Reactions of vinylidenecyclopropanes with xanthydrol and xanthene

Article abstract of DOI:10.1016/j.tet.2010.07.004

Vinylidenecyclopropanes undergo ring-opening reactions with xanthydrol in the presence of BF₃·OEt₂ or with xanthene in the presence of DDQ at 0 °C in 1,2-dichloroethane to give the corresponding conjugate triene derivatives in moderate to good yields. Plausible reaction mechanisms have been discussed on the basis of previous literature and the control experiments. The further transformation of these trienes has been disclosed in DCE in the presence of BF₃·OEt₂ along with a plausible reaction mechanism. Vinylidenecyclopropanes undergo ring-opening reactions with xanthydrol in the presence of BF₃· OEt₂ or with xanthene in the presence of DDQ at 0 °C in 1,2-dichloroethane to give the corresponding conjugate triene derivatives in moderate to good yields and the further transformation of these trienes have been disclosed at the same time.

Full text of DOI:10.1016/j.tet.2010.07.004

Tetrahedron 66 (2010) 7104e7111
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Reactions of vinylidenecyclopropanes with xanthydrol and xanthene
*
Wei Yuan, Min Shi
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032 China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 21 May 2010
Received in revised form 2 July 2010
Accepted 2 July 2010
Available online 24 July 2010
Vinylidenecyclopropanes undergo ring-opening reactions with xanthydrol in the presence of BF3$OEt2 or
with xanthene in the presence of DDQ at 0 ꢀC in 1,2-dichloroethane to give the corresponding conjugate
triene derivatives in moderate to good yields. Plausible reaction mechanisms have been discussed on the
basis of previous literature and the control experiments. The further transformation of these trienes has
been disclosed in DCE in the presence of BF3$OEt2 along with a plausible reaction mechanism.
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
Vinylidenecyclopropanes
Xanthydrol
Xanthene
DDQ
Lewis acid
1. Introduction
VDCPs 1 with a variety of nucleophiles, such as alcohols and aro-
matic amines as well as other reactants under mild conditions to
Vinylidenecyclopropanes (VDCPs) 1, which have strained
cyclopropyl group connected with an allene moiety and yet are
thermally stable and reactive substances in organic chemistry, are
versatile intermediates in organic synthesis.1 Thus far, many novel
transformations of these interesting highly strained small mole-
cules have been disclosed by many organic chemists. For example,
we and others have recently been investigating the Lewis acid/
transition metal-mediated/catalyzed ring-opening reactions of
produce a variety of interesting compounds.2,3 More recently, we
have found a novel cationic 1,4-aryl migration process in the
BF3$Et2O-catalyzed intermolecular reactions of vinylidenecyclo-
propanes 1 with bis(p-alkoxyphenyl)methanols, such as bis(p-
methoxyphenyl)methanol in 1,2-dichloroethane (DCE) to give the
corresponding indene derivatives in good yields under mild con-
ditions (Scheme 1).4 It is conceivable that if using similarly elec-
tron-rich xanthydrol 2a as the electrophile in this reaction, 1,4-aryl
Ar1
OH
Ar2
Ar1
BF3 . OEt2
Ar1'
.
+
Ar1'
MeO
1
DCE, rt
Ar2
OMe
Ar2 = p-MeOC6H4
1,4-aryl migration
OH
Ar1
.
+
?
Ar1'
O
1
2a
Scheme 1. BF3$Et2O-catalyzed Intermolecular Reactions of Vinylidenecyclopropanes 1 with Bis(p-methoxyphenyl)methanol.
migration will not be able to take place. Therefore, it is quite
interesting to examine what happens in this type of BF3$Et2O-cat-
alyzed reaction. In this paper, we wish to report the full details
of ring-opening reactions of vinylidenecyclopropanes with
* Corresponding author. E-mail address: mshi@mail.sioc.ac.cn (M. Shi).
0040-4020/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.07.004

W. Yuan, M. Shi / Tetrahedron 66 (2010) 7104e7111
7105
Table 2
xanthydrol 2a in the presence of BF3$OEt2 and its derivative xan-
Reactions of VDCP 1a with xanthene 2b in the presence of DDQ
thene 2b in the presence of 2,3-dichloro-5,6-dicyano-p-benzoqui-
none (DDQ) as well as the further transformation of the obtained
ring-opening products.
Ph
Ph
Ph
Ph
DDQ (x equiv)
solvent, temp
.
1a
+
O
2. Results and discussion
2b
(2.0 equiv)
O
3a
Initial examination in the BF3$Et2O (10 mol %)-catalyzed reaction
of diphenylvinylidenecyclopropane 1a (1.0 equiv) with 2a (2.0 equiv)
revealed that the ring-opening reaction took place efficiently to give
a conjugate triene product 3a in good yield within 20 min rather
than the 1,4-aryl migration product. The results of these experiments
on the examination of the substrate scope are summarized in Table 1.
As can be seen from Table 1, all of the reactions proceeded smoothly
to give the corresponding trienes 3 in moderate to good yields. As for
electron-neutral phenyl groups substituted VDCPs 1a and 1c as well
as electron-rich aromatic groups substituted VDCPs 1g, 1h, and 1i,
Entrya
Solvent
x
Time (min)
Temp (ꢀC)
Yieldb (%)
3a
1
2
3
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCM
THF
CH3CN
Et2O
Toluene
DMF
1.5
1.5
2.0
2.5
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
5
30
30
30
30
30
30
30
30
30
30
30
30
30
rt
rt
rt
rt
rt
30
40
0
0
0
0
0
44
48
70
70
75
59
68
85
81
31
80
57
11
Trace
4
5c
6
7
8
9
10
11
12
13
14
Table 1
BF3$OEt2-catalyzed Ring-opening Reactions of Vinylidenecyclopropanes with Xan-
thydrol 2a in DCE
Ar1
OH
0
0
Ar2
Ar1
Ar2
BF3.OEt2 (10 mol%)
DCE, 0 o
.
1
+
C
Bold values signify the best reaction conditions.
O
a
VDCP 1a (0.20 mmol), 2a (2.0 equiv) and DDQ were dissolved in 2 mL of solvent
under argon atmosphere, and the reaction mixtures were stirred for several minutes
at certain temperatures.
2a (2.0 equiv)
O
3
b
Isolated yields.
c
Compound 2a and DDQ were dissolved in solvent at rt under argon atmosphere.
Entrya
Ar1/Ar2
Yieldb (%)
After 2.0 min, VDCP 1a was added into the flask.
3
optimize the reaction conditions and the results of these experiments
are summarized in Table 2. We found that increasing the employed
amount of DDQ to 2.0 equiv or 2.5 equiv could improve the yields of
3a to 70% or 75% at room temperature and raising the reaction tem-
perature to 30 ꢀC or 40 ꢀC did not significantly affect the yields of 3a
(Table 2, entries 3e5 and 6e7). Performing the reaction at 0 ꢀC
afforded 3a in 85% yield in DCE in the presence of 2.0 equiv of 2a
1
2
3
4
5
6
7
8
9
C6H5/C6H5, 1a
p-FC6H4/p-FC6H4, 1b
p-ClC6H4/C6H5, 1c
p-ClC6H4/p-ClC6H4, 1d
p-BrC6H4/p-BrC6H4, 1e
C6H5/o-CH3C6H4, 1f
p-CH3C6H4/C6H5, 1g
p-CH3C6H4/p-CH3C6H4, 1h
p-MeOC6H4/p-MeOC6H4, 1i
3a, 83
3b, 76
3c, 65c
3d, 42
3e, 41
3f, 44d
3g, 88e
3h, 94
3i, 86
a
Table 3
All reactions were carried out using 1 (0.20 mmol), 2a (0.4 mmol, 2.0 equiv), and
BF3$Et2O (10 mol %) in DCE at rt within 20 min unless otherwise specified.
Reactions of various VDCPs 1 with xanthene 2b in the presence of DDQ
b
Isolated yields.
