (E-isomer) C NMR (CDCl , TMS, 75 MHz): d
3
(
s, 3H, CH O), 4.06 (t, JZ6.6 Hz, 2H), 5.75 (t, JZ7.5 Hz,
3
3
1
H), 6.78 (d, JZ8.7 Hz, 2H, Ar), 6.87 (d, JZ8.7 Hz, 2H,
22.1, 28.8, 69.5, 126.4, 126.7, 127.70, 127.9, 128.5, 129.0,
129.58, 129.61, 131.34, 132.9, 133.3, 138.4, 139.5, 141.8,
142.6. MS (%) m/z 240 (M –TsOH) (100), 205 (89.98);
Anal. Calcd. for C23H21ClO S requires C, 66.90; H, 5.13;
3
Found: C, 66.80; H, 5.11%.
Ar), 6.99 (d, JZ9.0 Hz, 2H, Ar), 7.06 (d, JZ9.0 Hz, 2H,
Ar), 7.28 (d, JZ8.4 Hz, 2H, Ar), 7.76 (d, JZ8.4 Hz, 2H,
Ar); C NMR (CDCl , TMS, 75 MHz): d 21.6, 29.4, 55.21,
C
13
3
5
1
4
5.25, 70.0, 113.4, 113.6, 120.6, 127.9, 128.4, 129.8, 130.7,
31.7, 133.0, 135.0, 144.0, 144.6, 158.7, 158.9; MS (%) m/z
C
38 (M , 14.83), 266 (100), 253 (49.35), 235 (92.98);
4.3.6. Toluene-4-sulfonic acid 4,4-bis-(4-chlorophenyl)-
but-3-en-1-yl ester (4f). A white solid, Mp: 83–85 8C; IR
(thin film): n 2919, 2850, 1596, 1491, 1464, 1401, 1360,
C
HRMS Calcd. for C H O S (Maldi): 439.1572, Found:
2
4
5 27 5
C
39.1574 (MCH ).
K1
1
1
188, 1175, 1091, 1014 cm ; H NMR (CDCl , TMS,
3
4
.3.3. Toluene-4-sulfonic acid 4-(4-methoxyphenyl)-4-
300 MHz) d 2.40–2.45 (m, 5H) 4.10 (t, JZ6.6 Hz, 2H), 5.92
(t, JZ7.8 Hz, 1H), 7.01–7.08 (m, 4H, Ar), 7.21–7.36 (m,
phenylbut-3-en-1-yl ester (4c). A yellow oil, IR (thin
film): n 2957, 2837, 1606, 1510, 1360, 1291, 1248, 1176,
1
3
6H, Ar), 7.75 (d, JZ8.4 Hz, 2H, Ar); C NMR (CDCl ,
3
K1
097, 1033 cm ; (Z- or E-isomer) H NMR (CDCl , TMS,
1
1
3
TMS, 75 MHz) d 21.6, 29.4, 69.4, 124.0, 127.8, 128.3,
128.4, 128.7, 129.8, 130.9, 132.9, 133.37, 133.43, 137.2,
3
00 MHz) d 2.39–2.48 (m, 5H), 3.78 (s, 3H, CH O), 4.06 (t,
3
C
139.9, 142.7, 144.8; MS (%) m/z 274 (M –TsOH) (31.72),
JZ6.9 Hz, 2H), 5.81 (t, JZ6.9 Hz, 1H), 6.78 (d, JZ8.7 Hz,
H, Ar), 6.99–7.15 (m, 4H, Ar), 7.23–7.36 (m, 5H, Ar), 7.75
2
239 (100); Anal. Calcd. for C23H20Cl S requires C, 61.75;
2
H, 4.51; Found: C, 61.60; H, 4.67%.
