Metal-free domino Cloke-Wilson rearrangement-hydration-dimerization of cyclopropane carbaldehydes: A facile access to oxybis(2-aryltetrahydrofuran) derivatives

Article abstract of DOI:10.1016/j.tet.2020.131080

In this work, we have demonstrated a metal-free transformation of cyclopropane carbaldehydes to oxybis(2-aryltetrahydrofuran) derivatives via a domino Cloke-Wilson rearrangement-hydration-dimerization sequence. Commercially inexpensive p-toluene sulfonic acid (PTSA) was used as a Br?nsted acid catalyst, and reactions were conducted in an open-flask. Detection of reaction intermediates were carried to get an insight into the reaction pathway.

Full text of DOI:10.1016/j.tet.2020.131080

Tetrahedron xxx (xxxx) xxx
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Metal-free domino Cloke-Wilson rearrangement-hydration-
dimerization of cyclopropane carbaldehydes: A facile access to
oxybis(2-aryltetrahydrofuran) derivatives
Raghunath Dey 1, Shruti Rajput 1, Prabal Banerjee*
Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab, 140001, India
a r t i c l e i n f o
a b s t r a c t
Article history:
In this work, we have demonstrated a metal-free transformation of cyclopropane carbaldehydes to
oxybis(2-aryltetrahydrofuran) derivatives via a domino Cloke-Wilson rearrangement-hydration-dimer-
ization sequence. Commercially inexpensive p-toluene sulfonic acid (PTSA) was used as a Brønsted acid
catalyst, and reactions were conducted in an open-flask. Detection of reaction intermediates were carried
to get an insight into the reaction pathway.
Received 28 January 2020
Received in revised form
14 February 2020
Accepted 22 February 2020
Available online xxx
© 2020 Elsevier Ltd. All rights reserved.
Keywords:
Cyclopropanes
Metal-free
PTSA
Domino reaction
Oxybis(2-aryltetrahydrofuran) derivatives
1. Introduction
been realized as the potential synthetic tool to generate molecular
complexity. Some of them also implicated to synthesize complex
Construction of invaluable molecular scaffold from a readily
available starting material always remains a key interest in syn-
thetic organic chemistry [1a]. More importantly, designing the
method to access the target in a cheaper, eco-friendly, and user-
friendly manner is highly appealing [1b]. From that perspective,
domino strategy has evolved as a convenient approach towards the
development of the sustainable synthetic route [1c].
In this notion, due to the ease of preparation and foreseeable
reactivity, donor-acceptor cyclopropane has been utilized as a
venerable three carbon synthon in various synthetic trans-
formation (Scheme 1) [2e5]. In the presence of a nucleophile, it
undergoes a homo Michael addition to deliver ring-opened/1,3-
bifunctionalized products. It can participate in annulation re-
actions with different polar species to render a wide range of het-
ero- and carbocyclic compounds. Over the last few decades, the
annulation of donor-acceptor cyclopropane has been widely
explored with various carbonyl compounds, nitriles, imines, al-
kenes, azides, ylides, nitrones, etc. Soon after, these methods have
natural products [3]. Recently, we utilized various annulation of
donor-acceptor cyclopropane to synthesize diverse nitrogen het-
erocycles like tetrahydropyridines, hexahydropyrrolo[1,2 b]pyr-
idazines, 2H furo[2,3c]pyrroles, and others [4]. Apart from these
reactions of donor-acceptor cyclopropane, because of its inherent
reactivity, it voluntarily takes part in certain structural changes like
dimerization and rearrangement [5]. Research group of Tomilov,
Trushkov, Budynina, and others utilized dimerization of cyclopro-
pane to construct diverse heterocycles and carbocycles. In a series
of reports, very elegantly, they have explored an array of dimer-
ization of donor-acceptor cyclopropanes. These investigations gave
us the sense that, under proper kinetic trigger, cyclopropane itself is
capable of converting into many valuable scaffolds.
However, most of the reported dimerizations are metal cata-
lyzed process. These metal catalyzed reactions are associated with
several drawbacks like sometimes the effective catalyst is toxic,
often moisture sensitivity of the Lewis acid creates difficulties in
handling, many times Lewis acids are expansive [6].
Therefore, recently, the exploration of reactivity of donor-
acceptor cyclopropane under metal-free regime has been attrac-
ted enormous attention. One remarkable approach towards metal-
free activation of donor-acceptor cyclopropane is the secondary
* Corresponding author.
E-mail address: prabal@iitrpr.ac.in (P. Banerjee).
1
These two authors contributed equally.
https://doi.org/10.1016/j.tet.2020.131080
0040-4020/© 2020 Elsevier Ltd. All rights reserved.
Please cite this article as: R. Dey et al., Metal-free domino Cloke-Wilson rearrangement-hydration-dimerization of cyclopropane carbaldehydes:
A facile access to oxybis(2-aryltetrahydrofuran) derivatives, Tetrahedron, https://doi.org/10.1016/j.tet.2020.131080

2
R. Dey et al. / Tetrahedron xxx (xxxx) xxx
analysis [10] whereas, the relative stereochemistry of 2a′ and 2a’’’
was determined by 2D NOE-NMR analysis (Fig. 1, also see the ESI).
In order to find a similar sulfonic acid catalyst which can provide
the higher yield, camphor sulfonic acid was utilized in the designed
reaction. But this attempt also remained unfruitful. Hydrochloric
acid as an inorganic Brønsted acid was also exploited in the titled
reaction, which in turn gave the desired product with a lower yield.
These outcomes drove us to select p-toluene sulfonic acid as the
best catalyst for this transformation. Taking p-toluene sulfonic acid
as the optimized catalyst, we further screened the reaction with
various solvents. In more polar solvent like dimethyl sulfoxide
(DMSO) and N,N-dimethylformamide (DMF), the substrate
remained unreacted. Also, in coordinating solvent like tetrahydro-
furan (THF) no desired product formation was noticed. Alcoholic
solvents like methanol and ethanol were also unable to deliver the
expected product. After these studies, it was clear that DCM is the
best solvent for this transformation. In order to probe the equitable
mol % of the catalyst, the model reaction was conducted in the
presence of different mol % of PTSA. 10 mol % and 20 mol % catalyst
provided similar outcomes. Whereas, higher loading of the catalyst
from 20 mol % to 50 mol % led to make the reaction messier.
Consequently, from these optimization studies, 10 mol % PTSA in
dichloromethane came out as an optimized reaction condition.
With this optimized reaction condition in hand, the scopes and
limitations of this reaction with respect to various cyclopropane
carbaldehydes were explored (Table 2). In the case of cyclopropane
carbaldehyde containing an electronically rich aryl substituent like
methylenedioxyphenyl (1b), the product (2b) was obtained in a low
yield. The reason behind low yield is the high electron donating
ability of the methylenedioxyphenyl substituent makes the corre-
sponding cyclopropane susceptible to decomposition in the reac-
tion medium. However, the 4-benzyloxyphenyl-substituted
cyclopropane carbaldehyde (1c) took part in the reaction to render
the corresponding product (2c) with an improved yield. After this
observation we wanted to see whether the yield could be enhanced
by using little less activated substrate like tolyl- (1d) and 4-
isopropylphenyl- (1e) substituted cyclopropane carbaldehyde.