Ar1
c
E- or Z-isomeric mixture (ratio¼1.2:1).
d
E-or Z-isomeric mixture (ratio¼4:1).
Ar1
Ar2
Ar2
e
DDQ
(2.0 equiv)
DCE, 0 oC
E- or Z-isomeric mixture (ratio¼1.2:1).
.
1
+
O
the corresponding trienes 3a, 3c, 3g, 3h, and 3i were obtained in
65e94% yields (Table 1, entries 1, 3, and 7e9). Only in the case of
VDCP 1f bearing one ortho-methyl group on the benzene ring, the
corresponding triene 3f was obtained in 44% yield, presumably due
to the steric hindrance (Table 1, entry 6). In the cases of VDCPs 1d and
1e in which the aromatic rings bearing electron-withdrawing
groups, the corresponding trienes 3d and 3e were formed in mod-
erate yields (Table 1, entries 4 and 5). For unsymmetrical diaryl-
substituted VDCPs 1c, 1f, and 1g, the corresponding trienes 3c, 3f,
and 3g were attained as E- and Z-isomeric mixtures with different
ratios (Table 1, entries 3, 6, and 7).
ThisresultalsostimulatedustoinvestigatethereactionofVDCPs 1
with xanthene 2b because it has been reported that the similar cat-
ionic intermediate as that in the reaction of 2awith BF3$OEt2 could be
generated if using 2b in the presence of 2,3-dichloro-5,6-dicyano-p-
benzoquinone (DDQ) under mild conditions.5 The initial examination
was carried out in DCE using 1a (1.0 equiv) and 2b (2.0 equiv) as the
substrates in the presence of DDQ (1.5 equiv) to verify the reaction
outcome. It was found that the corresponding triene 3a was indeed
formed in 44% yield at room temperature (20 ꢀC) within 5 min and in
48%yieldafter20 min(Table 2, entries1and2). Next, weattemptedto
2b (2.0 equiv)
O
3
Entrya
Ar1/Ar2
Yieldb (%)
3
1
2
3
4
5
6
7
8
9
C6H5/C6H5, 1a
3a, 85
3b, 74
3c, 71c
3d, 80
3e, 85
3f, 31d
3g, 65e
3h, 82
3i, 58
p-FC6H4/p-FC6H4, 1b
p-ClC6H4/C6H5, 1c
p-ClC6H4/p-ClC6H4, 1d
p-BrC6H4/p-BrC6H4, 1e
C6H5/o-CH3C6H4, 1f
p-CH3C6H4/C6H5, 1g
p-CH3C6H4/p-CH3C6H4, 1h
p-MeOC6H4/p-MeOC6H4, 1i
p-FC6H4/C6H5, 1j
10
3j, 92f
a
All reactions were carried out using 1 (0.20 mmol), 2a (0.40 mmol, 2.0 equiv),
and BF3$Et2O (10 mol %) in DCE at room temperature within 20 min unless other-
wise specified.
b
Isolated yields.
c
E- or Z-isomeric mixture (ratio¼1.2:1).
d
E- or Z-isomeric mixture (ratio¼4:1).
e
E- or Z-isomeric mixture (ratio¼1.2:1).
f
E- or Z-isomeric mixture (ratio¼1:1).

7106
W. Yuan, M. Shi / Tetrahedron 66 (2010) 7104e7111
DDQ (2.0 equiv)
DCE, 0 oC
expected product
1a
+
H3CO
OCH3
Ph
CN
2c
DDQ (2.0 equiv)
DCE, 0 o
C
CN
3a' (29%)
Scheme 2. The reaction of 1a with 2c in the Presence of DDQ.
within 30 min, which served as the best reaction conditions for this
transformation (Table 2, entry 8). The examination of solvent effects
revealed that dichloromethane (DCM) and acetonitrile (CH3CN) are
the suitable solvents for this reaction, giving 3a in 81% and 80% yield,
respectively (Table 2, entries 9e14).
Under these optimal reaction conditions, we next carried out this
interesting ring-opening reaction of a variety of VDCPs 1 with 2b to
probe the substrate scope and the results of these experiments are
outlined in Table 3. As can be seen from Table 3, the reactions pro-
ceeded smoothly to give the corresponding trienes 3 in moderate to
good yields. As for VDCP 1f, the corresponding product 3f was attained
Figure 1. ORTEP drawing of 3a0.
Ph
Ph
.
OH
BF3 . OEt2
1a
Ph
Ph
R
O
A
O
2a
B1
H
Ph
Ph
Ph
Ph
R
R
B2
3a
CN
O
H
H
O
CN
O
Cl
Cl
CN
CN
+
+
Cl
O
O
Cl
O
C
2b
DDQ
CN
CN
HO
Cl
CN
HO
Cl
CN
O
OH
Cl
Ph
.
1a
Cl
O
Ph
D
H
Ph
Ph
Ph
Ph
Ph
Ph
R
R
R
B2
B1
3a
R =
O
Scheme 3. Plausible reaction mechanisms.

W. Yuan, M. Shi / Tetrahedron 66 (2010) 7104e7111
7107
in31% yieldsimilarly duetothestericeffect(Table 3, entry6). Forthese
unsymmetrical diaryl-substituted VDCPs 1d, 1f, 1g, and 1j, the corre-
sponding trienes 1d,1f,1g, and 1j were obtained similarly as E- and Z-
isomeric mixtures with different ratios (Table 3, entries 3, 6, and 7).
The control experiment indicated that using bis(4-methoxy-
phenyl)methane 2c to replace 2b in this reaction, none of the
expected product was produced under the standard conditions,
instead, another cycloaddition product 3a0 of 1a with DDQ was
formed in 29% yield, suggesting that the structure and electronic
property of xanthene 2b played an important role in this reaction
(Scheme 2). The structure of 3a0 was unambiguously determined by
X-ray diffraction. Its ORTEP drawing is shown in Figure 1 and its CIF
data are presented in the Supplementary data.6 A plausible reaction
mechanism has been shown in the reference section7 on the basis
of the previous literature.8
transformation is good for a variety of compounds 3 under the
standard conditions using BF3$OEt2 (10 mol %) as the catalyst to
give the products 4 in moderate to good yields (Table 4). As for
substrates 3b, 3d, and 3e having electron-withdrawing groups on
their benzene rings, the corresponding products 4b, 4d, and 4e
were obtained in moderate yields (Table 4, entries 4, 6, and 7) and
others were obtained in good yields (Table 4, entries 5 and 8e10). In
the cases of unsymmetrical substrates 3c and 3g (R1 and R2 are not
identical), the products 4c and 4g were formed as isomeric mix-
tures in good yields (Table 4, entries 5 and 8, see the Supplementary
data for the detail). The structure of 4i has been ambiguously de-
termined by X-ray diffraction (Fig. 2) and its CIF data are presented
in the Supplementary data.9
The reaction mechanisms of VDCP 1 with 2a catalyzed by
BF3$OEt2 and 1 with 2b in the presence of DDQ are outlined in
Scheme 3 using VDCP 1a as a model. Initially, the cationic in-
termediate A is formed by the treatment of 2a with BF3$OEt2,2,4
which reacts with 1a to give the corresponding resonance-stabi-
lized cationic intermediates B1 and B2 (allylic cation) (Scheme 3).
Deprotonation of B2 affords triene 3a. On the other hand, if using
2b as the substrate, the charge-transfer complex C (radical ionic
pair) is firstly formed with DDQ via a single electron-transfer,5
which undergoes H transfer to give intermediate D (ionic pair).
The reaction of cationic xanthene intermediate with 1a produces
the similar resonance-stabilized cationic intermediates B1 and B21,
which gives product 3a via deprotonation (Scheme 3).
