Ring-opening reactions of cyclopropenedicarboxylates with organolithiums and organozincs

Article abstract of DOI:10.1002/ejoc.201201588

Ring-opening reactions of cyclopropenedicarboxylates with organolithiums and organozincs have been studied. Organolithiums and dialkyl- or diphenylzincs afforded a series of 1-alkenyl malonates with attack occurring by the organic group from the organometallic reagent at the less substituted sp ²-hybridized carbon of the cyclopropene moiety. Mechanistic studies proved both anion and dianion intermediates are involved in the reactions with organolithiums. Phenylcyclopropenedicarboxylate and phenylzinc bromide underwent a ring-opening dimerization to afford a 1,4-enyne product. Ring-opening reactions of cyclopropenedicarboxylates with organolithiums and dialkyl- or diphenylzinc afford a series of 1-alkenyl malonates with high regio- and stereoselectivity. The reaction between phenylcyclopropenedicarboxylate and phenylzinc bromide led to a ring-opening dimerization to give a 1,4-enyne compound as the product. Copyright

Full text of DOI:10.1002/ejoc.201201588

FULL PAPER
DOI: 10.1002/ejoc.201201588
Ring-Opening Reactions of Cyclopropenedicarboxylates with Organolithiums
and Organozincs
Yu Liu,[a] Qiong Yu,[a] and Shengming Ma*[a,b]
Keywords: Small ring systems / Cleavage reactions / Lithiation / Isotopic labeling / Regioselectivity / Alkenes
Ring-opening reactions of cyclopropenedicarboxylates with
organolithiums and organozincs have been studied. Organo-
lithiums and dialkyl- or diphenylzincs afforded a series of 1-
alkenyl malonates with attack occurring by the organic
group from the organometallic reagent at the less substituted
sp2-hybridized carbon of the cyclopropene moiety. Mechan-
istic studies proved both anion and dianion intermediates are
involved in the reactions with organolithiums. Phenylcy-
clopropenedicarboxylate and phenylzinc bromide under-
went a ring-opening dimerization to afford a 1,4-enyne prod-
uct.
opening reaction of doubly activated cyclopropenes with
Grignard reagents to give a series of ring-opening products,
that is, multisubstituted alkenes, with high regio- and stereo-
selectivity; see Scheme 1, Equation (2).[4] Herein, we report
additional investigations of the reactions of cyclopropene-
dicarboxylates with organolithiums and organozincs.[5]
Introduction
Cyclopropene derivatives are readily available,[1] highly
strained[2] molecules that easily undergo addition reactions
at their intrinsic double bond as well as C–C bond cleavage
reactions to afford cyclopropane derivatives and ring-open-
ing products, respectively.[1,3] Organometallic reagents such
as Grignard reagents, organozincs, and organolithiums have
been shown to react with cyclopropenes through deproton-
ation or carbometallation of the double bonds, resulting in
most cases in retention of the small ring; see Scheme 1,
Equation (1).[1,3] Recently, we reported the interesting ring-
Results and Discussion
The reaction between dimethyl 2-phenylcycloprop-2-ene-
1,1-dicarboxylate (1a) and nBuLi was first tested. In con-
trast to a previous study,[1,3] 1-alkenyl malonate 2aa was
indeed formed as the single product[4] of the reaction, in
which the butyl group from nBuLi attacked the less substi-
tuted sp2-hybridized carbon to afford the product with the
phenyl and butyl groups in the cis orientation (see Table 1,
Entry 1). Neither of the addition products 3a or 3b from
the reaction between the ester groups of 1a and nBuLi was
formed. There was an obvious effect from varying the tem-
perature (see Table 1, Entries 1–4), and conducting the reac-
tion at –60 °C afforded 2aa in 73% yield (see Table 1, En-
try 3). Further screening of the reaction conditions showed
that a higher loading of nBuLi led to a higher yield (see
Table 1, Entries 3 and 5–7). Changing the solvent from
tetrahydrofuran (THF) to diethyl ether or toluene did not
afford better results (see Table 1, Entries 8 and 9). Finally,
we chose to use 2.5 equiv. of the organolithium reagent and
THF as the solvent at –60 °C as the standard conditions
(see Table 1, Entry 6).
Scheme 1. Previous reports of reactions between cyclopropenes and
organolithiums, organozincs, and Grignard reagents.
[a] Shanghai Key Laboratory of Green Chemistry and Chemical
Process, Department of Chemistry, East China Normal
University,
3663 North Zhongshan Lu, Shanghai 200062, P. R. China
[b] State Key Laboratory of Organometallic Chemistry, Shanghai
Institute of Organic Chemistry, Chinese Academy of Sciences,
345 Lingling Lu, Shanghai 200032, P. R. China
Fax: +86-21-6260-9305
To define the scope of the substrates, a series of arylcy-
clopropenes were tested with different organolithiums (see
Table 2). The reactions between phenylcyclopropene 1a and
different organolithiums revealed a steric effect, that is, less
hindered organolithiums gave higher yields Ϫ MeLi Ͼ
nBuLi Ͼ sBuLi Ͼ tBuLi (see Table 2, Entries 1–4). Naphth-
E-mail: masm@sioc.ac.cn
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201201588.
Eur. J. Org. Chem. 2013, 3033–3040
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
3033

Y. Liu, Q. Yu, S. Ma
FULL PAPER
Table 1. Optimization of the reaction conditions.[a]
high yields, and no deprotonation reaction occurred at the
site of the aromatic methyl group. Phenylcyclopropene 1e,
which had a tert-butyl substitutent, led to moderate yields
of the ring-opening products (see Table 2, Entries 10 and
11). Phenylcyclopropene 1f with an electron-withdrawing
chlorine atom could also be transformed into the corre-
sponding alkenes in good yields (see Table 2, Entries 12 and
13).
Further studies showed that n-butyl- and n-octyl-substi-
tuted substrates 1g and 1h could also be transformed into
the corresponding ring-opening products, although the
yields were lower (see Scheme 2).
Entry
nBuLi
[equiv.]
Solvent
Temp.
[°C]
% Yield
% Recovery
2aa[b]
1a[b]
1
2.0
2.0
2.0
2.0
1.2
2.5
4.0
2.5
2.5
THF
THF
THF
THF
THF
THF
THF
Et2O
toluene
–20
–40
–60
–80
–60
–60
–60
–60
–60
35
44
73
50
25
80
85
29
20
0
0
0
29
41
0
0
17
4
2
3[c]
4
5[c]
6
7
8
9
[a] nBuLi was added to a solution of 1a (0.2 mmol) in THF (2 mL)
at the indicated temperature. After complete conversion of the
starting material, the reaction was quenched with a saturated solu-
Scheme 2. Ring-opening reactions of alkylcyclopropenedicarboxyl-
ates with organolithiums.
1
tion of NH4Cl. [b] Determined by H NMR analysis of the crude
mixture. [c] The reaction time was 1.5 h.
Quenching the reaction between 1a and nBuLi with
AcOD afforded dideuterated product 2aa-d2. The sp3-hy-
bridized carbon was 97% deuterated according to the H
yl-substituted substrate 1b afforded the ring-opening
product in a higher yield (see Table 2, Entry 5). Phenylcy-
clopropenes with a p-methyl (see Table 2, Entries 6 and 7)
or m-methyl substitutent (see Table 2, Entries 8 and 9) were
both compatible, generating the corresponding alkenes in
1
NMR analysis of the crude product, but this decreased to
31% after chromatographic purification on silica gel be-
cause of the facile exchange between this acidic deuterium
and a hydrogen atom from the surroundings. However, the
sp2-hybridized carbon was only 63% deuterated [see
Scheme 3, Equation (1)]. An isotopic labeling reaction was
then conducted between 1a-d and nBuLi to afford 2aa-d
with 18% deuteration [see Scheme 3, Equation (2)]. Finally,
the treatment of 2aa with nBuLi followed by AcOD did
not result in any deuteration of the olefinic C–H bond [see
Scheme 3, Equation (3)].