Gratifyingly, in both the cases we attained the desired products (2d
and 2e respectively) with better yield although they took relatively
long time to completely convert into the corresponding products.
These observations made us optimistic to see whether the yield of
the reaction can further be increased by using much less activated
substrate like phenyl cyclopropane carbaldehyde (1f). Neverthe-
less, in this case, we ended up with a reduced yield along with a
longer reaction time. Also, the 4-fluorophenyl cyclopropane car-
baldehyde (1g) provided similar yield of the desired products, as
obtained with the phenyl cyclopropane carbaldehyde. Noticeably,
when cyclopropane carbaldehyde (1h) bearing 4-chlorophenyl
substituent could not able to deliver the desired product 2h. To
check the influence of substitution at the 3-position of aryl ring, we
exploited 3-bromophenyl cyclopropane carbaldehyde (1i) in the
designed reaction, but no desired product (2i) was attained. 3-
Methoxyphenyl cyclopropane carbaldehyde (1j) was also failed to
deliver the expected product (2j). Cyclopropane carbaldehyde
containing naphthyl substituent was also exploited in the model
Scheme 1. Reactions of donor-acceptor cyclopropane via Lewis acid activation [2e5].
amine organocatalytic activation, reported by Werz and others to
construct 1,3-bifunctionalized products [7]. Another notable
approach for the same is the Brønsted acid organocatalytic activa-
tion [8]. Very recently, this domain has been enlightened with the
commendable work by Moran,[8a,8b] Kerr, [8c] and Lopez [8d].
They demonstrated the hydrogen bonding assisted nucleophilic
ring-opening of donor-acceptor cyclopropane (Scheme 2A). Paral-
lelly, we also took the same initiative to explore the mentioned
chemistry and very recently unfolded a metal-free ring-opening
reaction of cyclopropane carbaldehydes and N-benzylanilines to-
wards synthesis of amine-functionalized butanal derivatives [8e].
The attractive part of this work was that the reaction worked in
open-flask and dram-grade solvent (dichloromethane). This suc-
cess tempted us to know how cyclopropane carbaldehyde will
behave in the absence of another reactive partner but under the
same activation. To our delight, we found that, in the presence of
Brønsted acid, cyclopropane carbaldehyde itself engaged in a
domino Cloke-Wilson rearrangement-hydration-dimerization
sequence to render oxybis(2-aryltetrahydrofuran) derivatives
(Scheme 2B).
2. Results and discussion
In order to optimize the reaction conditions, at the outset, 4-
methoxyphenyl cyclopropane carbaldehyde (1a) was picked as a
model substrate. 1a was treated with various Brønsted acids, as
shown in Table 1. Our initial trials with anisic acid and benzoic acid
were not successful. Afterwards we moved to a little stronger
Brønsted acid like trifluoroacetic acid. In this case, also the sub-
strate remained unreacted. However, stronger Brønsted acid like p-
toluene sulfonic acid was able to catalyze the process to provide the
expected product as a mixture of three diastereomers in an
acceptable yield. These diastereomers are respectively 2a’ (both the
tetrahydrofuran moiety having cis-configuration), 2a’’ (one tetra-
hydrofuran moiety having cis- and another tetrahydrofuran moiety
having trans-configuration) and 2a’’’ (both the tetrahydrofuran
moiety having trans-configuration) (Table 1). The relative stereo-
chemistry of 2a’’ was confirmed by single crystal X-ray diffraction
reaction. Among
baldehyde, -naphthyl cyclopropane carbaldehyde (1k) delivered
the product 2k with better yield compared to the -substituted one
(1l). Not only the yield but also the rate of the reaction was faster for
the -naphthyl cyclopropane carbaldehyde than the -naphthyl
a- and b-naphthyl substituted cyclopropane car-
b
a
b
a
cyclopropane carbaldehyde. This may be because of the steric effect
of the ortho-substituent leads to lower the yield and the reaction
rate. Stimulated by these observations, to check the effect of ortho-
substituent in further detail, we employed the mesityl cyclopro-
pane carbaldehyde (1m) in the titled reaction, which could not able
Scheme 2. Reactions of donor-acceptor cyclopropane via Brønsted acid activation [8].
Please cite this article as: R. Dey et al., Metal-free domino Cloke-Wilson rearrangement-hydration-dimerization of cyclopropane carbaldehydes:
A facile access to oxybis(2-aryltetrahydrofuran) derivatives, Tetrahedron, https://doi.org/10.1016/j.tet.2020.131080

R. Dey et al. / Tetrahedron xxx (xxxx) xxx
3
Table 1
Optimization of the reaction conditions.a
sl. no.
Brønsted acid
solvent
Brønsted acid (mol %)
reaction time (h)
yield (%)b
dr (2a’:2a’’:2a’’’)
1.
2.
3.
4.
5.
6.
7.
8.
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DMSO
DMF
THF
EtOAc
MeOH
EtOH
DCM
DCM
24
24
24
24
24
2.5
3.5
02
0.7
24
24
24
24
24
24
03
1.5
n.r.c
n.r.c
n.r.c
n.r.c
n.r.c
45
Anisic acid
Benzoic acid
Trifluoroacetic acid
Binol
20
20
20
20
20
20
20
20
20
20
20
20
20
10
50
PTSA
41:45:14
36:46:18
Camphorsulfonic acid
Triflic acid
Hydrochloric acid
PTSA
PTSA
PTSA
PTSA
PTSA
PTSA
PTSA
41
c.m.e
38
9.
30:48:22
10.
11.
12.
13.
14.
15.
16.
17.
n.r.c
n.r.c
n.p.d
n.p.d
n.p.d
n.p.d
47
41:45:14
37:45:18
PTSA
38
a
Reactions were carried out with 1 equiv (0.284 mmol) of 1a.
Isolated overall yield of three diastereomers (2a’þ2a’’þ2a’’’).
n.r. ¼ no reaction (substrate remain as such).
n.p. ¼ no desired product formation.
b
c
d
e
c.m. ¼ complex reaction mixture.
and D’ (via pathway m’). Once again, the generated lactol inter-
mediate D and D′ undergoes an addition reaction with another
molecule of oxocarbenium ion C. Here also, the addition from two
alternative faces (pathway n and n’ for lactol D, pathway o, and o’
for lactol D′) delivered the final product in the form of two di-
astereomers for each intermediate. Therefore, total four di-
astereomers (2′,2000’ from lactol D and 2’’, 2000 from lactol D′)
supposed to be obtained. However, two diastereomers, namely 2’’
and 2000’ become identical because of their stereochemical sym-
metry. Therefore, eventually three diastereomers (2′, 2’’ and 2000) are
obtained.