The further transformation of 3 has been examined in the
presence of several catalysts, such as AlCl3, Brønsted acid tri-
fluoromethanesulfonic acid CF3SO3H (TfOH), and BF3$OEt2 (10 mol
%) in DCE. We found that AlCl3 (10 mol %) did not promote the
further transformation of 3, but using TfOH or BF3$OEt2 (10 mol %)
as the catalyst gave a novel spiro-alkane 4a in 97% yield at 70 ꢀC if
using 3a as substrate (Table 4, entries 1e3). The generality of this
Figure 2. ORTEP drawing of 4i.
Table 4
Further transformation of 3 and the formation of spiro-alkanes 4
R1
R1
A plausible reaction mechanism for the formation of spiro-
alkane 4 is outlined in Scheme 4 using 3a as a model. BF3$OEt2 may
play as a Brønsted acid type catalyst E in the presence of trace of
water,10 which reacts with 3a gives the corresponding resonance-
stabilized cationic intermediates F1 and F2 (allylic cation).
Intermediate F1 affords the corresponding resonance-stabilized
R =
catalyst (10 mol%)
DCE, 70 o
R
R2
R2
C
cationic intermediates G1 and G2 (allylic cation) through 1,3-
s
O
O
hydrogen shift and then, intermediate G1 undergoes intramole-
cular FriedeleCrafts reaction to afford spiro-alkyl intermediate H,
which gives spiro-alkane 4a via a protonation and a deprotonation
through intermediate I (Scheme 4).
3
4
Entrya
Catalyst
R1/R2
Yieldb (%)
3
1
2
3
4
5
6
7
8
9
AlCl3
HOTf
H/H, 3a
H/H, 3a
H/H, 3a
F/F, 3b
Cl/H, 3c
Cl/Cl, 3d
Br/Br, 3e
CH3/H, 3g
CH3/CH3, 3h
nr
4a, 97
4a, 97
4b, 56
4c, 97c
4d, 62
4 e, 50
4g, 89d
4h, 92
4i, 88
3. Conclusion
BF3$OEt2
BF3$OEt2
BF3$OEt2
BF3$OEt2
BF3$OEt2
BF3$OEt2
BF3$OEt2
BF3$OEt2
In summary, we have disclosed the reactions of vinyl-
idenecyclopropanes (VDCPs) 1 with xanthydrol 2a in the presence
of BF3$OEt2 (10 mol %) or 1 with xanthene in the presence of DDQ
(2.0 equiv) at 0 ꢀC in 1,2-dichloroethane to give the corresponding
conjugate triene derivatives 3 in moderate to good yields. Plausible
reaction mechanisms have been discussed on the basis of previous
literature and the control experiments. An interesting trans-
formation of these conjugate trienes has been disclosed in the
presence of BF3$OEt2 (10 mol %) at 70 ꢀC, affording a series of novel
spiro-alkanes 4 in moderate to good yields. Efforts are in progress to
further elucidate the mechanistic details of this reaction and to
determine its scope and limitations.
10
CH3O/CH3O, 3i
a
Compound 1 (0.20 mmol) was dissolved in DCE (2.0 mL) in a flask under argon,
then, x (10 mol %) was added into the flask. The reaction was carried out at 70 ꢀC
within 3 h.
b
Isolated yields.
c
The E/Z isomeric mixtures were used in this reaction and the ratio of the product
mixtures is 1.2:1.
d
The E/Z isomeric mixtures were used in this reaction and the ratio of the product
mixtures is 1.2:1.

7108
W. Yuan, M. Shi / Tetrahedron 66 (2010) 7104e7111
O
3a
+
trace of water
BF3.OEt2
HBF3.OEt2
H
H
H
OH-
E
O
F1
O
F2
[1, 3] H shift
Intramolecular
Friedel-Craf s
t
+ H+
reaction
- H+
O
O
O
G2
O
G1
I
H
- H+
O
4a
Scheme 4. A Plausible Reaction mechanism for the formation of 4a.
4. Experimental procedures
4.1. General methods
DDQ (0.40 mmol) was added. The reaction was stirred at 0 ꢀC for
20 min. Then, the solvent was removed under reduced pressure and
the residue was purified by a flash column chromatography (SiO2) to
give the corresponding products 3 in moderate to good yields.
1H and 13C NMR spectra were recorded at the 300 and 75 MHz or
the 400 and 100 MHz, respectively. Mass and HRMS spectra were
recorded by EI or ESI method. Organic solvents used were dried by
standard methods when necessary. Satisfactory CHN microanalyses
were obtained with an analyzer. Commercially obtained reagents
were used without further purification. All these reactions were
monitored by TLC with silica gel coated plates. Flash column chro-
matography was carried out using silica gel at increased pressure.
4.3.1. Compound 3a. Awhite solid, mp: 154e155 ꢀC.1H NMR (CDCl3,
300 MHz, TMS) d 1.23 (s, 3H, CH3),1.29 (s, 3H, CH3),1.44 (s, 3H, CH3),
4.19 (s,1H), 4.70 (s,1H), 5.57 (s,1H), 6.81e6.96 (m, 4H, Ar), 7.08e7.23
(m, 7H, Ar), 7.27e7.38 (m, 7H, Ar). 13C NMR (CDCl3, 75 MHz, TMS)
d
21.9, 22.9, 23.3, 40.2, 115.9, 116.0, 118.8, 121.9, 122.0, 122.2, 123.2,
126.2,126.7,127.2,127.6,127.7,128.6,129.0,129.4,129.5,130.2,132.7,
135.1, 140.5, 143.1, 143.4, 143.72, 143.75, 150.9, 151.4. IR (CH2Cl2)
n
3075, 2925, 2853,1738,1600,1574,1481,1450,1367,1322,1258,1216,
1096, 905, 751 cmꢁ1. MS (ESI) m/e 455.2 (Mþþ1). HRMS (MALDI)
calcd for C34H31O: 455.2377, found: 455.2369.
4.2. General procedure for the reactions of VDCPs 1 with
xanthydrol 2a in the presence of BF3$OEt2 (10 mol %)
4.3.2. Compound 3b. A white solid, mp: 160e162 ꢀC. 1H NMR
Under argon atmosphere, vinylidenecyclopropanes (VDCPs) 1
(0.20 mmol), and xanthydrol 2a (0.40 mmol) were dissolved in DCE
(2.0 mL) in a Schlenk tube at 0 ꢀC, then, BF3$OEt2 (10 mol %) was
inserted into the tube. The reaction mixture was stirred at 0 ꢀC until
the reaction completed. Then, the solvent was removed under re-
duced pressure and the residue was purified by a flash column
chromatography (SiO2) to give the corresponding products 3 in
moderate to good yields.
(CDCl3, 300 MHz, TMS)
d 1.22 (s, 3H, CH3), 1.34 (s, 3H, CH3), 1.53
(s, 3H, CH3), 4.32 (s, 1H), 4.82 (s, 1H), 5.50 (s, 1H), 6.80e7.02 (m,
8H, Ar), 7.07e7.28 (m, 8H, Ar). 13C NMR (CDCl3, 75 MHz, TMS)
d
21.9, 23.21, 23.23, 39.9, 114.2 (d, JCeF¼21.2 Hz), 115.5 (d,
JCeF¼21.2 Hz), 115.9, 116.2, 119.1, 122.0, 122.09, 122.11, 123.1, 127.7,
127.8, 128.6, 129.1, 130.9 (d, JCeF¼8.0 Hz), 131.5 (d, JCeF¼7.4 Hz),
132.8, 135.4, 139.2 (d, JCeF¼3.7 Hz), 139.6 (d, JCeF¼3.5 Hz), 141.4,
141.7, 143.0, 150.6, 151.2, 161.3 (d, JCeF¼244.8 Hz), 161.6 (d,
JCeF¼245.1 Hz). IR (CH2Cl2)
n 3075, 3040, 2923, 2854, 1715, 1601,
4.3. General procedure for the reactions of VDCPs 1 with
xanthene 2b in the presence of DDQ
1577, 1504, 1481, 1451, 1367, 1323, 1258, 1223, 1096, 905,
752 cmꢁ1. MS (ESI) m/e 491.2 (Mþþ1). HRMS (MALDI) calcd for
C34H29OF2: 491.2196, found: 491.2181.