Table 2. The scope of the ring-opening reaction of cyclopropenedi-
carboxylates 1 with organolithiums.[a]
On the basis of the above studies, we reason that two
pathways may be involved (see Scheme 4). The organo-
lithium reagent may directly attack cyclopropene 1a to give
allylic lithium intermediate A (see Scheme 4, path a).[6] An-
other pathway includes deprotonation[7] and then attack of
the in situ formed cyclopropenyllithium intermediate B[4] by
nBuLi to generate dilithium intermediate C (see Scheme 4,
path b). The ratio of the two intermediates A/C is about 1:4
according to the deuterium-labeling results. Both intermedi-
ates were converted into product 2aa after quenching with
aqueous saturated NH4Cl solution. The possibility of gen-
erating intermediate C from A may be safely excluded on
the basis of the results shown in Equation (3) of Scheme 3.
Additional studies showed that dialkyl- or diphenylzinc
reagents could also undergo a reaction with cyclopropene
1a to give similar results, but the yields were lower [see
Scheme 5, Equation (1)]. Interestingly, changing the or-
ganozinc reagents to phenylzinc bromide afforded the ring-
Entry
Ar
R
Isolated yield of 2
[%]
1
2
Ph (1a)
Me
86 (2ab)
77 (2aa)
48 (2ac)
29 (2ad)
88 (2ba)
73 (2ca)
78 (2cb)
72 (2da)
78 (2db)
42 (2ea)
42 (2eb)
60 (2fa)
63 (2fb)
Ph (1a)
nBu
sBu
tBu
nBu
nBu
Me
nBu
Me
nBu
Me
3
Ph (1a)
4[b]
5
Ph (1a)
2-naphthyl (1b)
p-MeC6H4 (1c)
p-MeC6H4 (1c)
m-MeC6H4 (1d)
m-MeC6H4 (1d)
p-tBuC6H4 (1e)
p-tBuC6H4 (1e)
p-ClC6H4 (1f)
p-ClC6H4 (1f)
6[c]
7
8
9
10
11
12
13[c]
nBu
Me
[a] RLi (2.5 equiv.) was added to a solution of 1 (0.2 mmol) in THF
(2 mL) at –60 °C. After complete conversion of the starting mate-
rial, the reaction was quenched with a saturated solution of NH4Cl.
[b] An unidentified byproduct was formed. [c] The reaction time
was 2.0 h.
3034
www.eurjoc.org
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2013, 3033–3040

Ring-Opening Reactions of Cyclopropenedicarboxylates
Scheme 3. Deuterium-labeling experiments.
Scheme 4. Proposed mechanism for the ring-opening reactions of cyclopropenes with organolithiums.
opening dimerization product 1,4-enyne 4 [see Scheme 5,
Equation (2)]. The structure of 4 was confirmed by an X-
ray diffraction study (see Figure 1).[8] Alkylcyclopropene 1g
was also treated with phenylzinc bromide, but this only led
to an unidentified mixture.
Figure 1. ORTEP representation of 4.
Scheme 5. Ring-opening reactions of cyclopropenes with organo-
zincs.
purification (see Scheme 6). We reason that cyclopropenyl
Quenching the reaction of 1a and PhZnBr with AcOD anion D is generated first, which then rearranges to prop-
afforded monodeuterated product 4-d with 84% deuteration argylic anion E.[7b,7e] The further attack of E on 1a leads
at the sp3-hybridized carbon, which dropped to 30% after to ring-opening dimerization product 4.
Eur. J. Org. Chem. 2013, 3033–3040
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3035

Y. Liu, Q. Yu, S. Ma
FULL PAPER
10:1 to 5:1) afforded 1b (1.2629 g, 64%) as a solid; m.p. 102–103 °C
1
(petroleum ether/CH2Cl2). H NMR (300 MHz, CDCl3): δ = 8.09
(s, 1 H, Ar), 7.95–7.80 (m, 3 H, Ar), 7.71 (d, J = 8.4 Hz, 1 H,
Ar), 7.59–7.48 (m, 2 H, Ar), 6.98 (s, 1 H, C=CH), 3.76 (s, 6 H, 2
OCH3) ppm. 13C NMR (75 MHz, CDCl3): δ = 171.1, 134.1, 133.0,
130.9, 128.7, 128.5, 127.8, 127.6, 126.8, 126.4, 121.2, 112.4, 95.6,
52.4, 33.0 ppm. MS (EI): m/z (%) = 282 (59.18) [M]+, 152 (100).
IR (neat): ν = 2924, 1738, 1712, 1291, 1065 cm–1. C H O
˜
17 14
4
(282.30): calcd. C 72.33, H 5.00; found C 72.07, H 5.01.
Dimethyl 2-(m-Tolyl)cycloprop-2-ene-1,1-dicarboxylate (1d): Fol-
lowing the general procedure for cyclopropene derivative 1b, the
reaction of 1-ethynyl-3-methylbenzene (2.3231 g, 20.0 mmol), di-
methyl 2-diazomalonate (1.0997 g, 7.0 mmol), and Rh2(OAc)4
(7.7 mg, 0.017 mmol) in CH2Cl2 (20 mL) gave the crude product.
Purification by chromatography (petroleum ether/ethyl acetate,
10:1) afforded 1d (0.9828 g, 57%) as a solid; m.p. 58–59 °C (petro-
Scheme 6. Proposed mechanism for the ring-opening-dimerization
reaction of cyclopropene 1a.
Conclusions
1
leum ether/diethyl ether). H NMR (300 MHz, CDCl3): δ = 7.46–
7.40 (m, 2 H, Ar), 7.33 (t, J = 7.8 Hz, 1 H, Ar), 7.27–7.22 (m, 1
H, Ar), 6.86 (s, 1 H, C=CH), 3.73 (s, 6 H, 2 OCH3), 2.39 (s, 3 H,
ArCH3) ppm. 13C NMR (75 MHz, CDCl3): δ = 171.2, 138.7, 131.5,
130.8, 128.8, 127.5, 123.7, 112.2, 94.9, 52.4, 32.7, 21.2 ppm. MS
In summary, we investigated the reactions between cyclo-
propenedicarboxylates and organometallic reagents such as
organolithiums and organozincs. The reactions of organo-
lithiums and dialkyl- or diphenylzincs gave similar results
with attack occurring by the organic moiety at the less sub-
stituted sp2-hybridized carbon of the cyclopropene ring to
generate multisubstituted 1-alkenyl malonates with high re-
gio- and stereoselectivity. This is intriguing, as no such ring-
opening reaction of cyclopropenes by these types of orga-
nometallic reagents has been reported.[1,3] A ring-opening
dimerization of phenylcyclopropenedicarboxylate by treat-
ment with phenylzinc bromide led to a 1,4-enyne com-
pound. Further studies are ongoing in our laboratory.
(EI): m/z (%) = 246 (37.27) [M]+, 231 (100). IR (neat): ν = 3161,
˜
1741, 1714, 1437, 1277, 1059 cm–1. C14H14O4 (246.26): calcd. C
68.28, H 5.73; found C 68.37, H 5.67.