In order to get more insight about the complete reaction
pathway, we tried to detect the reaction intermediates. Mass of
intermediate B and C were found in the GC-MS analysis of the
incomplete crude reaction mixture (Fig. 2, and also see the ESI). But,
in GC-MS analysis, we could not be able to detect the lactol inter-
mediate D. The immediate loss of the water molecule from lactol D
after its evaporation in GC may be the possible reason behind our
failure to detect the lactol D in GCMS. However, to detect the lactol
D, we hypothesized that a coordinating solvent could stop the re-
action in the lactol (D) stage. As a consequence, we conducted the
titled reaction in a coordinating solvent like acetonitrile, which in
turn provided the desired lactol as a mixture of two diastereomers
(D and D’) (Scheme 4). These outcomes eventually reinforced our
proposed reaction pathway.
Fig. 1. NOE response and single-crystal X-ray structure of products.
to render the desired product 2m. ortho-Tolyl cyclopropane car-
baldehyde (1n) containing a single ortho-substituent was also
failed to deliver the expected product 2n. The consequence of these
experiments concludes the fact that the ortho-position of aryl
substituent must be free for a feasible transformation of the sub-
strate into the desired product. To introduce more heteroatom in
the product, the titled reaction was performed with heterocycle-
incorporated cyclopropane carbaldehydes (1o, 1p) like furyl- and
thiophenyl substituted cyclopropane carbaldehyde. Both the
cyclopropane carbaldehydes were effortlessly transformed into
their corresponding product (2o, and 2p).
Based on the previous literature reports and our observation, we
proposed a plausible reaction pathway, as depicted in Scheme 3.
Reaction initiated through activation of cyclopropane carbaldehyde
1 by Brønsted acid to generate an activated intermediate A. After-
wards, the intermediate A committed in a Clock-Wilson rear-
rangement [9] process to render a cyclic enol ether B. Upon
protonation, the enol ether B transformed into an oxocarbenium
ion intermediate C. Next, the oxocarbenium ion intermediate C
engaged in a subsequent hydration process. In this hydration, the
3. Conclusion
In summary, we studied a transformation of cyclopropane car-
baldehydes to oxybis(2-aryltetrahydrofuran) derivatives. The pro-
cess consists of three domino steps, namely Cloke-Wilson
rearrangement, subsequent hydration, and an eventual dimeriza-
tion. Inexpensiveness of the catalyst makes the transformation
economic. Most importantly, all the reactions were carried out in an
open-flask, which revealed the user-friendliness of the process.
Finally, we believe that the future study on this finding will make
water molecule attacks to
a prochiral center, therefore the
approach of water molecule via two alternative faces of prochiral
center leads to giving two diastereomeric lactols D (via pathway m)
Please cite this article as: R. Dey et al., Metal-free domino Cloke-Wilson rearrangement-hydration-dimerization of cyclopropane carbaldehydes:
A facile access to oxybis(2-aryltetrahydrofuran) derivatives, Tetrahedron, https://doi.org/10.1016/j.tet.2020.131080

Table 2
Substrate scopea.
sl. no.
1.
substrate (1)
product (2)
reaction
time (h)
dr
yieldb
47%
(2’:2’’:2’’’)
03
41:45:14
2.c
3.
1.3
05
40:60d
28%
41%
29:51:20
4.
5.
12
15
30:48:22
19:75:06
58%
55%
6.e
7.
8.
9.
48
15
48
48
29:61:10
43%
33:53:14
49%
--
--
--
--
--
10.
11.
48
25
--
37:36:27
45%
Please cite this article as: R. Dey et al., Metal-free domino Cloke-Wilson rearrangement-hydration-dimerization of cyclopropane carbaldehydes:
A facile access to oxybis(2-aryltetrahydrofuran) derivatives, Tetrahedron, https://doi.org/10.1016/j.tet.2020.131080

R. Dey et al. / Tetrahedron xxx (xxxx) xxx
5
this process as economic, eco-friendly and user-friendly pathway to
access various oxybis(2-aryltetrahydrofuran) skeleton.
otherwise specified, all the 1H NMR and 13C NMR spectra were
recorded in CDCl3. Chemical shifts of 1H and 13C NMR spectra are
expressed in parts per million (ppm). All coupling constants are
absolute values and are expressed in Hertz. The description of the
4. Experimental section
signals includes the following:
dd ¼ doublet of doublet, t ¼ triplet, q ¼ quartet, br ¼ broad, and
s
¼
singlet,
d
¼
doublet,
4.1. General information
m ¼ multiplet.
All solvents and reagents were obtained from commercial
sources and were purified following the standard procedure prior
to use. The developed chromatogram was analyzed by UV lamp
(254 nm) or p-anisaldehyde solution. Products were purified by
flash chromatography on silica gel (mesh size 230e400). Unless
4.2. General procedure for preparation of trans-2-
arylcyclopropanecarbaldehydes (1)
trans-2-arylcyclopropanecarbaldehydes were prepared accord-
ing to the literature known procedure as described below
[4a,4b,8e].
1) To a mixture of triethyl phosphonoacetate (1.1 equiv.), DBU
(0.035 equiv.), and finely ground K2CO3 (2 equiv.) was added
ArCHO (1 equiv.) and the resulting mixture was stirred using a
magnetic stirrer for 4 h at room temperature under argon at-
mosphere. Ethyl acetate was added to the crude mixture and the
solid was filtered off. The solid was rinsed with ethyl acetate and
the combined filtrate was concentrated. The resulting oil was
distilled under reduced pressure using a bulb-to-bulb apparatus
(10 mm Hg/240 ꢀC) to give corresponding alkene (yield 84%)
(E:Z ¼ 99:1).
2) A suspension of trimethylsulfoxonium iodide (1.2 equiv.) and
NaH (1.5 equiv.) in anhydrous DMSO (15 mL) was stirred for 1 h.
A DMSO solution (14 mL) of alkene (14 mmol, 1 equiv) was
added at 0 ꢀC. The reaction mixture was stirred at 55 ꢀC for 24 h.
Scheme 3. A plausible mechanism; the origin of the formation of diastereomers.
Fig. 2. Detection of the intermediates by GC-MS.
Scheme 4. Isolation of the lactol intermediate D.
Please cite this article as: R. Dey et al., Metal-free domino Cloke-Wilson rearrangement-hydration-dimerization of cyclopropane carbaldehydes:
A facile access to oxybis(2-aryltetrahydrofuran) derivatives, Tetrahedron, https://doi.org/10.1016/j.tet.2020.131080

6
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Another suspension of trimethylsulfoxonium iodide (0.3 equiv.)
7.25e7.20 (m, 1H), 7.13e7.09 (m, 2H), 2.66e2.60 (m, 1H), 2.21e2.15
(m, 1H), 1.77e1.71 (m, 1H), 1.57e1.51 (m, 1H).
and NaH (0.3 equiv.) in DMSO (10 mL) was added to the reaction
mixture and reaction was stirred at 65 ꢀC for 84 h. The solution
was poured into a brine solution and extracted with ethyl ace-
tate. Combined organic layer was washed with water and dried
over MgSO4, concentrated and purified by silica gel column to
afford corresponding cyclopropane derivative as a white solid
(60e80% yield).
4.2.7. trans-2-(4-Fluorophenyl)cyclopropane-1-carbaldehyde (1g)
1H NMR (400 MHz):
d
9.32 (d, J ¼ 4.5 Hz, 1H), 7.10e7.05 (m, 2H),
6.98 (t, J ¼ 8.7 Hz, 2H), 2.64e2.58 (m, 1H), 2.15e2.09 (m, 1H),
1.74e1.69 (m, 1H), 1.51e1.45 (m, 1H).