Under argon atmosphere, vinylidenecyclopropanes 1 (0.20 mmol)
and xanthene 2b (0.40 mmol) were added into a Schlenk tube, and
then the solventofDCE (2.0 mL) wasadded. The reaction mixturewas
stirred at 0 ꢀC for a while until the solid substrates dissolved, then
4.3.3. Compound 3c. (A E/Z mixture, ratio¼1.2:1.0). A white solid,
mp: 162e164 ꢀC. 1H NMR (CDCl3, 400 MHz, TMS)
d 1.21 (s, 1.65H,

W. Yuan, M. Shi / Tetrahedron 66 (2010) 7104e7111
7109
CH3), 1.24 (s, 1.35H, CH3), 1.31 (s, 3H, CH3), 1.43 (s, 1.65H, CH3), 1.53
(s, 1.35H, CH3), 4.21 (s, 0.55H), 4.31 (s, 0.45H), 4.72 (s, 0.55H), 4.80
(s, 0.45H), 5.49 (s, 0.45H), 5.55 (s, 0.55H), 6.81e6.96 (m, 4H, Ar),
132.6, 135.0, 135.1, 135.7, 136.4, 139.8, 140.1, 140.77, 140.83, 143.05,
143.15, 143.3, 143.4, 143.88, 143.94, 150.8, 151.4. IR (CH2Cl2) 3075,
3022, 2921, 2853, 1715, 1601, 1574, 1481, 1450, 1367, 1322, 1258,
1217, 1096, 905, 751 cmꢁ1. MS (%) m/e 468 (Mþ, 21.60), 441 (1.18),
425 (2.07), 371 (4.31), 287 (13.72), 272 (3.57), 257 (4.38), 181
(100.00). HRMS (EI) calcd for C35H32O: 468.2453, found: 468.2449.
n
7.10e7.35 (m, 13H, Ar). 13C NMR (CDCl3, 100 MHz, TMS)
d 21.91,
21.94, 22.9, 23.3, 40.0, 40.2, 115.90, 115.92, 116.1, 116.2, 118.9, 119.1,
121.96, 122.00, 122.02, 122.06, 122.09, 122.2, 123.0, 123.1, 126.4,
127.0, 127.3, 127.5, 127.67, 127.75, 127.8, 128.63, 128.64, 128.7, 128.9,
129.2, 129.3, 129.4, 130.7, 131.4, 132.0, 132.6, 132.9, 133.0, 135.0,
135.4,141.3,141.5,142.0,142.1,142.2,142.3,142.7,143.2,143.4,150.6,
4.3.8. Compound 3h. A white solid, mp: 154e156 ꢀC. 1H NMR
(CDCl3, 400 MHz, TMS)
d 1.23 (s, 3H, CH3), 1.29 (s, 3H, CH3), 1.40 (s,
150.8, 151.3, 151.4. IR (CH2Cl2)
n
3077, 2969, 2906, 2852, 1715, 1601,
3H, CH3), 2.24 (s, 3H, CH3), 2.31 (s, 3H, CH3), 4.13 (s, 1H), 4.66 (s, 1H),
1574, 1481, 1450, 1367, 1322, 1257, 1217, 1092, 904, 749 cmꢁ1. MS (%)
m/e 488 (Mþ, 4.94), 445 (0.65), 393 (0.51), 335 (0.53), 215 (1.57),181
(100.00), 165 (1.91), 152 (4.13). HRMS (EI) calcd for C34H29OCl:
488.1907, found: 488.1908.
5.59 (s, 1H), 6.80e6.97 (m, 6H, Ar), 7.07e7.18 (m, 6H, Ar), 7.26e7.36
(m, 4H, Ar). 13C NMR (CDCl3, 100 MHz, TMS)
d 21.1, 21.2, 21.8, 22.9,
23.2, 40.3, 115.8, 116.0, 118.6, 121.8, 121.9, 122.4, 123.3, 127.5, 127.6,
127.9, 129.1, 129.3, 129.5, 130.0, 132.4, 135.1, 135.6, 136.3, 139.6,
141.0, 141.1, 143.1, 143.2, 150.9, 151.5. IR (CH2Cl2) n 3075, 3021, 2969,
4.3.4. Compound 3d. A white solid, mp: 174e176 ꢀC. 1H NMR
2921, 2854,1738,1717,1601,1575,1481,1450,1366,1323,1258,1217,
1095, 905, 751 cmꢁ1. MS (ESI) m/e 483.1 (Mþþ1). HRMS (MALDI)
calcd for C36H35O: 483.2695, found: 483.2682.
(CDCl3, 300 MHz, TMS)
3H, CH3), 4.33 (s, 1H), 4.82 (s, 1H), 5.47 (s, 1H), 6.79e6.97 (m, 4H,
Ar), 7.07e7.28 (m, 12H, Ar). 13C NMR (CDCl3, 75 MHz, TMS)
22.0,
d 1.22 (s, 3H, CH3), 1.34 (s, 3H, CH3), 1.52 (s,
d
23.2, 40.0, 115.9, 116.3, 119.2, 121.9, 122.06, 122.13, 122.8, 127.6,
127.8, 127.9, 128.5, 128.8, 129.1, 130.6, 131.3, 132.2, 132.8, 133.2,
4.3.9. Compound 3i. A colorless oil. 1H NMR (CDCl3, 400 MHz, TMS)
d
1.24 (s, 3H, CH3), 1.31 (s, 3H, CH3), 1.43 (s, 3H, CH3), 3.72 (s, 3H,
135.3, 141.1, 141.5, 141.8, 142.3, 142.8, 150.6, 151.2. IR (CH2Cl2)
n
3076,
OCH3), 3.77 (s, 3H, OCH3), 4.15 (s, 1H), 4.69 (s, 1H), 5.60 (s, 1H), 6.68
3039, 2924, 2853, 1902, 1715, 1601, 1575, 1481, 1451, 1367, 1322,
1257, 1218, 1091, 905, 751 cmꢁ1. MS (ESI) m/e 523.1 (Mþþ1). HRMS
(MALDI) calcd for C34H29OCl2: 523.1583, found: 523.1590.
(2H, d, J¼8.8 Hz, Ar), 6.86e6.88 (m, 6H, Ar), 7.14e7.16 (m, 4H, Ar),
7.29e7.34 (m, 4H, Ar). 13C NMR (CDCl3, 100 MHz, TMS)
d 21.8, 22.9,
23.1, 40.1, 55.0, 55.2, 112.5, 114.0, 115.8, 115.9, 118.7, 121.8, 121.9,
122.4, 123.4, 127.47, 127.54, 128.9, 129.4, 130.6, 131.2, 132.2, 135.3,
136.3, 136.6, 139.3, 142.7, 143.2, 150.7, 151.4, 157.8, 158.3. IR (CH2Cl2)
4.3.5. Compound 3e. Awhitesolid, mp: 180e182 ꢀC.1HNMR (CDCl3,
300 MHz, TMS)
d
1.22 (s, 3H, CH3),1.34 (s, 3H, CH3),1.52 (s, 3H, CH3),
n 3033, 2998, 2906, 2835, 1715, 1604, 1575, 1508, 1481, 1450, 1366,
4.33 (s,1H), 4.83 (s,1H), 5.46 (s,1H), 6.80e6.96 (m, 4H, Ar), 7.03e7.28
1322, 1246, 1173, 1096, 904, 752 cmꢁ1. MS (ESI) m/e 515.2 (Mþþ1).
