Cascade dimerization of 2-styryl-1,1-cyclopropanedicarboxylate upon treatment with gallium trichloride

Article abstract of DOI:10.1007/s11172-016-1628-0

2-Styrylcyclopropane-1,1-dicarboxylate treated with anhydrous gallium trichloride undergoes dimerization with the cyclopropane ring opening and the styryl substituent double bond involvement, leading to the formation of polysubstituted cyclic and bicyclic structures with the predominance of the former or the latter depending on the reaction conditions. Most compounds are formed with very high diastereoselectivity. Thirteen major and minor dimeric structures were isolated and reliably characterized, two of which were found to additionally include a chlorine atom. A rare for the reactions of donor-acceptor cyclopropanes example of the formation of a product with the fused cyclobutane ring was effected at–80 °C. Plausible mechanisms of observed processes were discussed.

Full text of DOI:10.1007/s11172-016-1628-0

2628
Russian Chemical Bulletin, International Edition, Vol. 65, No. 11, pp. 2628—2638, November, 2016
Cascade dimerization of 2ꢀstyrylꢀ1,1ꢀcyclopropanedicarboxylate
upon treatment with gallium trichloride*
R. A. Novikov, A. V. Tarasova, D. A. Denisov, V. A. Korolev, and Yu. V. Tomilov
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences,
4
7 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 6390. Eꢀmail: tom@ioc.ac.ru
2
ꢀStyrylcyclopropaneꢀ1,1ꢀdicarboxylate treated with anhydrous gallium trichloride underꢀ
goes dimerization with the cyclopropane ring opening and the styryl substituent double bond
involvement, leading to the formation of polysubstituted cyclic and bicyclic structures with the
predominance of the former or the latter depending on the reaction conditions. Most comꢀ
pounds are formed with very high diastereoselectivity. Thirteen major and minor dimeric
structures were isolated and reliably characterized, two of which were found to additionally
include a chlorine atom. A rare for the reactions of donorꢀacceptor cyclopropanes example of
the formation of a product with the fused cyclobutane ring was effected at –80 °C. Plausible
mechanisms of observed processes were discussed.
Key words: 2ꢀstyrylꢀ1,1ꢀcyclopropanedicarboxylate, gallium trichloride, cascade dimerizaꢀ
tion, diastereoselectivity.
Cyclopropanes with the vicinal donor and acceptor
used as the sources of 1,3ꢀzwitterions1—9 involving in the
reactions with a wide scope of substrates.
substituents (donorꢀacceptor cyclopropanes, DAC) are reꢀ
garded as building blocks and are widely used in modern
organic synthesis for construction of various carboꢀ and
heterocyclic systems.1 The most frequently DAC are
In the absence of substrates, DAC can undergo isoꢀ
merization or be involved in the dimerization reactions
—9
9—17
(Scheme 1).
These reactions are interesting from the
Scheme 1
*
Dedicated to Academician of the Russian Academy of Sciences O. M. Nefedov on the occasion of his 85th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2628—2638, November, 2016.
066ꢀ5285/16/6511ꢀ2628 © 2016 Springer Science+Business Media, Inc.
1