3) To a stirred solution of LAH (1.5 equiv.) in 7 mL diethyl ether was
added dropwise a solution of cyclopropane ester (0.90 mmol,
1equiv.) in 3 mL diethyl ether under N2 atmosphere. After
addition was completed the reaction mixture was refluxed for
another 6 h. The reaction mixture was then cooled to rt, and the
excess LAH was destroyed by water. 15 mL of 10% H2SO4 and
8 mL of ether was added and the aqueous layer was extracted
several times with diethyl ether. The combined organic layer
was washed with water and 5% NaHCO3, dried over MgSO4 and
concentrated in a rotary evaporator (90e95% yield). Without
any further purification, the crude material (a colorless oil) was
used for next step.
4.2.8. trans-2-(4-Chlorophenyl)cyclopropane-1-carbaldehyde (1h)
1H NMR (400 MHz):
d
9.33 (d, J ¼ 4.5 Hz, 1H), 7.26 (d, J ¼ 8.7 Hz,
2H), 7.04 (d, J ¼ 8.4 Hz, 2H), 2.63e2.57 (m, 1H), 2.17e2.11 (m, 1H),
1.76e1.70 (m, 1H), 1.52e1.46 (m, 1H).
4.2.9. trans- 2-(3-Bromophenyl)cyclopropane-1-carbaldehyde (1i)
1H NMR (400 MHz):
1H), 7.27e7.24 (m, 1H), 7.16 (t, J ¼ 7.9 Hz, 1H), 7.05 (d, J ¼ 7.7 Hz, 1H),
2.62e2.56 (m, 1H), 2.21e2.15 (m, 1H), 1.76e1.71 (m, 1H), 1.52e1.48
(m, 1H).
d
9.36 (d, J ¼ 4.2 Hz, 1H), 7.36 (d, J ¼ 7.9 Hz,
4.2.10. trans- 2-(3-Methoxyphenyl)cyclopropane-1-carbaldehyde
4)To a solution of cyclopropane alcohol (6.8 mmol, 1 equiv.) in
dry DCM (14 mL), PCC (2 equiv.) was added in a portion-wise
manner through a solid addition tube under N2 atmosphere.
After 3 h reaction mixture was filtered through a small plug of
celite and concentrated in vacuo. The crude mixture was puri-
fied by silica gel column chromatography using ethyl acetate in
hexane as an eluent. Starting from aryl aldehyde the 2-
arylcyclopropanecarbaldehydes was obtained in 40e50% over-
all yield.
(1j)
1H NMR (400 MHz):
d
9.32 (d, J ¼ 4.5 Hz, 1H), 7.21 (t, J ¼ 7.9 Hz,
1H), 6.79e6.64 (m, 3H), 3.79 (s, 3H), 2.64e2.57 (m, 1H), 2.21e2.14
(m, 1H), 1.75e1.69 (m, 1H), 1.55e1.50 (m, 1H).
4.2.11. trans- 2-(Naphthalen-2-yl)cyclopropane-1-carbaldehyde
(1k)
1H NMR (400 MHz):
d
9.38 (d, J ¼ 4.5 Hz, 1H), 7.83e7.76 (m, 3H),
7.59 (s, 1H), 7.51e7.42 (m, 2H), 7.21 (dd, J ¼ 8.4, 1.8 Hz, 1H),
2.83e2.77 (m, 1H), 2.31e2.25 (m, 1H), 1.84e1.78 (m, 1H), 1.69e1.62
(m, 1H).
4.2.1. trans-2-(4-Methoxyphenyl)cyclopropane-1-carbaldehyde
(1a)
4.2.12. trans- 2-(Naphthalen-1-yl)cyclopropane-1-carbaldehyde
1H NMR (400 MHz):
d
9.30 (d, J ¼ 4.9 Hz, 1H), 7.05 (d, J ¼ 8.7 Hz,
(1l)
1H NMR (400 MHz):
d
9.54 (d, J ¼ 8.6 Hz, 1H), 8.14 (d, J ¼ 8.6 Hz,
2H), 6.83 (d, J ¼ 8.7 Hz, 2H), 3.79 (s, 3H) 2.63e2.56 (m, 1H),
2.13e2.06 (m, 1H), 1.73e1.67 (m, 1H), 1.51e1.45 (m, 1H).
1H), 7.88 (d, J ¼ 7.1 Hz, 1H), 7.79 (d, J ¼ 8.6 Hz, 1H), 7.60e7.50 (m,
2H), 7.41 (t, J ¼ 7.1 Hz, 1H), 7.29 (t, J ¼ 7.1 Hz, 1H), 2.22e2.16 (m, 1H),
1.88e1.82 (m, 1H), 1.72e1.67 (m, 2H).
4.2.2. trans-2-(Benzo[d][1,3]dioxol-5-yl)cyclopropanecarbaldehyde
(1b)
1H NMR (400 MHz):
d
9.30 (d, J ¼ 4.59 Hz, 1H), 6.73 (d,
4.2.13. trans- 2-Mesitylcyclopropane-1-carbaldehyde (1m)
1H NMR (400 MHz):
d
9.28 (d, J ¼ 5.4 Hz, 1H), 6.85 (s, 2H),
J ¼ 7.78 Hz, 1H), 6.62 (d, J ¼ 8.09 Hz, 1H), 6.57 (d, J ¼ 1.84 Hz, 1H),
5.93 (s, 2H), 2.60e2.55 (m, 1H), 2.12e2.04 (m, 1H), 1.71e1.66 (m,
1H), 1.49e1.43 (m, 1H).
2.45e2.39 (m, 1H), 2.33 (s, 6H), 2.25 (s, 3H), 1.98e1.91 (m, 1H),
1.82e1.76 (m, 1H), 1.40e1.34 (m, 1H).
4.2.3. trans-2-(4-(Benzyloxy)phenyl)cyclopropane-1-carbaldehyde
4.2.14. trans- 2-(o-Tolyl)cyclopropane-1-carbaldehyde (1n)
1H NMR (400 MHz):
d
9.37 (d, J ¼ 4.6 Hz, 1H), 7.19e7.12 (s, 3H),
(1c)
1H NMR (400 MHz):
d
9.30 (d, J ¼ 4.5 Hz, 1H), 7.44e7.31 (m, 5H),
7.04e7.00 (m, 1H), 2.66e2.60 (m, 1H), 2.36 (s, 3H), 2.07e2.01 (m,
1H), 1.74e1.69 (m, 1H), 1.59e1.53 (m, 1H).
7.04 (d, J ¼ 8.5 Hz, 2H), 6.90 (d, J ¼ 8.6 Hz, 2H), 5.04 (s, 2H),
2.62e2.55 (m, 1H), 2.13e2.06 (m, 1H), 1.72e1.67 (m, 1H), 1.51e1.45
(m, 1H).