(m, 10H, Ar), 7.40e7.43 (m, 2H, Ar). 13C NMR (CDCl3, 75 MHz, TMS)
HRMS (MALDI) calcd for C36H35O3: 515.2583, found: 515.2581.
d
22.0, 23.3, 29.7, 40.0, 116.0, 116.3, 119.2, 120.5, 121.0, 121.9, 122.07,
122.14,122.8,127.8,127.9,128.5,129.1,130.5,130.9,131.6,131.7,133.2,
135.3, 141.1,141.9, 142.2, 142.3, 142.8,150.6,151.2. IR (CH2Cl2) 3076,
4.3.10. Compound 3j. (A E/Z mixture, ratio¼1:1). A white solid,
n
mp: 140e141 ꢀC. 1H NMR (CDCl3, 300 MHz, TMS)
d 1.22 (s, 1.5H,
2964, 2923, 2852,1715,1601,1574,1482,1450,1362,1322,1258,1218,
1010, 905, 750 cmꢁ1. MS (ESI) m/e 613.0 (Mþþ1). HRMS (MALDI)
calcd for C34H29OBr2: 611.0581, found: 611.0580.
CH3), 1.23 (s, 1.5H, CH3), 1.30 (s, 1.5H, CH3), 1.32 (s, 1.5H, CH3), 1.43
(s, 1.5H, CH3), 1.54 (s, 1.5H, CH3), 4.20 (s, 0.5H), 4.31 (s, 0.5H), 4.71
(s, 0.5H), 4.80 (s, 0.5H), 5.51 (s, 0.5H), 5.56 (s, 0.5H), 6.80e7.01 (m,
6H, Ar), 7.09e7.21 (m, 7H, Ar), 7.24e7.37 (m, 4H, Ar). 13C NMR
4.3.6. Compound 3f. (A E/Z mixture, ratio¼4:1). A white solid, mp:
(CDCl3, 75 MHz, TMS) d 21.9, 22.0, 22.9, 23.3, 40.0, 40.2, 114.2 (d,
130e132 ꢀC.1H NMR (CDCl3, 300 MHz, TMS)
d
1.09 (s, 2.4H, CH3),1.17
JCeF¼21.2 Hz), 115.4 (d, JCeF¼21.2 Hz), 115.87, 115.92, 116.1, 116.2,
118.9, 119.1, 121.97, 122.01, 122.05, 122.1, 122.3, 123.1, 123.2, 126.3,
126.9, 127.3, 127.66, 127.74, 127.8, 128.66, 128.71, 128.9, 129.2,
129.3, 129.4, 130.1, 131.0 (d, JCeF¼7.7 Hz), 131.6 (d, JCeF¼7.7 Hz),
132.8, 135.0, 135.5, 139.5 (d, JCeF¼5.6 Hz), 139.7 (d, JCeF¼2.9 Hz),
140.8, 141.4, 142.2, 142.6, 142.8, 143.3, 143.5, 143.7, 150.7, 150.9,
151.3, 151.4, 161.2 (d, JCeF¼244.7 Hz), 161.6 (d, JCeF¼245.2 Hz). IR
(s, 0.6H, CH3), 1.34 (s, 2.4H, CH3), 1.53 (s, 0.6H, CH3), 1.54 (s, 0.6H,
CH3),1.70 (s, 2.4H, CH3),1.95 (s, 2.4H, CH3), 2.30 (s, 0.6H, CH3), 4.02 (s,
0.2H), 4.37 (s, 0.2H), 4.59 (s, 0.8H), 4.95 (s, 0.8H), 5.36 (s, 0.2H), 5.50
(s, 0.8H), 6.75e6.97 (m, 4H, Ar), 7.04e7.21 (m,10H, Ar), 7.27e7.44 (m,
3H, Ar). 13C NMR (CDCl3, 75 MHz, TMS)
d 21.7, 21.9, 22.0, 22.3, 23.3,
23.4, 23.5, 40.2, 43.1,115.8,116.0,116.1,116.2,116.3,119.4,121.9,122.0,
122.3,122.4,122.6,123.9,125.4,125.7,125.9,126.1,127.0,127.1,127.2,
127.3, 127.4, 127.60, 127.64, 127.8, 128.2, 128.8, 129.2, 129.3, 129.5,
129.8,130.6,130.7,130.9,131.0,131.3,132.5,133.6,133.7,135.5,136.7,
137.0, 138.9, 141.2, 141.6, 141.8, 142.0, 142.49, 142.53, 142.8, 142.9,
(CH2Cl2)
n 3075, 2906, 2853, 1715, 1601, 1574, 1504, 1481, 1450,
1367, 1322, 1258, 1222, 1096, 905, 751 cmꢁ1. MS (ESI) m/e 473.5
(Mþþ1). HRMS (MALDI) calcd for C34H30OF: 473.2276, found:
473.2275.
143.2,150.9,151.4,152.9,153.0. IR (CH2Cl2) n 3057, 3013, 2922, 2852,
1716, 1600, 1574, 1481, 1451, 1367, 1326, 1259, 1218, 1096, 905,
752 cmꢁ1. MS (%) m/e 468 (Mþ, 21.60), 453 (1.18), 425 (2.07), 287
(13.83), 215 (2.08), 181 (100.00), 165 (1.87), 152 (3.20). HRMS (EI)
calcd for C35H32O: 468.2453, found: 468.2451.
4.4. The procedure for the reaction of VDCP 1a with DDQ in
DCE
Under argon atmosphere, vinylidenecyclopropane 1a (0.2 mmol)
and was added into a Schlenk tube, and then the solvent of DCE
(2.0 mL) was added. The reaction mixture was stirred at 0 ꢀC for
a while until the solid substrates dissolved, then, DDQ (0.4 mmol)
was added under argon. The reaction was stirred at 0 ꢀC for 20 min.
Then, the solvent was removed under reduced pressure and the
residue was purified by a flash column chromatography (SiO2) to
give the corresponding products 3a0 in moderate to good yields.
4.3.7. Compound 3g. (A E/Z mixture, ratio¼1.2:1.0). A white solid,
mp: 133e135 ꢀC. 1H NMR (CDCl3, 300 MHz, TMS)
d 1.22 (s, 1.65H,
CH3), 1.23 (s, 1.35H, CH3), 1.26 (s, 1.65H, CH3), 1.30 (s, 1.35H, CH3),
1.41 (s, 1.65H, CH3), 1.43 (s, 1.35H, CH3), 2.25 (s, 1.35H, CH3), 2.33 (s,
1.65H, CH3), 4.12 (s, 0.55H), 4.17 (s, 0.45H), 4.66 (s, 0.55H), 4.68 (s,
0.45H), 5.55 (s, 0.45H), 5.60 (s, 0.55H), 6.81e6.98 (m, 5H, Ar),
7.09e7.18 (m, 6H, Ar), 7.22e7.38 (m, 6H, Ar). 13C NMR (CDCl3,
75 MHz, TMS)
d
21.1, 21.2, 21.8, 21.9, 22.8, 22.9, 23.19, 23.22, 40.16,
4.4.1. Compound 3a0. A white solid, mp: 142e144 ꢀC. 1H NMR
40.22, 115.8, 116.0, 118.7, 118.8, 121.85, 121.89, 122.0, 122.26, 122.32,
123.1, 123.2, 126.1, 126.6, 127.2, 127.5, 127.6, 128.0, 128.6, 129.01,
129.05, 129.1, 129.2, 129.27, 129.32, 129.4, 129.5, 130.1, 130.2, 132.5,
(CDCl3, 400 MHz, TMS) d 1.47 (s, 3H, CH3), 1.69 (s, 3H, CH3), 1.84 (s,
3H, CH3), 3.84e3.85 (m, 1H), 4.65e4.66 (m, 1H), 7.11e7.14 (m, 2H,
Ar), 7.43e7.44 (m, 3H, Ar), 7.60e7.68 (m, 2H, Ar), 7.76e7.79 (m, 1H,

7110
W. Yuan, M. Shi / Tetrahedron 66 (2010) 7104e7111
Ar), 8.35e8.37 (m, 1H, Ar). 13C NMR (CDCl3, 100 MHz, TMS)
22.1, 22.7, 115.17, 115.22, 116.0, 116.7, 118.0, 125.9, 127.6, 127.7, 128.3,
129.0, 129.4, 130.0, 130.4, 131.3, 133.7, 134.0, 135.9, 136.1, 139.2,
d
21.4,
CH3), 0.88 (s, 3H, CH3), 1.49 (s, 3H, CH3), 1.74e1.83 (m, 1H), 6.52 (dd,
J¼7.8,1.5 Hz,1H, Ar), 6.65 (dd, J¼7.8,1.5 Hz,1H, Ar), 6.82e6.94 (m, 2H,
Ar), 7.10e7.14 (m, 3H, Ar), 7.19e7.37 (m, 8H, Ar). 13C NMR (CDCl3,
141.9, 145.2. IR (CH2Cl2)