Dimethyl 2-(4-tert-Butylphenyl)cycloprop-2-ene-1,1-dicarboxylate
(1e): Following the general procedure for cyclopropene derivative
1b, the reaction of 1-(tert-butyl)-4-ethynylbenzene (2.3602 g,
14.9 mmol), dimethyl 2-diazomalonate (0.7907 g, 5.0 mmol), and
Rh2(OAc)4 (5.6 mg, 0.013 mmol) in CH2Cl2 (20 mL) gave the crude
product. Purification by chromatography (petroleum ether/ethyl
acetate, 5:1) afforded 1e (0.8028 g, 55%) as a solid; m.p. 74–75 °C
1
(petroleum ether/diethyl ether). H NMR (300 MHz, CDCl3): δ =
7.59–7.53 (m, 2 H, Ar), 7.48–7.44 (m, 2 H, Ar), 6.83 (s, 1 H,
C=CH), 3.71 (s, 6 H, 2 OCH3), 1.32 (s, 9 H, 3 CH3) ppm. 13C NMR
(75 MHz, CDCl3): δ = 171.3, 154.1, 130.1, 125.9, 121.0, 112.0, 94.1,
52.4, 35.0, 32.7, 31.1 ppm. MS (EI): m/z (%) = 288 (35.84) [M]+,
Experimental Section
General Information: All solvents were distilled before use. CH2Cl2
was distilled from anhydrous K2CO3. THF and Et2O were distilled
from Na/benzophenone. Unless otherwise indicated, all other rea-
gents were used as received from their commercial sources. The
NMR spectroscopic data were recorded with a commercial Bruker-
300 spectrometer (300 MHz for 1H NMR, 75.4 MHz for 13C
NMR). Chemical shifts are reported in parts per million (ppm, δ).
273 (100). IR (neat): ν = 2955, 1731, 1719, 1603, 1281, 1243,
˜
1061 cm–1. C17H20O4 (288.34): calcd. C 70.81, H 6.99; found C
70.96, H 6.90.
Ring-Opening Reactions of Cyclopropenes with Organolithiums
Dimethyl (Z)-2-(1-Phenylprop-1-enyl)malonate (2ab): To a dried
Schlenk tube were added 1a (46.0 mg, 0.20 mmol) and THF (2 mL)
under Ar. After the solution was cooled to –60 °C, MeLi (3.0 m in
diethoxymethane, 0.17 mL, 0.50 mmol) was added through a sy-
ringe. The mixture was stirred at –60 °C for 2.5 h and was moni-
tored by TLC (petroleum ether/ethyl acetate, 10:1). The reaction
mixture was then quenched with a saturated aqueous NH4Cl solu-
tion (1.0 mL). Water (10 mL) was added, and the mixture was ex-
tracted with Et2O (3ϫ10 mL). The combined organic layers were
dried with anhydrous Na2SO4. Filtration, evaporation, and
chromatography on silica gel (petroleum ether/ethyl acetate, 15:1)
afforded 2ab (42.2 mg, 86%) as a liquid. 1H NMR (300 MHz,
CDCl3): δ = 7.38–7.18 (m, 5 H, Ar), 5.88 (q, J = 6.8 Hz, 1 H,
C=CH), 4.40 (s, 1 H, CH), 3.72 (s, 6 H, 2 OCH3), 1.63 (d, J =
6.6 Hz, 3 H, CH3) ppm. 13C NMR (75 MHz, CDCl3): δ = 168.6,
138.8, 133.3, 128.8, 128.15, 128.09, 127.2, 59.4, 52.6, 15.0 ppm. MS
1
The H NMR spectra were calibrated to either residual CHCl3 (δ
= 7.26 ppm) in CDCl3 or TMS (δ = 0.00 ppm), and the 13C NMR
spectra were calibrated to CDCl3 (δ = 77.0 ppm). X-ray intensity
data were measured at 293 K with a Bruker SMART APEX CCD-
based X-ray diffractometer system equipped with a fine-focus Mo-
target X-ray tube (λ = 0.71073 Å) that operated at 1,500 W. Infra-
red (IR) spectra were recorded as films with a commercial FTIR
instrument. Melting points were measured with a hot-stage melting
point apparatus. The substrates 1a,[9] 1c,[9] 1f,[10] 1g,[9] and 1h[9]
were synthesized according to previous reports. Other cyclopropene
derivatives were prepared by a similar general procedure.
Dimethyl
2-(Naphthalen-2-yl)cycloprop-2-ene-1,1-dicarboxylate
(1b): To a dried Schlenk tube were added anhydrous Rh2(OAc)4
(7.9 mg, 0.018 mmol) and CH2Cl2 (5 mL) under argon. After heat-
ing at reflux for 10 min, a solution of 2-ethynylnaphthalene
(3.2114 g, 21.1 mmol) in CH2Cl2 (5 mL) was added. Then, a solu-
tion of dimethyl 2-diazomalonate (1.1060 g, 7.0 mmol) in CH2Cl2
(10 mL) was added to the resulting mixture by a syringe pump over
a period of 2.0 h. After complete conversion of the starting material
in 2 h, as monitored by TLC, the solvent was evaporated.
Chromatography on silica gel (petroleum ether/ethyl acetate, from
(EI): m/z (%) = 248 (6.08) [M]+, 189 (100). IR (neat): ν = 2954,
˜
1736, 1494, 1436, 1367, 1314, 1233, 1195, 1148, 1072, 1028 cm–1.
HRMS: calcd. for C14H16O4 [M]+ 248.1049; found 248.1051.
Dimethyl (Z)-2-(1-Phenylhex-1-enyl)malonate (2aa)
Procedure A: Following the general procedure for 2ab, the reaction
of 1a (46.5 mg, 0.20 mmol) and nBuLi (1.6 m in hexane, 0.31 mL,
3036
www.eurjoc.org
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2013, 3033–3040

Ring-Opening Reactions of Cyclopropenedicarboxylates
0.50 mmol) in THF (2 mL) gave the crude product. Purification by
chromatography (petroleum ether/ethyl acetate, 20:1) afforded
Dimethyl 2-[(Z)-1-p-Tolylhex-1-enyl]malonate (2ca): Following the
general procedure for 2ab, the reaction of 1c (49.4 mg, 0.20 mmol)
and nBuLi (1.6 m in hexane, 0.31 mL, 0.50 mmol) in THF (2 mL)
gave the crude product. Purification by chromatography (petroleum
1
2aa[4] (44.5 mg, 77%) as a liquid. H NMR (300 MHz, CDCl3): δ
= 7.36–7.24 (m, 3 H, Ar), 7.24–7.17 (m, 2 H, Ar), 5.76 (t, J =
7.4 Hz, 1 H, C=CH), 4.38 (s, 1 H, CH), 3.71 (s, 6 H, 2 OCH3), ether/ethyl acetate, 20:1) afforded 2ca (44.8 mg, 73%) as a liquid.
1.99 (q, J = 7.2 Hz, 2 H, C=CCH2), 1.40–1.16 (m, 4 H, 2 CH2),
0.81 (t, J = 7.2 Hz, 3 H, CH3) ppm. 13C NMR (75 MHz, CDCl3):
δ = 168.6, 139.2, 134.1, 132.4, 128.8, 128.1, 127.1, 59.4, 52.5, 31.5,
28.8, 22.1, 13.8 ppm. MS (EI): m/z (%) = 290 (10.14) [M]+, 187
1H NMR (300 MHz, CDCl3): δ = 7.16–7.06 (m, 4 H, Ar), 5.72 (t,
J = 7.4 Hz, 1 H, C=CH), 4.37 (s, 1 H, CH), 3.71 (s, 6 H, 2 OCH3),
2.34 (s, 3 H, ArCH3), 1.99 (q, J = 7.1 Hz, 2 H, C=CCH2), 1.39–
1.16 (m, 4 H, 2 CH2), 0.81 (t, J = 7.2 Hz, 3 H, CH3) ppm. 13C
(100). IR (neat): ν = 2955, 2930, 2859, 1738, 1494, 1435, 1382, NMR (75 MHz, CDCl3): δ = 168.7, 136.8, 136.1, 133.9, 132.3,
˜
1313, 1238, 1195, 1149, 1073, 1030 cm–1.