4.2.15. trans-2-(Furan-2-yl)cyclopropanecarbaldehyde (1o)
1H NMR (400 MHz):
6.30e6.28 (m, 1H), 6.10 (d, J ¼ 3.3 Hz, 1H), 2.65e2.59 (m, 1H),
2.32e2.26 (m, 1H), 1.69e1.64 (m, 1H), 1.62e1.56 (m, 1H).
d
9.36 (d, J ¼ 4.3 Hz, 1H), 7.27e7.25 (m, 1H),
4.2.4. trans-2-(p-Tolyl)cyclopropane-1-carbaldehyde (1d)
1H NMR (400 MHz):
d
9.30 (d, J ¼ 4.5 Hz, 1H), 7.11 (d, J ¼ 8.0 Hz,
2H), 7.01 (d, J ¼ 8.2 Hz, 2H), 2.63e257 (m, 1H), 2.32 (s, 3H),
2.16e2.10 (m, 1H), 1.74e1.68 (m, 1H), 1.54e1.48 (m, 1H).
4.2.16. trans-2-(Thiophen-2-yl)cyclopropane-1-carbaldehyde (1p)
1H NMR (400 MHz):
0.9 Hz, 1H), 6.92 (dd, J ¼ 5.0, 3.6 Hz, 1H), 6.85 (d, J ¼ 3.6 Hz, 1H),
2.85e2.79 (m, 1H), 2.26e2.17 (m, 1H), 1.79e1.74 (m, 1H), 1.56e1.50
(m, 1H).
d
9.38 (d, J ¼ 4.1 Hz, 1H), 7.13 (dd, J ¼ 5.0,
4.2.5. trans-2-(4-Isopropylphenyl)cyclopropane-1-carbaldehyde
(1e)
1H NMR (400 MHz):
d
9.31 (d, J ¼ 4.5 Hz, 1H), 7.17 (d. J ¼ 8.2 Hz,
2H), 7.06 (d, J ¼ 8.2 Hz, 2H), 2.95e2.84 (m, 1H), 2.65e2.58 (m, 1H),
2.19e2.13 (m, 1H), 1.75e1.69 (m, 1H), 1.56e1.49 (m, 1H), 1.24 (d,
J ¼ 6.8 Hz, 6H).
4.3. Representative procedure for rearrangement-dimerization
reaction of 2-arylcyclopropanecarbaldehydes
4.2.6. trans- 2-phenylcyclopropane-1-carbaldehyde (1f)
To a round-bottom flask equipped with a magnetic stir bar was
charged with PTSA (0.028 mmol, 0.1 equiv). A DCM (2.8 mL)
1H NMR (400 MHz):
d
9.32 (d, J ¼ 4.5 Hz, 1H), 7.33e7.27 (m, 2H),
Please cite this article as: R. Dey et al., Metal-free domino Cloke-Wilson rearrangement-hydration-dimerization of cyclopropane carbaldehydes:
A facile access to oxybis(2-aryltetrahydrofuran) derivatives, Tetrahedron, https://doi.org/10.1016/j.tet.2020.131080

R. Dey et al. / Tetrahedron xxx (xxxx) xxx
7
solution of cyclopropane carbaldehyde 1 (0.284 mmol, 1 equiv) was
added and stirred at room temperature until completion of the
reaction (as monitored by TLC). The solvent was evaporated on a
rotary evaporator. The crude mixture was further purified by col-
umn chromatography on silica gel with ethyl acetate/hexane as
eluent.
This reaction produced the product 2 as a mixture of three di-
astereomers. These diastereomers are respectively 2′, 2’’ and 2000.
For characterization and conformational analysis, the spectroscopic
data for three individual diastereomer has been given for only one
product (2a) and for other products the spectroscopic data of only
one diastereomer (2’) has been given.
4.3.5. 5,50-Oxybis(2-(4-isopropylphenyl)tetrahydrofuran) (2e)
Reaction time: 15 h, 1e (0.050 g, 0.265 mmol), 2e (0.057 g,
0.145 mmol), yield: 55%, nature: pale yellow sticky compound, Rf-
value: 0.68 (ethyl acetate: hexane) ¼ 1:9, (v/v), 1H-NMR (400 MHz):
d
7.26 (d, J ¼ 8.25 Hz, 2H), 7.20 (d, J ¼ 8.14 Hz, 2H), 5.75 (dd, J ¼ 5.45,
1.78 Hz, 1H), 5.08 (t, J ¼ 7.04 Hz, 1H), 2.95e2.84 (m, 1H), 2.45e2.36
(m, 1H), 2.26e2.17 (m, 1H), 2.01e1.93 (m, 1H), 1.83e1.74 (m, 1H),
1.24 (d, J ¼ 6.89 Hz, 6H), 13C-NMR (100 MHz):
d 148.2, 139.8, 126.5,
126.0, 100.8, 79.5, 33.9, 32.8, 32.6, 24.2, 24.1, IR (neat): 2956, 2916,
2848, 1358, 2335, 1724, 1701, 1512, 1458, 1361, 1334, 1240, 1180,
1087, 1053, 1022, 979, 827, 736, 563 cmꢁ1, HRMS (ESI, Q-TOF) m/z:
[M þ Na]þ Calculated for C26H34O3Na 417.2406 found 417.2403.
4.3.1. 5,50-Oxybis(2-(4-methoxyphenyl)tetrahydrofuran) (2a)
Reaction time: 03 h, 1a (0.050 g, 0.284 mmol), 2a (0.049 g,
0.133 mmol), yield: 47%, nature: pale yellow paste, Rf-value: 0.6
4.3.6. 5,50-Oxybis(2-phenyltetrahydrofuran) (2f)
Reaction time: 48 h, 1f (0.050 g, 0.344 mmol), 2f (0.046 g,
0.147 mmol), yield: 43%, nature: pale yellow cream like compound,
Rf-value: 0.72 (ethyl acetate: hexane) ¼ 1:9, (v/v), 1H-NMR
(ethyl acetate: hexane) ¼ 2:8, (v/v), 1H-NMR (400 MHz):
d 7.26 (d,
J ¼ 8.61 Hz, 2H), 6.87 (d, J ¼ 8.72 Hz, 2H), 5.74 (dd, J ¼ 5.54, 2.07 Hz,
1H), 5.06 (t, J ¼ 7.15 Hz, 1H), 3.79 (s, 3H), 2.43e2.34 (m, 1H),
2.27e2.17 (m, 1H), 2.01e1.93 (m, 1H), 1.79e1.69 (m, 1H), 13C-NMR
(400 MHz):
d
7.34 (d, J ¼ 4.33 Hz, 4H), 7.28e7.24 (m, 1H), 5.78 (dd,
J ¼ 5.50, 1.98 Hz, 1H), 5.12 (t, J ¼ 7.21 Hz, 1H), 2.49e2.39 (m, 1H),
2.26e2.17 (m, 1H), 2.01e1.94 (m, 1H), 1.82e1.72 (m, 1H), 13C-NMR
(100 MHz):
d 142.6, 128.4, 127.4, 125.9, 100.9, 79.6, 32.9, 32.4, IR
(100 MHz):
d 159.0, 134.6, 127.2, 113.8, 100.8, 79.3, 55.4, 32.9, 32.6,
IR (neat): 2951, 2853, 1720, 1689, 1610, 1585, 1512, 1460, 1440, 1334,
1292, 1242, 1170, 1109, 1029, 974, 827, 761, 540 cmꢁ1, HRMS (ESI, Q-
TOF) m/z: [M þ Na]þ Calculated for C22H26O5Na 393.1678 found
393.1676.