1
(d, JZ8.1 Hz, 2H, Ar); (E- or Z-isomer) H NMR (CDCl ,
TMS, 300 MHz): d 2.39–2.48 (m, 5H), 3.83 (s, 3H, CH O),
3
3
4
8
.08 (t, JZ6.6 Hz, 2H), 5.83 (t, JZ6.9 Hz, 1H), 6.87 (d, JZ
.7 Hz, 2H, Ar), 6.99–7.15 (m, 4H, Ar), 7.23–7.36 (m, 5H,
4.3.7. Toluene-4-sulfonic acid 4,4-bis-(4-fluorophenyl)
but-3-en-1-yl ester (4g). A yellow oil, IR (thin film): n
1
3
K1 1
2926, 1601, 1508, 1361, 1223, 1189, 1177, 1096 cm ; H
Ar), 7.76 (d, JZ8.1 Hz, 2H, Ar); (Z- or E-isomer) C NMR

11900
L.-X. Shao et al. / Tetrahedron 60 (2004) 11895–11901
NMR (CDCl , TMS, 300 MHz): d 2.38–2.45 (m, 5H), 4.08
3
3. For recent reviews, please see: (a) Nakamura, I.; Yamamoto,
Y. Adv. Synth. Catal. 2002, 344, 111–129. (b) Brandi, A.;
Cicchi, S.; Cordero, F. M.; Goti, A. Chem. Rev. 2003, 103,
1213–1269.
(
t, JZ6.6 Hz, 2H), 5.85 (t, JZ7.2 Hz, 1H), 6.94 (dd, JZ9.0,
JHFZ9.0 Hz, 2H, Ar), 7.03–7.11 (m, 6H, Ar), 7.29 (d, JZ
1
3
8
.1 Hz, 2H, Ar), 7.76 (d, JZ8.1 Hz, 2H, Ar); C NMR
(
2
(
3
CDCl , TMS, 75 MHz): d 21.6, 29.3, 69.6, 115.0 (d, JC–F
1.5 Hz), 115.4 (d, JC–FZ21.5 Hz), 123.1, 127.8, 128.8
d, JC–FZ7.9 Hz), 129.8, 131.2, 133.0, 134.9 (d, JC–F
6.9 Hz), 137.9 (d, JC–FZ36.9 Hz), 143.0, 144.8, 163.1
Z
4. For some more recent related papers, please see: (a) de
Meijere, A.; Leonov, A.; Heiner, T.; Noltemeyer, M.; Bes,
M. T. Eur. J. Org. Chem. 2003, 472–478. (b) Belov, V. N.;
Savchenko, A. I.; Sokolov, V. V.; Straub, A.; de Meijere, A.
Eur. J. Org. Chem. 2003, 551–561. (c) de Meijere, A.;
Kuchuk, I. D.; Sokolov, V. V.; Labahn, T.; Rauch, K.;
Es-Sayed, M.; Kr a¨ mer, T. Eur. J. Org. Chem. 2003, 985–997.
(d) Huang, X.; Zhou, H.-W.; Chen, W.-L. J. Org. Chem. 2004,
3
Z
(
d, JC–FZ245.8 Hz), 162.3 (d, JC–FZ245.8 Hz); MS (%)
m/z 242 (M –TsOH) (100), 227 (19.43), 133 (30.78), 109
C
C
(
59.91); HRMS Calcd. for C H F O SNa (Maldi):
23 20 2 3
C
4
37.1008, Found: 437.0993 (MCNa ).
.3.8. Toluene-4-sulfonic acid 4-(4-ethoxyphenyl)pent-3-
en-1-yl ester (4h). A colorless oil, IR (thin film): n 2978,
69, 839–842. (e) Zhou, H.-W.; Huang, X.; Chen, W.-L. Synlett
2003, 2080–2082. (f) Huang, Z.; Zhou, H.-W. Org. Lett. 2002,
4, 4419–4422. (g) Zhou, H-W. ; Huang, X.; Chen, W.-L.