128.8, 128.7, 59.5, 52.5, 31.6, 28.8, 22.1, 21.2, 13.9 ppm. MS (EI):
m/z (%) = 304 (36.84) [M]+, 245 (100). IR (neat): ν = 2956, 2927,
˜
Procedure B: Following the general procedure for 2ab, the reaction
of 1a (1.0447 g, 4.5 mmol) and nBuLi (1.6 m in hexane, 7.03 mL,
11.25 mmol) in THF (45.0 mL) with a reaction time of 2.0 h gave
the crude product. Purification by chromatography (petroleum
ether/ethyl acetate, 20:1) afforded 2aa[4] (1.0536 g, 81%).
2856, 1741, 1512, 1457, 1437, 1382, 1312, 1239, 1196, 1150,
1029 cm–1. HRMS: calcd. for C18H24O4 [M]+ 304.1675; found
304.1673.
Dimethyl 2-[(Z)-1-p-Tolylprop-1-enyl]malonate (2cb): Following the
general procedure for 2ab, the reaction of 1c (49.2 mg, 0.20 mmol)
and MeLi (3.0 m in diethoxymethane, 0.17 mL, 0.50 mmol) in THF
(2 mL) gave the crude product. Purification by chromatography
(petroleum ether/ethyl acetate, 6:1) afforded 2cb (40.8 mg, 78%) as
a liquid. 1H NMR (300 MHz, CDCl3): δ = 7.17–7.07 (m, 4 H, Ar),
5.84 (q, J = 6.8 Hz, 1 H, C=CCH), 4.38 (s, 1 H, CH), 3.71 (s, 6 H,
2 OCH3), 2.34 (s, 3 H, ArCH3), 1.63 (d, J = 6.9 Hz, 3 H,
CH3) ppm. 13C NMR (75 MHz, CDCl3): δ = 168.7, 136.8, 135.8,
133.2, 128.9, 128.7, 127.8, 59.5, 52.6, 21.2, 15.1 ppm. MS (EI): m/z
(%) = 262 (44.95) [M]+, 203 (100), 171 (100), 143 (100), 128 (100).
Dimethyl (Z)-2-(4-Methyl-1-phenylpent-1-enyl)malonate (2ac): Fol-
lowing the general procedure for 2ab, the reaction of 1a (46.3 mg,
0.20 mmol) and sBuLi (1.3 m in hexane, 0.38 mL, 0.50 mmol) in
THF (2 mL) gave the crude product. Purification by chromatog-
raphy (petroleum ether/ethyl acetate, 20:1) afforded 2ac (27.8 mg,
1
48%) as a liquid. H NMR (300 MHz, CDCl3): δ = 7.36–7.24 (m,
3 H, Ar), 7.20 (d, J = 7.8 Hz, 2 H, Ar), 5.49 (d, J = 10.5 Hz, 1 H,
C=CH), 4.34 (s, 1 H, CH), 3.71 (s, 6 H, 2 OCH3), 2.14–1.97 (m, 1
H, CH of sBu), 1.35–1.17 (m, 2 H, CH2), 0.93 (d, J = 6.6 Hz, 3 H,
C=C-C-CH3), 0.78 (t, J = 7.4 Hz, 3 H, CH3) ppm. 13C NMR
(75 MHz, CDCl3): δ = 168.6, 140.1, 139.6, 131.6, 128.8, 128.1,
127.1, 59.6, 52.50, 52.46, 35.1, 30.0, 20.6, 11.8 ppm. MS (EI): m/z
IR (neat): ν = 2991, 2952, 2922, 2856, 1739, 1613, 1566, 1513, 1438,
˜
1366, 1312, 1235, 1193, 1150, 1080, 1029 cm–1. HRMS: calcd. for
C15H18O4 [M]+ 262.1205; found 262.1208.
(%) = 290 (4.06) [M]+, 201 (100). IR (neat): ν = 2957, 1737, 1456,
˜
Dimethyl 2-[(Z)-1-m-Tolylhex-1-enyl]malonate (2da): Following the
general procedure for 2ab, the reaction of 1d (49.6 mg, 0.20 mmol)
and nBuLi (1.6 m in hexane, 0.31 mL, 0.50 mmol) in THF (2 mL)
gave the crude product. Purification by chromatography (petroleum
ether/ethyl acetate, 6:1) afforded 2da (44.0 mg, 72%) as a liquid.
1H NMR (300 MHz, CDCl3): δ = 7.21 (t, J = 7.5 Hz, 1 H, Ar),
7.07 (d, J = 7.5 Hz, 1 H, Ar), 7.03–6.96 (m, 2 H, Ar), 5.73 (t, J =
7.4 Hz, 1 H, C=CCH), 4.36 (s, 1 H, CH), 3.72 (s, 6 H, 2 OCH3),
2.34 (s, 3 H, ArCH3), 1.99 (q, J = 7.2 Hz, 2 H, C=CCH2), 1.40–
1.17 (m, 4 H, 2 CH2), 0.81 (t, J = 7.1 Hz, 3 H, CH3) ppm. 13C
NMR (75 MHz, CDCl3): δ = 168.6, 139.2, 137.6, 133.8, 132.4,
129.3, 127.95, 127.86, 125.8, 59.4, 52.5, 31.5, 28.8, 22.1, 21.4,
13.8 ppm. MS (EI): m/z (%) = 304 (15.51) [M]+, 201 (100). IR
1435, 1311, 1256, 1220, 1194, 1146, 1074, 1029 cm–1. HRMS: calcd.
for C17H22O4 [M]+ 290.1518; found 290.1517.
Dimethyl 2-[(Z)-3,3-Dimethyl-1-phenylbut-1-en-1-yl]malonate (2ad):
Following the general procedure for 2ab, the reaction of 1a
(47.0 mg, 0.20 mmol) and tBuLi (1.6 m in heptane, 0.31 mL,
0.50 mmol) in THF (2 mL) gave the crude product. Purification by
chromatography (petroleum ether/ethyl acetate, 25:1) afforded an
unidentified product (20.1 mg) and 2ad (17.0 mg, 29%) as a liquid.
1H NMR (300 MHz, CDCl3): δ = 7.29–7.23 (m, 3 H, Ar), 7.23–
7.18 (m, 2 H, Ar), 5.68 (d, J = 0.6 Hz, 1 H, C=CH), 4.21 (d, J =
0.6 Hz, 1 H, CH), 3.69 (s, 6 H, 2 OCH3), 0.87 (s, 9 H, 3 CH3) ppm.
13C NMR (75 MHz, CDCl3): δ = 168.6, 143.6, 139.6, 130.5, 129.6,
127.6, 127.2, 61.8, 52.4, 33.8, 30.8 ppm. MS (EI): m/z (%) = 290
(neat): ν = 2954, 2927, 2859, 1737, 1603, 1583, 1486, 1455, 1434,
˜
1381, 1311, 1239, 1194, 1146, 1096, 1025 cm–1. HRMS: calcd. for
C18H24O4 [M]+ 304.1675; found 304.1675.
(4.59) [M]+, 231 (100). IR (neat): ν = 2956, 2904, 2870, 1737, 1476,
˜
1461, 1435, 1363, 1313, 1262, 1221, 1197, 1149, 1075, 1030 cm–1.
HRMS: calcd. for C17H22O4 [M]+ 290.1518; found 290.1517.