(neat): 2918, 2848, 1726, 1490, 1454, 1240,1180, 1022, 981, 943, 906,
846, 800, 754, 698 cmꢁ1, HRMS (ESI, Q-TOF) m/z: [M þ Na]þ
Calculated for C20H22O3Na 333.1467 found 333.1465.
4.3.7. 5,50-Oxybis(2-(4-fluorophenyl)tetrahydrofuran) (2g)
Reaction time: 15 h, 1g (0.050 g, 0.304 mmol), 2g (0.051 g,
0.148 mmol), yield: 49%, nature: light grey sticky compound, Rf-
4.3.2. 4-(5-((5-(Benzo[d][1,3]dioxol-5-yl)tetrahydrofuran-2 yl)oxy)
tetrahydrofuran-2-yl)benzo[d][1,3]dioxole (2b)
Reaction time: 1.3 h, 1b (0.050 g, 0.263 mmol), 2b (0.029 g,
0.073 mmol), yield: 28%, nature: colourless oil, Rf-value: 0.36 (ethyl
value: 0.5 (ethyl acetate: hexane)
(400 MHz):
¼
0.5:9.5, (v/v), 1H-NMR
d
7.30 (dd, J ¼ 8.77, 5.53 Hz, 2H), 7.02 (t, J ¼ 8.77 Hz, 2H),
acetate: hexane) ¼ 1:9, (v/v), 1H-NMR (400 MHz):
d
6.84e6.75 (m,
5.75 (dd, J ¼ 5.54, 2.10 Hz, 1H), 5.09 (t, J ¼ 7.30 Hz, 1H), 2.47e2.37
(m, 1H), 2.26e2.16 (m, 2H), 2.01e1.93 (m, 4H), 1.77e1.62 (m, 1H),
3H), 5.93 (s, 2H), 5.72 (dd, J ¼ 5.51, 2.32 Hz, 1H), 5.02 (t, J ¼ 7.26 Hz,
1H), 2.42e2.33 (m, 1H), 2.25e2.16 (m, 1H), 1.99e1.91 (m, 1H),
13C-NMR (100 MHz):
d 163.4, 161.0, 138.2, 127.6, 127.5, 115.4, 115.2,
1.77e1.67 (m, 1H), 13C-NMR (100 MHz):
d
147.8, 146.9, 136.5, 119.3,
100.7, 79.0, 33.0, 32.4, IR (neat): 2922, 2850, 1732, 1604, 1508, 1460,
1294, 1224, 1184, 1155, 1080, 1024, 981, 945, 831, 534 cmꢁ1, HRMS
(ESI, Q-TOF) m/z: [M þ Na]þ Calculated for C20H20O3F2Na 369.1278
found 369.1276.
108.1,106.5,101.0, 100.8, 79.5, 33.0, 32.4, IR (neat): 2920,1502,1487,
1442, 1334, 1244, 1184, 1097, 1037, 981, 935, 873, 810, 732, 702,
540 cmꢁ1, HRMS (ESI, Q-TOF) m/z: [M þ Na]þ Calculated for
C
22H22O7Na 421.1263 found 421.1289.
4.3.8. 5,50-Oxybis(2-(naphthalen-2-yl)tetrahydrofuran) (2k)
Reaction time: 25 h, 1k (0.050 g, 0.255 mmol), 2k (0.047 g,
0.115 mmol), yield: 45%, nature: off white semi solid, Rf-value: 0.56
4.3.3. 5,50-Oxybis(2-(4-(benzyloxy)phenyl)tetrahydrofuran) (2c)
Reaction time: 5 h, 1c (0.050 g, 0.198 mmol), 2c (0.042 g,
0.081 mmol), yield: 41%, nature: off white sticky compound, Rf-
value: 0.58 (ethyl acetate: hexane) ¼ 2:8, (v/v), 1H-NMR (400 MHz):
(ethyl acetate: hexane)
7.85e7.80 (m, 4H), 7.50e7.42 (m, 3H), 5.89 (dd, J ¼ 5.40, 1.83 Hz,
1H), 5.32 (t, J ¼ 7.19 Hz, 1H), 2.58e2.49 (m, 1H), 2.33e2.23 (m, 1H),
2.10e2.01 (m, 1H), 1.92e1.83 (m, 1H), 13C-NMR (100 MHz):
140.1,
¼
1:9, (v/v), 1H-NMR (400 MHz):
d
d
7.45e7.36 (m, 4H), 7.34e7.33 (m,1H), 7.26 (d, J ¼ 8.53 Hz, 2H), 6.95
(d, J ¼ 8.67 Hz, 2H), 5.73 (dd, J ¼ 5.37, 2.03 Hz, 1H), 5.05 (t,
d
J ¼ 7.22 Hz, 3H), 2.43e2.34 (m, 1H), 2.27e2.17 (m, 1H), 2.01e1.92
133.3, 132.9, 128.3, 128.0, 127.8, 126.2, 125.8, 124.4,124.1, 101.0, 79.8,
32.9, 32.4, IR (neat): 2920, 2848, 2357, 1716, 1600, 1508, 1458, 1263,
983, 937, 893, 856, 817, 732, 702, 476 cmꢁ1, HRMS (ESI, Q-TOF) m/z:
[MþNa]þ Calculated for C28H26O3Na 433.1780 found 433.1779.
(m, 1H), 1.80e1.69 (m, 1H), 13C-NMR (100 MHz):
d 158.2, 137.1,
134.8, 128.7, 128.0, 127.5, 127.2, 114.8, 100.8, 79.3, 70.1, 32.9, 32.6, IR
(neat): 2920, 2852, 1732, 1678, 1600, 1510, 1454, 1240, 1172, 1124,
1018, 981, 960, 827, 732, 696, 542 cmꢁ1, HRMS (ESI, Q-TOF) m/z:
[M þ Na]þ Calculated for C34H34O5Na 545.2304 found 545.2309.