4
J. Org. Chem. 2004, 69, 5471–5472. (h) Huang, X.; Chen,
W.-L.; Zhou, H.-W. Synlett 2004, 329–331. (i) Siriwardana,
A. I.; Nakamura, I.; Yamamoto, Y. J. Org. Chem. 2004, 69,
3202–3204. (j) Oh, B. H.; Nakamura, I.; Saito, S.; Yamamoto,
Y. Heterocycles 2003, 61, 247–257.
2
1
3
2
5
4
928, 1607, 1511, 1478, 1360, 1245, 1188, 1177, 1117,
K1 1
097 cm ; (Z- or E-isomer) H NMR (CDCl , TMS,
3
00 MHz): d 1.37–1.44 (m, 3H, CH ), 1.95 (s, 3H, CH ),
3
3
.42 (s, 3H, CH ), 2.44–2.60 (m, 2H), 3.98–4.11 (m, 4H),
3
.45–5.53 (m, 1H), 6.80–6.86 (m, 2H, Ar), 7.20–7.31 (m,
H, Ar), 7.66–7.82 (m, 2H, Ar); (E- or Z-isomer) H NMR
1
5. For some related Lewis acid or Brønsted acid-mediated
reactions of MCPs, please see: (a) Peron, G. L. N.; Kittering-
ham, J.; Kilburn, J. D. Tetrahedron Lett. 1999, 40, 3045–3048.
(b) Miura, K.; Takasumi, M.; Hondo, T.; Saito, H.; Hosomi, A.
Tetrahedron Lett. 1997, 38, 4587–4590. (c) Peron, G. L. N.;
Kitteringham, J.; Kilburn, J. D. Tetrahedron Lett. 2000, 41,
1615–1618. (d) Patient, L.; Berry, M. B.; Kilburn, J. D.
Tetrahedron Lett. 2003, 44, 1015–1017. (e) Peron, G.; Norton,
D.; Kitteringham, J.; Kilburn, J. D. Tetrahedron Lett. 2001, 42,
347–349. (f) Nakamura, I.; Kamada, M.; Yamamoto, Y.
Tetrahedron Lett. 2004, 45, 2903–2906. (g) Patient, L.; Berry,
M. B.; Coles, S. J.; Hursthouse, M. B.; Kilburn, J. D. Chem.
Commun. 2003, 2552–2553.
(
CDCl , TMS, 300 MHz): d 1.37–1.44 (m, 3H, CH ), 1.50
3 3
(
s, 3H, CH ), 2.43 (s, 3H, CH ), 2.44–2.60 (m, 2H), 3.98–
3 3
4
7
.11 (m, 4H), 5.45–5.53 (m, 1H), 6.80–6.86 (m, 2H, Ar),
.20–7.31 (m, 4H, Ar), 7.66–7.82 (m, 2H, Ar); (Z- or
1
3
E-isomer) C NMR (CDCl , TMS, 75 MHz): d 21.6, 28.4,
3
6
1
3.25, 63.33, 69.7, 113.8, 114.0, 125.7, 127.7, 127.8,
29.69, 129.74, 135.3, 144.6, 157.3. (E- or Z-isomer)
1
3
C
NMR (CDCl , TMS, 75 MHz): d 21.6, 29.6, 63.3, 67.4,
3
7
1
1
3
0.1, 114.0, 119.3, 126.5, 127.8, 128.7, 129.7, 132.9, 137.6,
C
44.6, 158.0. MS (%) m/z 360 (M , 12.45), 188 (72.15),
C
73 (100); HRMS Calcd. for C H O S (Maldi):
2
0
26
4
C
61.1504, Found: 361.1468 (MCH ).