Dimethyl 2-[(Z)-1-m-Tolylprop-1-enyl]malonate (2db): Following the
general procedure for 2ab, the reaction of 1d (49.4 mg, 0.20 mmol)
and MeLi (3.0 m in diethoxymethane, 0.17 mL, 0.50 mmol) in THF
(2 mL) gave the crude product. Purification by chromatography
(petroleum ether/ethyl acetate, 6:1) afforded 2db (41.1 mg, 78%) as
Dimethyl 2-[(Z)-1-(Naphthalen-2-yl)hex-1-en-1-yl]malonate (2ba):
Following the general procedure for 2ab, the reaction of 1b
(56.7 mg, 0.20 mmol) and nBuLi (1.6 m in hexane, 0.31 mL,
0.50 mmol) in THF (2 mL) gave the crude product. Purification by
chromatography (petroleum ether/ethyl acetate, 10:1) afforded 2ba
(60.5 mg, 88%) as a liquid. 1H NMR (300 MHz, CDCl3): δ = 7.93–
7.78 (m, 3 H, Ar), 7.71 (s, 1 H, Ar), 7.54–7.43 (m, 2 H, Ar), 7.38
(d, J = 8.1 Hz, 1 H, Ar), 5.88 (t, J = 7.2 Hz, 1 H, C=CH), 4.51 (s,
1 H, CH), 3.74 (s, 6 H, 2 OCH3), 2.06 (q, J = 7.2 Hz, 2 H,
C=CCH2), 1.49–1.18 (m, 4 H, 2 CH2), 0.83 (t, J = 7.2 Hz, 3 H,
CH3) ppm. 13C NMR (75 MHz, CDCl3): δ = 168.6, 136.7, 134.5,
133.1, 132.41, 132.39, 128.0, 127.7, 127.6, 127.5, 127.1, 126.0,
125.9, 59.5, 52.5, 31.5, 28.9, 22.1, 13.8 ppm. MS (EI): m/z (%) =
1
a liquid. H NMR (300 MHz, CDCl3): δ = 7.22 (t, J = 7.5 Hz, 1
H, Ar), 7.07 (d, J = 7.8 Hz, 1 H, Ar), 7.04–6.96 (m, 2 H, Ar), 5.86
(q, J = 6.8 Hz, 1 H, C=CCH), 4.38 (s, 1 H, CH), 3.72 (s, 6 H, 2
OCH3), 2.34 (s, 3 H, ArCH3), 1.63 (d, J = 7.2 Hz, 3 H, CH3) ppm.
13C NMR (75 MHz, CDCl3): δ = 168.6, 138.9, 137.7, 133.4, 129.4,
128.0, 127.9, 127.8, 125.9, 59.4, 52.6, 21.4, 15.1 ppm. MS (EI): m/z
(%) = 262 (7.28) [M]+, 203 (100). IR (neat): ν = 2953, 2920, 2859,
˜
1735, 1602, 1583, 1486, 1434, 1385, 1366, 1311, 1246, 1194, 1145,
1025 cm–1. HRMS: calcd. for C15H18O4 [M]+ 262.1205; found
262.1206.
340 (8.69) [M]+, 121 (100). IR (neat): ν = 2955, 1737, 1435, 1312,
˜
1196, 1149, 1021 cm–1. HRMS: calcd. for C21H24O4 [M]+ 340.1675;
found 340.1676.
Dimethyl 2-[(Z)-1-(4-tert-Butylphenyl)hex-1-enyl]malonate (2ea):
Following the general procedure for 2ab, the reaction of 1e
Eur. J. Org. Chem. 2013, 3033–3040
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3037

Y. Liu, Q. Yu, S. Ma
FULL PAPER
(58.0 mg, 0.20 mmol) and nBuLi (1.6 m in hexane, 0.31 mL,
0.50 mmol) in THF (2 mL) gave the crude product. Purification by
(petroleum ether/ethyl acetate, 6:1) afforded 2gb (18.3 mg, 39%) as
a liquid. H NMR (300 MHz, CDCl3): δ = 5.51 (q, J = 6.9 Hz, 1
1
chromatography (petroleum ether/ethyl acetate, 20:1) afforded 2ea
(29.2 mg, 42%) as a liquid. H NMR (300 MHz, CDCl3): δ = 7.32 = 7.7 Hz, 2 H, C=CCH2), 1.67 (d, J = 6.6 Hz, 3 H, C=CCH3),
(d, J = 8.1 Hz, 2 H, Ar), 7.12 (d, J = 8.4 Hz, 2 H, Ar), 5.73 (t, J
H, C=CCH), 4.04 (s, 1 H, CH), 3.73 (s, 6 H, 2 OCH3), 2.14 (t, J
1
1.36–1.26 (m, 4 H, 2 CH2), 0.93–0.85 (m, 3 H, CH3) ppm. 13C
= 7.4 Hz, 1 H, C=CCH), 4.37 (s, 1 H, CH), 3.71 (s, 6 H, 2 OCH3), NMR (75 MHz, CDCl3): δ = 169.1, 132.7, 126.0, 58.2, 52.5, 30.2,
2.01 (q, J = 7.1 Hz, 2 H, C=CCH2), 1.40–1.18 (m, 13 H, 2 CH2
29.9, 22.7, 13.9, 13.7 ppm. MS (EI): m/z (%) = 228 (7.72) [M]+, 169
and 3 CH3), 0.81 (t, J = 7.4 Hz, 3 H, CH3) ppm. 13C NMR
(100). IR (neat): ν = 2957, 2928, 2859, 1738, 1435, 1315, 1258,
˜
(75 MHz, CDCl3): δ = 168.7, 149.9, 136.3, 133.8, 132.2, 128.3, 1232, 1196, 1147, 1027 cm–1. HRMS: calcd. for C12H20O4 [M]+
125.0, 59.4, 52.5, 34.5, 31.6, 31.3, 28.9, 22.1, 13.9 ppm. MS (EI):
228.1362; found 228.1366.
m/z (%) = 346 (25.17) [M]+, 287 (100). IR (neat): ν = 2955, 2871,
˜
Dimethyl 2-[(E)-Tetradec-5-en-6-yl]malonate (2ha): Following the
general procedure for 2ab, the reaction of 1h (53.9 mg, 0.20 mmol)
and nBuLi (1.6 m in hexane, 0.31 mL, 0.50 mmol) in THF (2 mL)
gave the crude product (petroleum ether/ethyl acetate, 20:1) af-
1738, 1512, 1461, 1434, 1403, 1383, 1364, 1311, 1269, 1237, 1196,
1085, 1025 cm–1. HRMS: calcd. for C21H30O4 [M]+ 346.2144;
found 346.2145.
Dimethyl 2-[(Z)-1-(4-tert-Butylphenyl)prop-1-enyl]malonate (2eb): forded 2ha (28.5 mg, 43%) as a liquid. 1H NMR (300 MHz,
Following the general procedure for 2ab, the reaction of 1e
CDCl3): δ = 5.41 (t, J = 7.2 Hz, 1 H, C=CCH), 4.02 (s, 1 H, CH),
(57.9 mg, 0.20 mmol) and MeLi (3.0 m in diethoxymethane, 3.72 (s, 6 H, 2 OCH3), 2.16–2.01 (m, 4 H, 2 C=CCH2), 1.39–1.21
0.17 mL, 0.50 mmol) in THF (2 mL) gave the crude product. Puri-
fication by chromatography (petroleum ether/ethyl acetate, 6:1) af-
forded 2eb (25.7 mg, 42%) as a liquid. 1H NMR (300 MHz,
CDCl3): δ = 7.37–7.31 (m, 2 H, Ar), 7.17–7.10 (m, 2 H, Ar), 5.85
(q, J = 6.9 Hz, 1 H, C=CCH), 4.39 (s, 1 H, CH), 3.72 (s, 6 H, 2
OCH3), 1.65 (d, J = 6.6 Hz, 3 H, CH3), 1.31 (s, 9 H, 3 CH3) ppm.
13C NMR (75 MHz, CDCl3): δ = 168.8, 149.9, 135.9, 133.2, 128.4,
127.8, 125.0, 59.4, 52.6, 34.5, 31.3, 15.1 ppm. MS (EI): m/z (%) =
(m, 16 H, 8 CH2), 0.92–0.83 (m, 6 H, 2 CH3) ppm. 13C NMR
(75 MHz, CDCl3): δ = 169.1, 132.1, 131.6, 58.1, 52.4, 31.8, 31.6,
30.6, 29.6, 29.4, 29.2, 28.4, 27.7, 22.6, 22.3, 14.1, 13.9 ppm. MS
(EI): m/z (%) = 326 (6.71) [M]+, 267 (100). IR (neat): ν = 2955,
˜
2926, 2856, 1740, 1465, 1435, 1379, 1313, 1196, 1146, 1028 cm–1.