n
2925, 2854, 2228, 1721, 1557, 1489, 1442,
75 MHz, TMS)d 20.7, 21.0, 21.1, 24.1, 33.3, 59.7,116.6,117.1,120.9,122.2,
122.6, 122.8, 123.1, 125.5, 127.7, 128.45, 128.52, 129.3, 130.1, 132.2,
132.3,133.2,133.67,133.72,133.9,143.6,152.78,152.81,156.0,159.0. IR
1372, 1104, 1029, 765, 701 cmꢁ1. MS (%) m/e 348 (Mþ, 94.19), 333
(58.04), 318 (9.49), 306 (10.66), 292 (100.00), 265 (28.14), 240
(6.60), 81 (22.33). Anal. Calcd for C25H20N2: C, 86.17; H, 5.79; N,
8.04. Found: C, 86.05; H, 5.80; N, 7.96.
(CH2Cl2) n 2959, 2918, 2869, 1600,1572,1479,1440,1306, 1284,1240,
1090, 834, 751 cmꢁ1. MS (%) m/e 522 (Mþ, 100.00), 507 (44.31), 479
(50.14), 465 (38.07), 444 (12.89), 337 (7.93), 255 (5.25), 181 (26.29).
HRMS (EI) calcd for C34H28OCl2: 522.1517, found: 522.1520.
4.5. General procedure for the reactions of 3 in the presence
of in the presence of BF3$OEt2 (10 mol %) at 70 ꢀC
4.5.5. Compound 4e. Awhite solid, mp: 207e209 ꢀC.1H NMR (CDCl3,
Under argon atmosphere, 3 (1.0 M in DCE) was dissolved in DCE
in a Schlenk tube, then, BF3$OEt2 (10 mol %) was inserted into the
tube. The reaction mixture was stirred at 70 ꢀC until the reaction
completed within 3 h. Then, the solvent was removed under re-
duced pressure and the residue was purified by a flash column
chromatography (SiO2) to give the corresponding products 4 in
moderate to good yields.
300 MHz, TMS)
d
0.29 (3H, d, J¼7.2 Hz, CH3), 0.37 (3H, d, J¼7.2 Hz,
CH3), 0.88 (s, 3H, CH3), 1.49 (s, 3H, CH3), 1.73e1.83 (m, 1H), 6.51 (dd,
J¼6.6,1.2 Hz,1H, Ar), 6.65(dd, J¼6.6,1.2 Hz,1H, Ar), 6.83e6.94(m, 2H,
Ar), 7.10e7.28 (m, 8H, Ar), 7.45e7.52 (m, 3H, Ar). 13C NMR (CDCl3,
75 MHz, TMS)d 20.7, 20.9, 21.1, 24.1, 33.3, 59.7,116.6,117.1,120.2,121.3,
121.4, 122.1, 122.5, 122.9, 123.1, 128.3, 128.4, 128.5, 129.3, 130.4, 130.6,
131.4, 132.2, 133.8, 133.9, 134.1, 144.0, 152.76, 152.79, 156.2, 159.0. IR
(CH2Cl2) n 2958, 2921, 2868, 2851, 1600,1571, 1478, 1440, 1284, 1239,
4.5.1. Compound 4a. A white solid, mp: 188e190 ꢀC. 1H NMR
1011, 831, 752 cmꢁ1. MS (%) m/e 612 (Mþ, 100.00), 497 (13.50), 569
(21.46), 518 (77.48), 490 (41.35), 475 (9.72), 242 (13.19), 181 (17.98).
HRMS (EI) calcd for C34H28Br2O: 610.0507, found: 610.0509.
(CDCl3, 400 MHz, TMS)
d
0.27 (3H, d, J¼7.6 Hz, CH3), 0.38 (3H, d,
J¼6.8 Hz, CH3), 0.91 (s, 3H, CH3), 1.49 (s, 3H, CH3), 1.76e1.87 (m, 1H),
6.54 (dd, J¼8.0, 2.0 Hz, 1H, Ar), 6.68 (dd, J¼7.6, 1.2 Hz, 1H, Ar),
6.79e6.89 (m, 2H, Ar), 7.09e7.23 (m, 6H, Ar), 7.27e7.39 (m, 7H, Ar).
4.5.6. Compound 4g. (A mixture, ratio¼1.2:1). A colorless oil. 1H
13C NMR (CDCl3, 100 MHz, TMS)
d
20.7, 21.0, 24.2, 33.5, 59.7, 116.4,
NMR (CDCl3, 400 MHz, TMS)
d
0.27 (d, J¼7.2 Hz, 1.6H, CH3), 0.29
116.9, 120.2, 122.6, 122.9, 123.4, 123.8, 125.0, 126.1, 127.2, 127.3,
128.0, 128.1, 128.2, 128.6, 128.9, 129.5, 132.8, 133.3, 135.6, 135.7,
(d, J¼7.2 Hz, 1.4H, CH3), 0.36 (d, J¼7.2 Hz, 1.6H, CH3), 0.39 (d,
J¼7.2 Hz, 1.4H, CH3), 0.90 (s, 1.4H, CH3), 0.91 (s, 1.6H, CH3), 1.48 (s,
1.6H, CH3), 1.49 (s, 1.4H, CH3), 1.78e1.87 (m, 1H), 2.30 (s, 1.6H,
CH3), 2.37 (s, 1.4H, CH3), 6.52e6.57 (m, 1H, Ar), 6.67e6.71 (m, 1H,
Ar), 6.78e6.96 (m, 2H, Ar), 7.08e7.38 (m, 12H, Ar). 13C NMR
145.6, 152.98, 153.04, 154.5, 158.2. IR (CH2Cl2)
n 3068, 2960, 2901,
2869, 1598, 1571, 1476, 1441, 1243, 750, 698 cmꢁ1. MS (%) m/e 454
(Mþ, 87.02), 439 (78.16), 411 (100.00), 397 (71.36), 381 (13.24), 303
(25.44), 269 (16.52), 181 (38.48). HRMS (EI) calcd for C34H30O:
454.2297, found: 454.2296.
(CDCl3, 75 MHz, TMS)
d 20.7, 21.0, 21.1, 21.3, 21.5, 24.1, 24.2, 33.4,
33.5, 59.5, 59.6, 116.30, 116.34, 116.8, 116.9, 120.0, 120.3, 122.60,
122.62, 122.9, 123.5, 123.6, 123.9, 124.0, 125.0, 125.7, 126.1, 127.1,
127.2, 127.95, 128.00, 128.04, 128.1, 128.4, 128.67, 128,71, 128.75,
128.78, 128.8, 129.0, 129.1, 129.2, 129.5, 129.7, 132.7, 132.9, 133.1,
133.2, 135.47, 135.55, 135.9, 136.8, 142.9, 145.7, 152.88, 152.93,
4.5.2. Compound 4b. A white solid, mp: 175e177 ꢀC. 1H NMR
(CDCl3, 300 MHz, TMS)
d
0.27 (3H, d, J¼7.2 Hz, CH3), 0.37 (3H, d,
J¼7.2 Hz, CH3), 0.89 (s, 3H, CH3), 1.49 (s, 3H, CH3), 1.74e1.84 (m, 1H),
6.53 (dd, J¼7.8, 1.5 Hz, 1H, Ar), 6.66 (dd, J¼7.8, 1.5 Hz, 1H, Ar),
6.82e6.93 (m, 3H, Ar), 7.01e7.14 (m, 5H, Ar), 7.21e7.36 (m, 5H, Ar).