6
. For some of the Lewis acid or Brønsted acid-mediated
transformations of MCPs in our laboratory, please see: (a)
Shi, M.; Xu, B. Org. Lett. 2002, 4, 2145–2148. (b) Huang,
J.-W.; Shi, M. Tetrahedron 2004, 60, 2057–2062. (c) Shao,
L.-X.; Shi, M. Eur. J. Org. Chem. 2004, 426–430. (d) Chen,
Y.; Shi, M. J. Org. Chem. 2004, 69, 426–431. (e) Shao, L.-X.;
Shi, M. Adv. Synth. Catal. 2003, 345, 963–966. (f) Shi, M.;
Chen, Y. J. Fluoro. Chem. 2003, 122, 219–227. (g) Huang,
J.-W.; Shi, M. Tetrahedron Lett. 2003, 44, 9343–9347. (h) Shi,
M.; Chen, Y.; Xu, B.; Tang, J. Green Chem. 2003, 5, 85–88. (i)
Shi, M.; Xu, B. Tetrahedron Lett. 2003, 44, 3839–3842. (j) Xu,
B.; Shi, M. Org. Lett. 2003, 5, 1415–1418. (k) Shi, M.; Shao,
L.-X.; Xu, B. Org. Lett. 2003, 5, 579–582. (l) Shi, M.; Chen,
Y.; Xu, B.; Tang, J. Tetrahedron Lett. 2002, 43, 8019–8024.
Acknowledgements
We thank the State Key Project of Basic Research (Project
73) (No. G2000048007), Chinese Academy of Sciences
KGCX2-210-01), Shanghai Municipal Committee of
9
(
Science and Technology, and the National Natural Science
Foundation of China for financial support (203900502,
2
0025206 and 20272069).
Supplementary data
(
m) Shi, M.; Xu, B.; Huang, J.-W. Org. Lett. 2004, 6,
175–1178.
1
Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.tet.2004.09.
7
. Siriwardana, A. I.; Nakamura, I.; Yamamoto, Y. Tetrahedron
Lett. 2003, 44, 4547–4550.
1
05
8
. Ritter-type reaction product was obtained as a byproduct if the
3
reaction was carried out in CH CN (a) Ritter, J. J.; Minieri,
P. P. J. Am. Chem. Soc. 1948, 70, 4045–4048. (b) Ritter, J. J.;
Kalish, J. J. Am. Chem. Soc. 1948, 70, 4048–4050. (c) Reddy,
K. L. Tetrahedron Lett. 2003, 44, 1453–1455. (d) Krimen,
L. I.; Cota, D. J. Org. React. 1969, 17, 213–325. (e) Nair, V.;
Rajan, R.; Rath, N. P. Org. Lett. 2002, 4, 1575–1577.
References and notes
1
. Binger, P.; Schuchardt, U. Chem. Ber. 1981, 114, 3313–3324.
. For the synthesis of MCPs (a) Brandi, A.; Goti, A. Chem. Rev.
9. The rearrangement of cyclopropylmethyl cation has already
been studied extensively. It is reasonable that the substituents
on the double further stabilize the cation. Please seeCarey,
F. A.; Sundberg, R. J. Advanced Organic Chemistry, 5th ed.;
Plenum: New York, 1998; pp 221 and 419.
2
1998, 98, 589–635. (b) Carbocyclic Three-membered Ring
Compounds; de Meijere, A., Ed.; Houben-Weyl; Thieme:
Stuttgart, 1996; Vol. E17a-c.

L.-X. Shao et al. / Tetrahedron 60 (2004) 11895–11901
11901
1
0. Matrix-assisted laser desorption/ionization (MALDI) is a more
soft and sensitive ionization technique than others. Among the
chemical and physical ionization pathways suggested for
MALDI are gas-phase photoionization, ion-molecule
reactions, etc. The most widely accepted ion formation
mechanism involves gas-phase proton transfer or alkali
metal transfer in the expanding plume with photoionized
matrix molecules. The matrix will serve to minimize sample
damage from the laser pulse and inhibit the appearance of
molecular ionsde Hoffmann, E.; Stroobant, V. Mass
Spectrometry: Principles and Applications, 2nd ed.; Wiley:
Chichester, 2001; pp 28–32.