4.3.9. 5,50-Oxybis(2-(naphthalen-1-yl)tetrahydrofuran) (2l)
Reaction time: 48 h, 1l (0.050 g, 0.255 mmol), 2l (0.040 g,
0.096 mmol), yield: 38%, nature: off white sticky compound, Rf-
value: 0.55 (ethyl acetate: hexane) ¼ 1:9, (v/v), 1H-NMR (400 MHz):
4.3.4. 5,50-Oxybis(2-(p-tolyl)tetrahydrofuran) (2d)
Reaction time: 12 h, 1d (0.050 g, 0.312 mmol), 2d (0.061 g,
0.180 mmol) yield: 58%, nature: colourless semisolid, Rf-value: 0.70
d
8.00 (d, J ¼ 8.16 Hz, 1H), 7.89 (d, J ¼ 8.46 Hz, 1H), 7.78 (d,
(ethyl acetate: hexane) ¼ 1:9, (v/v), 1H-NMR (400 MHz):
d
7.23 (d,
J ¼ 8.26 Hz, 1H), 7.67 (d, J ¼ 6.91 Hz, 1H), 7.55e7.45 (m, 3H), 5.98
(dd, J ¼ 5.07, 1.29 Hz, 1H), 5.92 (t, J ¼ 6.71 Hz, 1H), 2.80e2.70 (m,
1H), 2.25e2.16 (m, 1H), 2.15e2.06 (m, 1H), 1.95e1.87 (m, 1H), 13C-
J ¼ 8.02 Hz, 2H), 7.15 (d, J ¼ 8.01 Hz, 2H), 5.75 (dd, J ¼ 5.54, 1.87 Hz,
1H), 5.09 (t, J ¼ 7.24 Hz, 1H), 2.45e2.36 (m, 1H), 2.33 (s, 3H),
2.25e2.16 (m, 1H), 2.01e1.93 (m, 1H), 1.80e1.70 (m, 1H), 13C-NMR
NMR (100 MHz):
d 138.5, 133.8, 130.3, 128.9, 127.7, 126.0, 125.6,
(100 MHz):
d
139.6, 137.1, 129.1, 125.8, 100.8, 79.5, 33.0, 32.5, 21.2, IR
125.5, 123.4, 122.1, 100.6, 32.1, 31.8, IR (neat): 3049, 2922, 2852,
1720, 1597, 1508, 1485, 1386, 1323, 1261, 1170, 1089, 1051, 1026, 960,
931, 912, 852, 798, 773, 736, 572, 555, 497 cmꢁ1, HRMS (ESI, Q-TOF)
m/z: [MþNa]þ Calculated for C28H26O3Na 433.1780 found 433.1786.
(neat): 2949, 2920, 2852, 1516, 1458, 1330, 1170, 1085, 1020, 979,
958, 844, 810, 526 cmꢁ1, HRMS (ESI, Q-TOF) m/z: [M þ Na]þ
Calculated for C22H26O3Na 361.1780 found 361.1790.
Please cite this article as: R. Dey et al., Metal-free domino Cloke-Wilson rearrangement-hydration-dimerization of cyclopropane carbaldehydes:
A facile access to oxybis(2-aryltetrahydrofuran) derivatives, Tetrahedron, https://doi.org/10.1016/j.tet.2020.131080

8
R. Dey et al. / Tetrahedron xxx (xxxx) xxx
(c) L.F. Tietze, Chem. Rev. 96 (1996) 115e136.
[2] (For reviews on donor-acceptor cyclopropane see;
R. Zimmer, Chem. Rev. 103 (2003) 1151e1196;
4.3.10. 2,2’-(Oxybis(tetrahydrofuran-5,2-diyl))difuran (2o)
Reaction time: 1.6 h, 1o (0.050 g, 0.367 mmol), 2o (0.045 g,
0.154 mmol), yield: 42%, nature: light black oil, Rf-value: 0.55 (ethyl
)
(a) H.-U. Reissig,
(b) T.F. Schneider, J. Kaschel, D.B. Werz, Angew. Chem. Int. Ed. 53 (2014)
5504e5523;
(c) A.K. Pandey, A. Ghosh, P. Banerjee, Isr. J. Chem. 56 (2016) 512e521;
(d) E.M. Budynina, K.L. Ivanov, I.D. Sorokin, M.Y. Melnikov, Synthesis 49
(2017) 3035e3068;
(e) D. B. Werz, A. T. Biju, Angew. Chem. Int. Ed. 10.1002/anie.201909213: (For
recent reports see); (f) A.U. Augustin, P.G. Jones, D.B. Werz, Chem. Eur J. 25
(2019) 11620e11624;
(g) L.K.B. Garve, P.G. Jones, D.B. Werz, Angew. Chem. Int. Ed. 56 (2017)
9226e9230;
acetate: hexane) ¼ 1:9, (v/v), 1H-NMR (400 MHz):
d 7.38 (d,
J ¼ 1.55 Hz, 1H), 6.33e6.31 (m, 1H), 6.27 (d, J ¼ 3.09 Hz, 1H), 5.63
(dd, J ¼ 5.12, 1.48 Hz, 1H), 5.10 (t, J ¼ 6.54 Hz, 1H), 2.36e2.20 (m,
2H), 2.12e2.02 (m, 1H), 2.01e1.94 (m, 1H), 13C-NMR (100 MHz):
d
154.3, 142.5, 110.2, 107.1, 100.9, 73.1, 32.4, 28.6, IR (neat): 2922,
2852, 1720, 1458, 1340, 1236, 1149, 1074, 975, 931, 881, 848, 804,
736, 599 cmꢁ1, HRMS (ESI, Q-TOF) m/z: [M þ Na]þ Calculated for
(h) S. Das, C.G. Daniliuc, A. Studer, Angew. Chem. Int. Ed. 57 (2018)
4053e4057;
C
16H18O5Na 313.1052 found 313.1057.
(i) W. Luo, Z. Sun, E.H.N. Fernando, V.N. Nesterov, T.R. Cundari, H. Wang, ACS
Catal. 9 (2019) 8285e8293;
4.3.11. 5,50-Oxybis(2-(thiophen-2-yl)tetrahydrofuran) (2p)
(j) L. C. Irwin, M. A. Allen, M. R. Vriesen, M. A. Kerr, Chem. Eur J. 10.1002/
chem.201904521; (k) A.O. Chagarovskiy, V.S. Vasin, V.V. Kuznetsov,
O.A. Ivanova, V.B. Rybakov, A.N. Shumsky, N.N. Makhova, I.V. Trushkov,
Angew. Chem. Int. Ed. 57 (2018) 10338e10342;
(l) A.U. Augustin, M. Busse, P.G. Jones, D.B. Werz, Org. Lett. 20 (2018)
820e823;
Reaction time: 2.5 h, 1p (0.050 g, 0.328 mmol), 2p (0.045 g,
0.141 mmol), yield: 43%, nature: light yellow viscous liquid, Rf-
value: 0.53 (ethyl acetate: hexane) ¼ 1:9, (v/v), 1H-NMR (400 MHz):
d
7.23 (dd, J ¼ 4.60, 1.36 Hz, 1H), 6.98e6.94 (m, 2H), 5.69 (dd,
J ¼ 5.45, 1.82 Hz, 1H), 5.35 (t, J ¼ 6.82 Hz, 1H), 2.48e2.40 (m, 1H),
(m) Y. Matsumoto, D. Nakatake, R. Yazaki, T. Ohshima, Chem. Eur J. 24 (2018)
6062e6066;
2.30e2.22 (m, 1H), 2.02e1.88 (m, 2H), 13C-NMR (100 MHz):
d
126.7,
(n) Z.-H. Wang, H.-H. Zhang, P.-F. Xu, Y.-C. Luo, Chem. Commun. 54 (2018)
10128e10131.
124.7, 124.1, 100.7, 75.9, 33.1, 32.4, IR (neat): 2924, 2850, 1458, 1438,
1263, 1091, 1016, 977, 935, 893, 850, 829, 732, 698 cmꢁ1, HRMS (ESI,
Q-TOF) m/z: [M þ Na]þ Calculated for C16H18O3Na 345.0595 found
345.0605.