152.99, 153.04, 154.5, 154.9, 157.2, 157.7. IR (CH2Cl2)
n 3026, 2961,
2922, 2870, 1599, 1571, 1477, 1441, 1304, 1283, 1243, 821,
750 cmꢁ1. MS (%) m/e 468 (Mþ, 87.65), 453 (77.52), 425 (100.00),
411 (76.81), 395 (14.92), 317 (15.74), 205 (12.76), 181 (29.23).
HRMS (EI) calcd for C35H32O: 468.2453, found: 468.2460.
13C NMR (CDCl3, 100 MHz, TMS)
d 20.7, 21.0, 21.1, 24.1, 33.4, 59.6 (d,
JCeF¼1.7 Hz), 112.7 (d, JCeF¼23.0 Hz), 114.3 (d, JCeF¼22.5 Hz), 115.1
(d, JCeF¼20.8 Hz), 116.5, 117.1, 120.8, 120.9, 122.7, 122.8, 123.0, 123.1,
128.4, 129.3, 130.4 (d, JCeF¼7.8 Hz), 131.4 (d, JCeF¼3.4 Hz), 132.5,
133.7, 141.1 (d, JCeF¼1.7 Hz), 152.8, 152.9, 156.2, 156.3, 158.06, 158.11,
4.5.7. Compound 4h. A white solid, mp: 184e186 ꢀC. 1H NMR
162.0 (d, JCeF¼245.06 Hz), 162.1 (d, JCeF¼243.8 Hz). IR (CH2Cl2)
n
(CDCl3, 300 MHz, TMS)
d
0.28 (3H, d, J¼6.9 Hz, CH3), 0.37 (3H, d,
2960, 2924, 2870, 1602, 1572, 1506, 1477, 1439, 1234, 1156, 886, 836,
754 cmꢁ1. MS (%) m/e 490 (Mþ, 100.00), 475 (37.58), 447 (64.75),
433 (33.09), 339 (15.39), 286 (9.30), 273 (6.55), 181 (16.32). HRMS
(EI) calcd for C34H28OF2: 490.2108, found: 490.2112.
J¼6.9 Hz, CH3), 0.90 (s, 3H, CH3), 1.48 (s, 3H, CH3), 1.77e1.88 (m, 1H),
2.29 (s, 3H, CH3), 2.36 (s, 3H, CH3), 6.55 (d, J¼7.8 Hz, 1H, Ar), 6.70 (d,
J¼7.8 Hz, 1H, Ar), 6.78e6.90 (m, 2H, Ar), 7.07e7.28 (m, 11H, Ar). 13C
NMR (CDCl3, 75 MHz, TMS)
d 20.7, 20.9, 21.1, 21.3, 21.5, 24.1, 33.4,
59.4, 116.2, 116.8, 119.9, 122.6, 122.8, 123.7, 124.1, 125.7, 127.9, 128.0,
128.66, 128.71, 128.8, 129.7, 132.88, 132.94, 133.0, 135.4, 135.8, 136.6,
4.5.3. Compound 4c. (Amixture, ratio¼1.2:1). Acolorlessoil.1HNMR
(CDCl3, 300 MHz, TMS)
d
0.27 (d, J¼7.2 Hz, 1.4H), 0.29 (d, J¼7.2 Hz,
143.0, 152.88, 152.90, 154.9, 156.7. IR (CH2Cl2) n 3023, 2963, 2919,
1.6H), 0.36 (d, J¼7.2 Hz, 1.4H), 0.39 (d, J¼7.2 Hz, 1.6H), 0.89 (s, 1.6H),
0.90 (s,1.4H),1.48 (s,1.4H),1.50 (s,1.6H),1.74e1.86 (m,1H), 6.50e6.56
(m, 1H, Ar), 6.64e6.69 (m, 1H, Ar), 6.79e6.93 (m, 2H, Ar), 7.09e7.25
(m, 5H, Ar), 7.28e7.37 (m, 7H, Ar). 13C NMR (CDCl3, 75 MHz, TMS)
2866, 1599, 1572, 1508, 1477, 1441, 1304, 1283, 1244, 756 cmꢁ1. MS
(%) m/e 482 (Mþ, 100.00), 467 (77.79), 439 (92.01), 425 (90.18), 331
(12.52), 282 (6.57), 212 (5.42), 181 (24.09). HRMS (EI) calcd for
C36H34O: 482.2610, found: 482.2608.
d
20.7, 20.9, 21.1, 21.3, 21.5, 24.1, 33.4, 59.4, 116.2, 116.8, 119.9, 122.6,
122.8, 123.7, 124.1, 125.7, 127.9, 128.0, 128.66, 128.71, 128.8, 129.7,
132.88, 132.94, 133.0, 135.4, 135.8, 136.6, 143.0, 152.88, 152.90, 154.9,
4.5.8. Compound 4i. A white solid, mp: 182e184 ꢀC. 1H NMR (CDCl3,
300 MHz, TMS)
d
0.28 (3H, d, J¼7.2 Hz, CH3), 0.37 (3H, d, J¼7.2 Hz, CH3),
156.7. IR (CH2Cl2)
n
2958, 2871, 1600, 1572, 1477, 1442, 1303, 1283,
0.90 (s, 3H, CH3),1.48 (s, 3H, CH3),1.81e1.88 (m, 1H), 3.69 (s, 3H, OCH3),
3.81 (s, 3H, OCH3), 6.55 (d, J¼8.0 Hz, 1H, Ar), 6.70e6.71 (m, 2H, Ar),
6.79e6.90 (m, 5H, Ar), 7.07e7.32 (m, 7H, Ar). 13C NMR (CDCl3, 75 MHz,
1244, 750 cmꢁ1. MS (%) m/e 488 (Mþ, 100.00), 473 (72.32), 445
(89.70), 431 (66.74), 395 (10.89), 337 (11.52), 197 (17.47), 181 (41.03).
HRMS (EI) calcd for C34H29OCl: 488.1907, found: 488.1908.
TMS) d20.6, 21.0, 21.1, 24.0, 33.4, 55.1, 55.5, 59.5,110.8,113.0,113.4,116.2,
116.8, 120.7, 122.7, 122.9, 123.8, 124.1, 128.0, 128.3, 128.8, 129.6, 129.9,
133.0, 133.1, 134.6, 138.6, 152.89, 152.94, 155.4, 156.1, 158.6, 158.7. IR
4.5.4. Compound 4d. Awhitesolid,mp:205e207 ꢀC.1HNMR(CDCl3,
300 MHz, TMS)
d
0.29 (3H, d, J¼7.2 Hz, CH3), 0.37 (3H, d, J¼7.2 Hz,
(CH2Cl2) n 2960, 2932, 2869, 2834, 1611, 1570, 1507, 1476, 1439, 1278,

W. Yuan, M. Shi / Tetrahedron 66 (2010) 7104e7111
7111
1245, 1034, 751 cmꢁ1. MS (%) m/e 514 (Mþ, 100.00), 499 (47.51), 471
(62.57), 457 (33.69), 441 (8.36), 363 (4.74), 255 (2.38),181 (12.12). Anal.
Calcd for C36H34O3: C, 84.01; H, 6.66. Found: C, 83.93; H, 6.66.