HRMS: calcd for C19H34O4 [M]+ 326.2457; found 326.2459.
Deuterium-Labeling Experiments
304 (12.76) [M]+, 245 (100). IR (neat): ν = 2954, 2868, 1737, 1512,
Preparation of Dideuterated Dimethyl 2-[(Z)-1-Phenylhex-1-en-1-yl-
]malonate (2aa-d2): To a dried Schlenk tube were added 1a
(92.2 mg, 0.40 mmol) and THF (3 mL) under nitrogen. After the
solution was cooled to –60 °C, nBuLi (1.6 m in hexane, 0.63 mL,
1.0 mmol) was added through a syringe. The resulting mixture was
stirred at –60 °C for 2.5 h, which was followed by the dropwise
addition of a solution of AcOD (244.7 mg, 4.0 mmol) in THF
(1.0 mL). The resulting mixture was stirred at –60 °C for an ad-
ditional 40 min. Then, D2O (3 mL) was added, and the resulting
mixture was stirred for 10 min at –60 °C and then an additional
10 min at room temp. The reaction was stopped, and the organic
layer was separated. The water phase was extracted with Et2O
(2ϫ5 mL). The combined organic layers were evaporated immedi-
ately to avoid the exchange of the D atom at the sp3-hybridized
˜
1460, 1434, 1364, 1311, 1270, 1232, 1194, 1146, 1024 cm–1. HRMS:
calcd. for C18H24O4 [M]+ 304.1675; found 304.1673.
Dimethyl 2-[(Z)-1-(4-Chlorophenyl)hex-1-enyl]malonate (2fa): Fol-
lowing the general procedure for 2ab, the reaction of 1f (53.4 mg,
0.20 mmol) and nBuLi (1.6 m in hexane, 0.31 mL, 0.50 mmol) in
THF (2 mL) gave the crude product. Purification by chromatog-
raphy (petroleum ether/ethyl acetate, 20:1) afforded 2fa (38.9 mg,
60%) as a liquid. 1H NMR (300 MHz, CDCl3): δ = 7.30 (d, J =
8.4 Hz, 2 H, Ar), 7.15 (d, J = 8.1 Hz, 2 H, Ar), 5.77 (t, J = 7.4 Hz,
1 H, C=CCH), 4.34 (s, 1 H, CH), 3.71 (s, 6 H, 2 OCH3), 1.95 (q,
J = 7.2 Hz, 2 H, C=CCH2), 1.39–1.16 (m, 4 H, 2 CH2), 0.81 (t, J
= 7.1 Hz, 3 H, CH3) ppm. 13C NMR (75 MHz, CDCl3): δ = 168.4,
137.4, 135.1, 133.1, 131.4, 130.3, 128.3, 59.4, 52.5, 31.4, 28.8, 22.1,
13.8 ppm. MS (EI): m/z (%) = 326 (3.97) [M(37Cl)]+, 324 (11.50)
1
carbon with an H atom from the surroundings. H NMR analysis
of the crude product showed the occurrence of 97% and 71% deu-
teration at the sp3- and sp2-hybridized carbons, respectively.
Chromatography on silica gel (petroleum ether/ethyl acetate, 20:1)
afforded 2aa-d2 (88.0 mg, 76% yield, 32% and 63% deuteration at
sp3- and sp2-hybridized carbons, respectively) as a liquid. 1H NMR
(300 MHz, CDCl3, for 2aa-d2): δ = 7.36–7.17 (m, 5 H, Ar), 3.71 (s,
[M(35Cl)]+, 221 (100). IR (neat): ν = 2956, 2864, 1741, 1491, 1437,
˜
1388, 1311, 1198, 1152, 1091, 1018 cm–1. HRMS: calcd. for
C17H21O435Cl [M]+ 324.1128; found 324.1128.
Dimethyl 2-[(Z)-1-(4-Chlorophenyl)prop-1-en-1-yl]malonate (2fb):
Following the general procedure for 2ab, the reaction of 1f
(53.0 mg, 0.20 mmol) and MeLi (3.0 m in diethoxymethane, 6 H, 2 OCH3), 1.98 (t, J = 6.3 Hz, 2 H, C=CCH2), 1.40–1.16 (m,
0.17 mL, 0.50 mmol) in THF (2 mL) gave the crude product. Puri-
fication by chromatography (petroleum ether/ethyl acetate, 10:1) af-
forded 2fb (35.6 mg, 63%) as a liquid. 1H NMR (300 MHz,
CDCl3): δ = 7.33–7.27 (m, 2 H, Ar), 7.18–7.12 (m, 2 H, Ar), 5.88
(q, J = 6.9 Hz, 1 H, C=CCH), 4.34 (s, 1 H, CH), 3.70 (s, 6 H, 2
OCH3), 1.60 (d, J = 7.2 Hz, 3 H, CH3) ppm. 13C NMR (75 MHz,
CDCl3): δ = 168.4, 137.0, 133.1, 132.4, 130.4, 129.1, 128.4, 59.4,
52.6, 15.0 ppm. MS (EI): m/z (%) = 284 (6.71) [M(37Cl)]+, 282
4 H, 2 CH2), 0.81 (t, J = 6.9 Hz, 3 H, CH3) ppm. 1H NMR
(300 MHz, CDCl3, discernible signals for 2aa): δ = 5.76 (t, J =
7.4 Hz, 0.37 H, C=CH), 4.37 (s, 0.68 H, CH) ppm. MS (EI): m/z
(%) = 292 (10.11) [M]+, 189 (100). IR (neat): ν = 2955, 1737, 1493,
˜
1435, 1315, 1256, 1197, 1149, 1074, 1025 cm–1. HRMS: calcd. for
C17H20D2O4 [M]+ 292.1644; found 292.1644.
Monodeuterated Dimethyl 2-[(Z)-1-Phenylhex-1-en-1-yl]malonate
(2aa-d): To a dried Schlenk tube were added 1a-d (46.7 mg,
0.20 mmol) and THF (2 mL) under Ar. After the solution was co-
oled to –60 °C, nBuLi (1.6 m in hexane, 0.31 mL, 0.50 mmol) was
added through a syringe. The mixture was stirred at –60 °C for
2.0 h and was monitored by TLC (petroleum ether/ethyl acetate,
10:1). The reaction mixture was then quenched with a saturated
aqueous NH4Cl solution (0.5 mL). Water (10 mL) was added, and
the mixture was extracted with Et2O (3ϫ10 mL). Filtration, evapo-
ration, and analysis by 1H NMR showed the occurrence of 17%
(18.51) [M(35Cl)]+, 223 (100), 163 (100). IR (neat): ν = 2997, 2954,
˜
2858, 1737, 1491, 1435, 1394, 1367, 1313, 1233, 1196, 1150, 1090,
1016 cm–1. HRMS: calcd. for C14H15O435Cl [M]+ 282.0659; found
282.0658.
Dimethyl 2-[(E)-Hept-2-en-3-yl]malonate (2gb): Following the gene-
ral procedure for 2ab, the reaction of 1g (43.4 mg, 0.20 mmol) and
MeLi (3.0 m in diethoxymethane, 0.17 mL, 0.50 mmol) in THF
(2 mL) gave the crude product. Purification by chromatography
3038
www.eurjoc.org
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2013, 3033–3040

Ring-Opening Reactions of Cyclopropenedicarboxylates
deuteration at the sp2-hybridized carbon. Chromatography on silica
(46.4 mg, 0.20 mmol) in THF (1 mL) was added through a syringe.
The mixture was stirred at 0 °C for 6.0 h and was monitored by
TLC (petroleum ether/ethyl acetate, 5:1). The reaction mixture was
gel (petroleum ether/ethyl acetate, 15:1) afforded 2aa-d (40.8 mg,
70% yield, 18% deuteration at the sp2-hybridized carbon) as a li-
1
quid. H NMR (300 MHz, CDCl3, for 2aa-d): δ = 7.37–7.16 (m, 5 then quenched with a saturated aqueous NH4Cl solution (1.0 mL).