[3] (Natural product synthesis from donor-acceptor cyclopropane; For reviews
see ) (a) S.J. Gharpure, L.N. Nanda, Tetrahedron Lett. 58 (2017) 711e720;
(b) P. Tang, Y. Qin, Synthesis 44 (2012) 2969e2984;
(c) S.E. Reisman, R.R. Nani, S. Levin, Synlett 17 (2011) 2437e2442;
(d) C.A. Carson, M.A. Kerr, Chem. Soc. Rev. vol. 38 (2009) 3051e3060 (For
recent reports see);
4.4. Representative procedure for preparation of 5-(4-
methoxyphenyl)tetrahydrofuran-2-ol (D þ D’)
(e) P. Liu, Y. Cui, K. Chen, X. Zhou, W. Pan, J. Ren, Z. Wang, Org. Lett. 20 (2018)
2517e2521;
(f) S.J. Gharpure, L.N. Nanda, Asian J. Org. Chem. 6 (2017) 977e980;
(g) J.-A. Xiao, P.-J. Xia, X.-Y. Zhang, X.-Q. Chen, G.-C. Oub, H. Yang, Chem.
Commun. 52 (2016) 2177e2180;
To a round-bottom flask equipped with a magnetic stir bar was
charged with PTSA (0.056 mmol, 0.2 equiv). An acetonitrile (2.8 mL)
solution of cyclopropane carbaldehyde 1a (0.284 mmol, 1 equiv)
was added and stirred at room temperature until completion of the
reaction (as monitored by TLC). The solvent was evaporated on a
rotary evaporator. The crude mixture was further purified by col-
umn chromatography on silica gel with ethyl acetate/hexane as
eluent. The physical characteristic data and the spectroscopic data
of the isolated compound was matched with the previously re-
ported literature data [11a,11b].
(h) S.J. Gharpure, L.N. Nanda, M.K. Shukla, Org. Lett. 16 (2014) 6424e6642;
(i) A.B. Leduc, M.A. Kerr, Angew. Chem. Int. Ed. 47 (2008) 7945e7948.
[4] (a) P. Kumar, R. Dey, P. Banerjee, Org. Lett. 20 (2018) 5163e5166;
(b) R. Dey, P. Kumar, P. Banerjee, J. Org. Chem. 83 (2018) 5438e5449;
(c) K. Verma, P. Banerjee, Adv. Synth. Catal. 360 (2018) 3687e3692;
(d) R. Dey, P. Banerjee, Org. Lett. 19 (2017) 304e307;
(e) K. Verma, P. Banerjee, Adv. Synth. Catal. 359 (2017) 3848e3854;
(f) A. Ghosh, S. Mandal, P.K. Chattaraj, P. Banerjee, Org. Lett. 18 (2016)
4940e4943;
(g) A. Ghosh, A.K. Pandey, P. Banerjee, J. Org. Chem. 80 (2015) 7235e7242.
[5] Dimerization of donor-acceptor cyclopropane; see the review R.A. Novikov,
Y.V. Tomilov, Mendeleev Commun. 25 (2015) 1e10. and see the reference
therein).
[6] (a) C.-L. Sun, Z.-J. Shi, Chem. Rev. 114 (2014) 9219e9280;
(b) H. Miyamoto, C. Sakumoto, E. Takekoshi, Y. Maeda, N. Hiramoto, T. Itoh,
Y. Kato, Org. Process Res. Dev. 19 (2015) 1054e1061;
(c) C.E. Garrett, K. Prasad, Adv. Synth. Catal. 346 (2004) 889e900.
[7] (a) J. Wallbaum, L.K.B. Garve, P.G. Jones, D.B. Werz, Chem. Eur J. 22 (2016)
18756e18759;
(b) C. Sparr, R. Gilmour, Angew. Chem. Int. Ed. 50 (2011) 8391e8395.
[8] (a) E. Richmond, V.D. Vukovic, J. Moran, Org. Lett. 20 (2018) 574e577;
(b) E. Richmond, J. Yi, V.D. Vukovic, F. Sajadi, C.N. Rowley, J. Moran, Chem. Sci.
9 (2018) 6411e6416;
1a (0.050 g, 0.284 mmol), D þ D’ (0.028 g, 0.144 mmol), yield:
51%, nature: colourless syrup, Rf-value: 0.4 (ethyl acetate:
hexane) ¼ 3:7, (v/v), 1H-NMR (400 MHz):
7.36 (d, J ¼ 8.70 Hz, 2H),
d
7.24 (d, J ¼ 8.70 Hz, 2H), 6.89 (d, J ¼ 3.20 Hz, 2H), 6.87 (d, J ¼ 3.17 Hz,
2H), 5.75 (dd, J ¼ 4.98, 1.87 Hz, 1H), 5.60 (d, J ¼ 3.18 Hz, 1H), 5.19 (t,
J ¼ 8.07 Hz, 1H), 4.99e4.93 (m, 1H), 3.80 (s, 3H), 3.80 (s, 3H), 2.99 (s,
3H), 2.89 (s, 3H), 2.47e2.38 (m, 1H), 2.26e2.16 (m, 2H), 2.12e2.03
(m, 3H), 1.99e1.91 (m, 1H), 1.83e1.74 (m, 1H), 13C-NMR (100 MHz):
d
159.2, 159.1, 134.8, 134.3, 127.9, 127.1, 113.9, 98.9, 98.6, 82.8, 79.5,
55.4, 34.7, 33.4, 32.8, 32.6.
(c) L.C. Irwin, C.R. Renwick, M.A. Kerr, J. Org. Chem. 83 (2018) 6235e6242;
ꢀ
ꢀ
(d) S. Gonzalez-Pelayo, L.A. Lopez, ChemPlusChem 83 (2018) 1008e1012;
(e) R. Dey, P. Banerjee, Adv. Synth. Catal. 361 (2019) 2849e2854.
[9] (a) J.B. Cloke, J. Am. Chem. Soc. 51 (1929) 1174;
(b) C.L. Wilson, J. Am. Chem. Soc. 69 (1947) 3002;
Acknowledgments
The authors gratefully acknowledge financial assistance from
the Department of Science and Technology, New Delhi, India, and
the Council of Scientific and Industrial Research (CSIR-India). R.D.
thanks IIT Ropar for his doctoral fellowship.
(c) T.F. Schneider, J. Kaschel, B. Dittrich, D.B. Werz, Org. Lett. 11 (2009)
2317e2320;
(d) T.F. Schneider, J. Kaschel, S.I. Awan, B. Dittrich, D.B. Werz, Chem. Eur J. 16
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(e) E. Gopi, I.N.N. Namboothiri, J. Org. Chem. 78 (2013) 910e919;
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Appendix A. Supplementary data
Supplementary data to this article can be found online at
https://doi.org/10.1016/j.tet.2020.131080.
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[10] CCDC 1966104 contains supplementary crystallographic data for the com-
pound 2a’’
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Please cite this article as: R. Dey et al., Metal-free domino Cloke-Wilson rearrangement-hydration-dimerization of cyclopropane carbaldehydes:
A facile access to oxybis(2-aryltetrahydrofuran) derivatives, Tetrahedron, https://doi.org/10.1016/j.tet.2020.131080