Misawa, Y.; Ando, W. Tetrahedron Lett. 1990, 31,1173e1176; (j) Mizuno, K.; Sugita, H.;
Isagawa, K.; Goto, M.; Otsuji, Y. Tetrahedron Lett.1993, 34, 5737e5738; (k) Mizuno, K.;
Sugita, H.; Hirai, T.; Maeda, H. Chem. Lett. 2000, 1144e1145; (l) Mizuno, K.; Nire, K.;
Sugita, H.; Maeda, H. Tetrahedron Lett. 2001, 42, 2689e2692.
4. Wu, L.; Shi, M.; Li, Y.-X. Chem.dEur. J. 2010, 16, 5163e5172.
5. (a) Benfatti, F.; Capdevila, M. G.; Zoli, L.; Benedetto, E.; Cozzi, P. G. Chem. Commun.
2009, 5919e5921; (b) Zhang, Y.; Li, C.-J. J. Am. Chem. Soc. 2006, 128, 4242e4243.
6. The crystal data of 3a0 have been deposited in CCDC with number 764682.
Empirical Formula: C25H20N2; Formula Weight: 348.43; Crystal Color, Habit:
colorless, prismatic; Crystal System: Monoclinic; Lattice Type: Primitive;
Crystal size: 0.415ꢂ0.360ꢂ0.287; Lattice Parameters: a¼14.9661 (16) $, b¼8.
Acknowledgements
Financial support from the Shanghai Municipal Committee of
Science and Technology (08dj1400100-2), National Basic Research
Program of China (973)-2009CB825300, and the National Natural
Science Foundation of China (20872162, 20672127, 20732008,
20821002 and 20702013) are greatly acknowledged.
1905 (9) $, c¼16.7871 (19) $,
a
¼90ꢀ,
b
¼109.339 (2)ꢀ,
g
¼90ꢀ, V¼1941.7 (4) $3;
Space group: P2 (1)/n; Z¼4; Dcalcd¼1.192 g/cm3; F000¼736; Diffractometer: Ri-
gaku AFC7R; Residuals: R; Rw: 0.068, 0.2143.
7. The plausible reaction mechanism of VDCP 1a reacting with DDQ has been
shown belows:
Supplementary data
Spectroscopic charts of the compounds shown in Tables 1e4,
X-ray crystal data of 3a0 and 4i and the detailed descriptions of ex-
perimental procedures. Thismaterialisavailablefreeofchargeviathe
Internet at the Website. Supplementary data associated with this
article can be found in online version at doi:10.1016/j.tet.2010.07.004.
References and notes
1. For the synthesis of diarylvinylidenecyclopropanes, please see: (a) Isagawa, K.;
Mizuno, K.; Sugita, H.; Otsuji, Y. J. Chem. Soc., Perkin Trans. 11991, 2283e2285 and
references therein; (b) Al-Dulayymi, J. R.; Baird, M. S. J. Chem. Soc., Perkin Trans. 1
1994, 1547e1548 For some other papers related to vinylidenecyclopropanes: (c)
Maeda, H.; Hirai, T.; Sugimoto, A.; Mizuno, K. J. Org. Chem. 2003, 68, 7700e7706;
(d) Pasto, D. J.; Brophy, J. E. J. Org. Chem. 1991, 56, 4554e4556 For a recent review,
see: (e) Maeda, H.; Mizuno, K. J. Synth. Org. Chem. Jpn. 2004, 62, 1014e1025.
2. (a) Xu, G.-C.; Liu, L.-P.; Lu, J.-M.; Shi, M. J. Am. Chem. Soc. 2005, 127,14552e14553;
(b) Shi, M.; Lu, J.-M.; Xu, G.-C. Tetrahedron Lett. 2005, 46, 4745e4748; (c) Li, Q.-J.;
Shi, M.; Timmons, C.; Li, G.-G. Org. Lett. 2006, 8, 625e628; (d) Shi, M.; Lu, J.-M.
Synlett 2005, 2352e2356; (e) Lu, J.-M.; Shi, M. Org. Lett. 2007, 9,1805e1808; (f) Lu,
J.-M.; Shi, M. Org. Lett. 2006, 8, 5317e5320; (g) Shi, M.; Li, W. Tetrahedron 2007, 63,
6654e6660; (h) Shi, M.; Yao, L.-F. Chem.dEur. J. 2008,14, 8725e8731; (i) Lu, J.-M.;
Zhu, Z.-B.; Shi, M. Chem.dEur. J. 2009, 15, 963e971; (j) Zhu, Z.-B.; Shi, M. Chem.d
Eur. J. 2008, 14, 10219e10222; (k) Shi, M.; Yao, L.-F. Chem.dEur. J. 2008, 14,
8725e8731; (l) Lu, J. M.; Shi, M. J. Org Chem. 2008, 73, 2206e2210; (m) Zhang, Y.-
P.; Lu, J.-M.; Xu, G.-C.; Shi, M. J. Org. Chem. 2007, 72, 509e516; (n) Lu, J.-M.; Shi, M.
Tetrahedron 2007, 63, 7545e7549.
8. (a) Yi, C.-Y.; Liu, S.-X.; Neels, A.; Renaud, P.; Decurtins, S. Org. Lett. 2007, 9,
1805e1808; (b) Shin, J.-Y.; Patrick, B. O.; Dolphin, D. Org. Biomol. Chem. 2009, 7,
2032e2035.
9. The crystal data of 4i have been deposited in CCDC with number 773387.
Empirical Formula: C36H34O3; Formula Weight: 514.63; Crystal Color,
Habit: colorless, prismatic; Crystal System: Triclinic; Lattice Type: Prim-
itive; Crystal size: 0.362ꢂ0.341ꢂ0.280; Lattice Parameters: a¼9.4647
ꢀ
(10) $, b¼11.3691 (9) $, c¼14.6352 (14) $,
a
¼84.563 (2)ꢀ,
b
¼89.929 (2)
,
g
¼66.560 (2)ꢀ, V¼1437.2 (2) $3; space group: Pꢁ1; Z¼2; Dcalcd¼1.189 g/
cm3; F000¼548; Diffractometer: Rigaku AFC7R; Residuals: R; Rw: 0.0777,
0.2452.
10. For the related papers with that a trace of water is required to trigger the first
formation of cation
B
by means of Lewis acid BF3 (BF3þH2OþMe2CH]
3. (a)Huang, X.; Su, C.-L.;Liu, Q.-Y.; Song, Y.-T. Synlett 2008, 229e231; (b) Fall, Y.; Doucet,
H.; Santelli, M. Tetrahedron Lett. 2007, 48, 3579e3581; (c) Poutsma, M. L.; Ibarbia, P. A.
J. Am. Chem. Soc.1971, 93, 440e450; (d) Smadja, W. Chem. Rev.1983, 83, 263e320; (e)
Hendrick, M. E.; Hardie, J. A.; Jones, M., Jr. J. Org. Chem.1971, 36, 3061e3062; (f) Sugita,
H.; Mizuno, K.; Saito, T.; Isagawa, K.; Otsuji, Y. Tetrahedron Lett. 1992, 33, 2539e2542;
(g) Mizuno, K.; Sugita, H.; Kamada, T.; Otsuji, Y. Chem. Lett. 1994, 449e452 and ref-
erences citedtherein; (h) Sydnes, L. K. Chem. Rev. 2003,103,1133e1150;(i)Akasaka, T.;
CH2/Me3CHþBF3OHꢁ). Please see: (a) Evans, A. G.; Holden, D.; Plesch, P.;
Polanyi, M.; Skinner, H. A.; Weinberger, M. A. Nature 1946, 157, 102e103; (b)
Evans, A. G.; Meadows, G. W.; Polanyi, M.; Skinner, H. A.; Weinberger, M. A.
Nature 1946, 158, 94e95; (c) Evans, A. G.; Polanyi, M. J. Chem. Soc. 1947,
252e257; (d) Prakash, G. K. S.; Mathew, T.; Hoole, D.; Esterves, P. M.; Wang, Q.;
Rasul, G.; Olah, G. A. J. Am. Chem. Soc. 2004, 126, 15770e15776.