H, Ar), 4.38 (s, 1 H, CH), 3.71 (s, 6 H, 2 OCH3), 1.99 (q, J =
Water (10 mL) was added, and the resulting mixture was extracted
7.0 Hz, 2 H, C=CCH2), 1.40–1.16 (m, 4 H, 2 CH2), 0.81 (t, J = with Et2O (3ϫ10 mL). The combined organic layers were washed
1
7.1 Hz, 3 H, CH3) ppm. H NMR (300 MHz, CDCl3, discernible
with water (10 mL) and dried with anhydrous Na2SO4. Filtration,
evaporation, and chromatography on silica gel (petroleum ether/
ethyl acetate, 15:1) afforded 2af[4] (23.6 mg, 38%) as a liquid. 1H
NMR (300 MHz, CDCl3): δ = 7.35–7.21 (m, 5 H, Ar), 7.12–7.04
signal for 2aa): δ = 5.76 (t, J = 7.4 Hz, 0.82 H, C=CH) ppm. MS
(EI): m/z (%) = 291 (3.63) [M]+, 187 (100). IR (neat): ν = 2955,
˜
2930, 2858, 1737, 1493, 1435, 1313, 1256, 1196, 1149, 1074,
1024 cm–1. HRMS: calcd. for C17H21DO4 [M]+ 291.1581; found (m, 3 H, Ar), 6.99–6.91 (m, 2 H, Ar), 6.72 (s, 1 H, C=CH), 4.53
291.1580.
(s, 1 H, CH), 3.74 (s, 6 H, 2 OCH3) ppm. 13C NMR (75 MHz,
CDCl3): δ = 168.3, 139.4, 136.0, 133.6, 131.9, 129.4, 129.0, 128.6,
127.8, 127.7, 127.2, 60.4, 52.7 ppm. MS (EI): m/z (%) = 310 (20.96)
Monodeuterated Dimethyl 2-[(Z)-1-Phenylhex-1-en-1-yl]malonate
(2aa-dЈ): To a dried Schlenk tube were added 1a (57.4 mg,
0.20 mmol) and THF (2 mL) under Ar. After the solution was
cooled to –60 °C, nBuLi (1.6 m in hexane, 0.31 mL, 0.5 mmol) was
added through a syringe. The resulting mixture was stirred at
–60 °C for 2.0 h, which was followed by the dropwise addition of
a solution of AcOD (122.3 mg, 2.0 mmol) in THF (0.5 mL). The
resulting mixture was stirred at –60 °C for another 30 min. Then,
D2O (2 mL) was added, and the resulting mixture was stirred at
–60 °C for 10 min and at room temperature for another 60 min.
The reaction was stopped, and the solution was extracted with
Et2O (2ϫ5 mL). The combined organic layers were concentrated
immediately to avoid the exchange of the D atom at the sp3-hy-
[M]+, 191 (100). IR (neat): ν = 2953, 1737, 1600, 1495, 1435, 1312,
˜
1250, 1194, 1150, 1067, 1030 cm–1.
Tetramethyl
(E)-2-Benzylidene-5-phenylpent-4-yne-1,1,3,3-tetra-
carboxylate (4): To a dried Schlenk tube were added 1a (70.3 mg,
0.30 mmol) and THF (2 mL) under Ar. PhZnBr (0.5 m in THF,
3.0 mL, 1.5 mmol) was added through a syringe. The mixture was
stirred at room temp. for 9.0 h and was monitored by TLC (petro-
leum ether/ethyl acetate, 5:1). The reaction mixture was then
quenched with a saturated aqueous NH4Cl solution (0.5 mL).
Water (10 mL) was added, and the mixture was extracted with Et2O
(3ϫ5 mL). The combined organic layers were dried with anhy-
drous Na2SO4. Filtration, evaporation, and chromatography on sil-
ica gel (petroleum ether/ethyl acetate, 7:1) followed by recrystalli-
zation (petroleum ether/diethyl ether) afforded 4 (43.2 mg, 61%) as
1
bridized carbon atom with the H atom from the surroundings. H
NMR analysis of the crude product showed 94% deuteration at
the sp3-hybridized carbon atom. Chromatography on silica gel (pe-
troleum ether/ethyl acetate = 10:1) afforded 2aa-dЈ (51.5 mg, 89%
yield, 43% deuteration at sp3-hybridized carbon atom) as a liquid.
1H NMR (300 MHz, CDCl3, for 2aa-dЈ): δ = 7.37–7.17 (m, 5 H,
Ar-H), 5.76 (s, 1 H, J = 7.5 Hz, 1 H, C=C–H), 3.72 (s, 6 H, 2
OCH3), 1.99 (q, J = 7.3 Hz, 2 H, C=C–CH2), 1.40–1.176 (m, 4 H,
1
a solid; m.p. 103–104 °C (petroleum ether/diethyl ether). H NMR
(300 MHz, CDCl3): δ = 7.53–7.47 (m, 2 H, Ar), 7.44–7.38 (m, 3 H,
Ar), 7.36–7.27 (m, 6 H, Ar and C=CH), 4.75 (s, 1 H, CH), 3.87 (s,
6 H, 2 OCH3), 3.49 (s, 6 H, 2 OCH3) ppm. 13C NMR (75 MHz,
CDCl3): δ = 167.9, 167.5, 138.3, 135.3, 131.9, 128.8, 128.5, 128.2,
128.0, 127.9, 127.6, 122.0, 89.2, 82.5, 61.8, 53.9, 53.0, 52.4 ppm.
1
2 CH2), 0.81 (t, J = 7.2 Hz, 3 H, CH3) ppm. H NMR (300 MHz,
MS (EI): m/z (%) = 464 (2.41) [M]+, 405 (100). IR (neat): ν =
˜
CDCl3, discernible signal for 2aa): δ = 4.38 (s, 0.57 H, CH) ppm.
MS (EI): m/z (%) = 291 (7.74) [M]+, 187 (100). IR (neat) ν = 2955,
2954, 2923, 2852, 1758, 1730, 1491, 1435, 1372, 1292, 1230, 1153,
1049 cm–1. C26H24O8 (464.47): calcd. C 67.23, H 5.21; found C
67.24, H 5.09.
˜
2855, 1737, 1494, 1435, 1315, 1261, 1148, 1073, 1023 cm–1. HRMS:
calcd. for C17H21DO4 [M]+ 291.1581; found 291.1583.
Monodeuterated Tetramethyl (E)-2-Benzylidene-5-phenylpent-4-yne-
1,1,3,3-tetracarboxylate (4-d): To a dried Schlenk tube were added
1a (70.1 mg, 0.30 mmol) and THF (2 mL) under nitrogen. PhZnBr
(0.5 m in THF, 3.0 mL, 1.5 mmol) was added through a syringe.
The mixture was stirred at room temp. for 10.0 h. A solution of
AcOD (183.8 mg, 3.0 mmol) in THF (0.5 mL) was added dropwise,
and the resulting mixture was stirred at room temp. for an ad-
ditional 0.5 h. D2O (5 mL) was added, and the mixture was stirred
at room temp. for 10 min. The mixture was then extracted with
Et2O (2ϫ10 mL). The combined organic layers were evaporated
immediately to avoid the exchange of the D atom at the sp3-hy-
Ring-Opening Reactions of Cyclopropenes with Organozincs
Dimethyl 2-[(Z)-1-Phenylbut-1-en-1-yl]malonate (2ae): To a dried
Schlenk tube were added 1a (46.5 mg, 0.20 mmol) and THF (2 mL)
under Ar. After the solution was cooled to 0 °C, Et2Zn (1.5 m in
toluene, 0.40 mL, 0.60 mmol) was added through a syringe. The
mixture was stirred at 0 °C for 10.0 h and was monitored by TLC
(petroleum ether/ethyl acetate, 10:1). The reaction mixture was then
quenched with a saturated aqueous NH4Cl solution (1.0 mL).
Water (10 mL) and HCl (1 m solution, 1 mL) were added, and the
resulting mixture was extracted with Et2O (3ϫ10 mL). The com-
bined organic layers were washed sequentially with brine (10 mL)
and water (10 mL) and then dried with anhydrous Na2SO4. Fil-
tration, evaporation, and chromatography on silica gel (petroleum
ether/ethyl acetate, 20:1) afforded 2ae[4] (15.7 mg, 30%) as a liquid.
1H NMR (300 MHz, CDCl3): δ = 7.37–7.17 (m, 5 H, Ar), 5.75 (t,
J = 7.4 Hz, 1 H, C=CH), 4.38 (s, 1 H, CH), 3.71 (s, 6 H, 2 OCH3),
2.05–1.92 (m, 2 H, CH2), 0.95 (t, J = 7.4 Hz, 3 H, CH3) ppm. 13C
NMR (75 MHz, CDCl3): δ = 168.6, 139.1, 135.5, 132.1, 128.8,
128.1, 127.2, 59.5, 52.5, 22.6, 13.9 ppm. MS (EI): m/z (%) = 262
1
bridized carbon with an H atom from the surroundings. H NMR
analysis of the crude product showed an occurrence of 84% deuter-
ation at the sp3-hybridized carbon. Chromatography on silica gel
(petroleum ether/ethyl acetate, 8:1) afforded 4-d (31.1 mg, 44%
yield, 30% deuteration at sp3-hybridized carbon) as a solid. 1H
NMR (300 MHz, CDCl3, for 4-d): δ = 7.54–7.47 (m, 2 H, Ar),
7.44–7.38 (m, 3 H, Ar), 7.36–7.27 (m, 6 H, Ar and C=CH), 3.87
(s, 6 H, 2 OCH3), 3.50 (s, 6 H, 2 OCH3) ppm. 1H NMR (300 MHz,
CDCl3, discernible signal for 4): 4.75 (s, 0.7 H, CH) ppm. MS (EI):
(10.25) [M]+, 203 (100). IR (neat): ν = 2956, 1736, 1683, 1600, 1575,
m/z (%) = 465 (3.07) [M]+, 59 (100). IR (neat): ν = 2955, 1718,
˜
˜
1494, 1435, 1385, 1313, 1194, 1149, 1072, 1030 cm–1.
1562, 1493, 1436, 1259, 1068 cm–1. HRMS: calcd. for C26H23DO8
[M]+ 465.1534; found 465.1535.
Dimethyl 2-[(Z)-1,2-Diphenylvinyl]malonate (2af): To
a dried
Schlenk tube were added Ph2Zn (130.7 mg, 0.6 mmol) and THF
(2 mL) under Ar. After the solution was cooled to 0 °C, 1a
Supporting Information (see footnote on the first page of this arti-
1
cle): Copies of the H and 13C NMR spectra of the products.
Eur. J. Org. Chem. 2013, 3033–3040
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3039

Y. Liu, Q. Yu, S. Ma
FULL PAPER
ucts, see: Y. Wang, E. A. F. Fordyce, F. Y. Chen, H. W. Lam,
Angew. Chem. 2008, 120, 7460; Angew. Chem. Int. Ed. 2008,
47, 7350–7353.
Acknowledgments
Financial support from the National Natural Science Foundation
of China (NSFC) (grant number 21232006) and the State Basic
Research & Development Program of China (grant number
2009CB825300) is greatly appreciated. The authors thank Mr.
Binjie Guo for reproducing the results of the preparation of 2ad,
2da, and 2gb.
[6] a) S. Ma, J. Zhang, Y. Cai, L. Lu, J. Am. Chem. Soc. 2003,
125, 13954–13955; b) Y. Wang, H. Lam, J. Org. Chem. 2009,
74, 1353–1355.
[7] For some recent reports about the deprotonation of cyclo-
propenes, see: a) M. Nakamura, H. Isobe, E. Nakamura,
Chem. Rev. 2003, 103, 1295–1326, and references cited therein;
b) I. Zrinski, G. Gadanji, M. Eckert-Maksic, New J. Chem.
2003, 27, 1270–1276; c) I. Zrinski, M. Eckert-Maksic, Synth.
Commun. 2003, 33, 4071–4077; d) I. Zrinski, N. Novak-Coum-
bassa, M. Eckert-Maksic, Organometallics 2004, 23, 2806–
2809; e) L. Liao, N. Yan, J. M. Fox, Org. Lett. 2004, 6, 4937–
4939; f) L. A. Fisher, J. M. Fox, J. Org. Chem. 2008, 73, 8474–
8478; g) R. Kim, W. M. Sherrill, M. Rubin, Tetrahedron 2010,
66, 4947–4953.
[1]
[2]
a) M. Rubin, M. Rubina, V. Gevorgyan, Synthesis 2006, 8,
1221–1245, and references cited therein; b) Z.-B. Zhu, Y. Wei,
M. Shi, Chem. Soc. Rev. 2011, 40, 5534–5563.
a) R. D. Bach, O. Dmitrenko, J. Am. Chem. Soc. 2006, 128,
4598–4611; b) A. Fattahi, R. E. McCarthy, M. R. Ahmad,
S. R. Kass, J. Am. Chem. Soc. 2003, 125, 11746–11750.
[8] Crystal structure data for 4: C26H24O8, M = 464.45 gmo1–1,
¯
[3] For recent reviews, see: a) M. S. Baird, Chem. Rev. 2003, 103,
1271–1294; b) J. M. Fox, N. Yan, Curr. Org. Chem. 2005, 9,
719–732; c) M. Rubin, M. Rubina, V. Gevorgyan, Chem. Rev.
2007, 107, 3117–3179; d) I. Marek, S. Simman, A. Masarwa,
Angew. Chem. 2007, 119, 7508; Angew. Chem. Int. Ed. 2007, 46,
7364–7376; for selected examples of a ring-retentive addition of
organometallic reagents to cyclopropene, see: e) X. Liu, J. M.
Fox, J. Am. Chem. Soc. 2006, 128, 5600–5601; f) X. Xie, Z.
Yang, J. M. Fox, J. Org. Chem. 2010, 75, 3847–3850; g) V. Tar-
wade, X. Liu, N. Yan, J. M. Fox, J. Am. Chem. Soc. 2009, 131,
5382–5383; h) K. Krämer, P. Leong, M. Lautens, Org. Lett.
2011, 13, 819–821.
triclinic, space group P1, final R indices [I Ͼ 2σ(I)], R1 =
0.0396, wR2 = 0.1048, R indices (all data) R1 = 0.0481, wR2
= 0.1130, a = 9.9719(4) Å, b = 11.1424(5) Å, c = 11.5735(5) Å,
α = 77.2990(10)°, β = 71.4190(10)°, γ = 81.0920(10)°, V =
1184.08(9) Å3, T = 296(2) K, Z = 2, reflections collected/
unique: 13797/4143 (Rint = 0.0264), number of observations
[I Ͼ 2σ(I)] 3450, parameters: 307. CCDC-908535 contains the
supplementary crystallographic data for compound 4. These
data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
[9] J. Chen, S. Ma, Chem. Asian J. 2010, 5, 2415–2421.
[10] S. Chen, J. Ren, Z. Wang, Tetrahedron 2009, 65, 9146–9151.
Received: November 26, 2012
[4] Y. Liu, S. Ma, Chem. Sci. 2011, 2, 811–814.
[5] For an iron-catalyzed ring-opening reaction of cyclopropenyl
carboxylates with organoaluminums leading to the same prod-
Published Online: April 3, 2013
3040
www.eurjoc.org
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2013, 3033–3040