GaCl ꢀMediated cascade dimerization
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016 2629
3
point of view that allows one to assemble quite complex
carboꢀ and heterocyclic skeletons, including polyannulated,
in one step from one simple substrate. In most cases, these
reactions proceed with high regioꢀ and diastereoselectivity,
and the formed compounds can be used as synthons in
subsequent chemical transformations and for the synthesis
of analogs of biologically active and natural compounds.
Apart from that, mechanistic aspects of the observed transꢀ
formations are very interesting. At the present time, it is
known that dimerization of DAC can follow a large variety
of directions, and the studies of these transformation conꢀ
ZnCl , InCl , TMSOTf, Sn(OTf) , Cu(OTf) , Sc(OTf) ,
2
3
2
2
3
Yb(OTf) , In(OTf) , Ni(ClO ) , MgI . The introduction
3
3
4 2
2
into the reaction of different additional substrates did not
change much, and the reactions followed the usual for
DAC pathways without involvement of the styryl substituꢀ
1
—9,18—21
ent.
The situation was changed when a specific Lewis acid,
anhydrous gallium trichloride, was used, the application
of which in the reactions of DAC have been intensively
studied by our research group. In fact, GaCl under cerꢀ
3
tain conditions turned out to be the only Lewis acid capaꢀ
ble of involving into the chemical transformations of both
the cyclopropane ring and the double bond in DAC 2 with
the formation of identifiable compounds.
The processes in these transformations can be separatꢀ
ed in two types, namely, proceeding at reduced and eleꢀ
vated temperatures. Thus, the processes of isomerization
of cyclopropane 2 predominantly take place at the temꢀ
peratures above 20 °C (Scheme 2), which mainly give the
product of vinylcyclopropaneꢀcyclopentene rearrangeꢀ
ment, cyclopentene 3, independent of the amount of
9
—17
tinue.
Due to a possibility of the wide variation of reactivity
of DAC, it seemed interesting to study the behavior of
more complex carbon synthons, retaining however the
cyclopropane ring and the principle of spacing of donor
and acceptor substituents in the molecule. One of the most
simple representatives described earlier1
—8,18—21
is 2ꢀstyrylꢀ
cyclopropaneꢀ1,1ꢀdicarboxylate (2), for which, however,
no other types of transformations were known apart from
those characteristic of the most DAC of type 1, which
proceed with the generation of 1,3ꢀzwitterion. In this cases,
the styryl substituent served exclusively as a donor substitꢀ
GaCl . Since this reaction is a sigmatropic rearrangement
3
and does not require the formation of complex intermediꢀ
ates, it proceeds especially readily; gallium chloride actiꢀ
vates it through the coordination at the ester groups. At
room temperature and with an equimolar amount of
uent and was not directly involved in the transformaꢀ
tions.1
8—21
Suprisingly, but even simple and obvious vinylꢀ
cyclopropaneꢀcyclopentene rearrangment is not known for
DAC 2, and the corresponding cyclopentene 3 is not still
GaCl , cyclopentene 3 is formed almost in quantitative
3
described.2
2—26
In the present work, we realized the concept
yield. When a catalytic amount of GaCl is used, another
3
of "extended" reactivity of 2 with the involvement of its
double bond in different transformations and in detail studied
transformations of cyclopropane 2 upon treatment with
different Lewis acids, first of all, in dimerization processes.
isomer, diene 4, is also formed together with cyclopentene
3, but only in 20% yield (Scheme 2).
Scheme 2
Results and Discussion
Styrylcyclopropanedicarboxylate 2 was synthesized
from transꢀcinnamic aldehyde according to a well workꢀ
ing twoꢀstep procedure which includes Knoevenagel conꢀ
2
7,28
densation and Corey—Chaykovsky cyclopropanation.
Already first experiments on the transformations of
DAC 2 upon treatment with different Lewis acids showed
that actually no dimeric products were formed. In a numꢀ
ber of cases, there were no reactions at all, in other cases
Reagents and conditions: i. GaCl3 (100 mol.%), 25 °C, 1 h,
CH Cl ; ii. GaCl (20 mol.%), 25 °C, 1 h, CH Cl .
2
2
3
2
2
The deeper process occured upon reflux of 2 in orthoꢀ
dichlorobenzene (180 °C). In this case, substituted phenol
5 was isolated as the major product, the yield of which was
only ~45% because of a large amount of oligomers. It
turned out that initially cyclopropane 2 isomerizes to
cyclopentene 3, which at high temperature undergoes
transformation to phenol 5 (Scheme 3). In fact, subjectꢀ
ing cyclopentene 3 to similar conditions we obtained the
the reactions led exclusively to vinylcyclopropaneꢀcycloꢀ
pentene rearrangement2
2—26
with the formation of 2ꢀphenylꢀ
cyclopentꢀ3ꢀeneꢀ1,1ꢀdicarboxylate (3). In some cases
oligomerization occurred, especially when more drastic
conditions were used. We unsuccessfully tested all the
available arsenal of Lewis acids commonly used in DAC
chemistry: SnCl , TiCl , AlCl , EtAlCl , BF •Et O,
4
4
3
2
3
2

2
630
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016
Novikov et al.
Scheme 3
i. GaCl (100 mol.%), 180 °C, 8 h, oꢀDCB; ii. Ring opening; iii. Aromatization; iv. Hydrolysis.
3
same result as with cyclopropane 2, i.e., the fiveꢀmemꢀ
bered ring in cyclopentenedicarboxylate 3 treated with
leads to polysubstituted cyclopentane 6 and bicycloꢀ
[3.3.0]octane 7 (with an equimolar amount of GaCl , the
3
GaCl can undergo opening, that is a very rare example of the
reaction stops in the step of the formation of cyclopentene 3).
Since these reactions are quite simple and do not require
many steps, compounds 6 and 7 are formed as mixtures of
diastereomers, with cyclopentane 6, depending on the
conditions, being obtained as a mixture of from two to
four diastereomers (from eight possible), which can be
successfully separated. Bicyclooctane 7 is formed more
selectively as a mixture of only two diastereomers in the
ratio of ~1.5 : 1.
3
"
donorꢀacceptor cyclopentane". A plausible mechanism
of transformation of 3 to phenol 5 is given in Scheme 3.
The second, more interesting group of transformations
of cyclopropane 2 treated with gallium trichloride is the
dimerization reactions, which can be successfully carried
out only at reduced temperatures. The reaction result conꢀ
siderably depends on conditions of the process and someꢀ
times considerably changes even at their insignificant variꢀ
ations. Many of these processes proceed as complicated
cascade reactions with the formation of bicyclic structures
with many stereocenters, which, nonetheless, are formed
with exclusively high diastereoselectivity. Unfortunately,
the complicated character of proceeding processes plays
also a considerable negative role, since they are interfered
by a number of side processes. The most frequent of them
is the readily proceeding vinylcyclopropaneꢀcyclopentene
rearrangement to cyclopentene 3, always present in the
reaction mixtures. Another dominating side process is
oligomerization and polymerization reactions proceeding
even at quite low temperatures. This results in the formaꢀ
tion of a mixture of compounds and difficulties with their
isolation, that, nonetheless, is largely compensated by the
high complexity of assembling structures and very high
diastereoselectivity (up to the formation of a single diaꢀ
stereomer at a simultaneous formation of six stereocenters
in one process). The main directions of the transformaꢀ
tion of DAC 2 (disregarding the side processes) and conꢀ
ditions required for them to proceed are given in Scheme 4.
Let us consider these processes in more details. Two
quite routine dimerization processes predominantly proꢀ
ceed in the temperature range from –30 °C to 0 °C when
At a temperature near –80 °C and with an equimolar
amount of GaCl , bicyclic structures 8 and 9 are formed,
3
with the latter containing a chlorine atom in the sixꢀmemꢀ
bered ring (see Scheme 4). The reaction reached compleꢀ
tion within 9 h and leads to the formation of compounds 8
and 9 approximately in the equal ratio, which can be easily
separated by chromatography on SiO . Different amounts
2
of cyclopentene 3 and isomeric dimers 6 were also isolated
together with these compounds.
When using nonꢀoptimal conditions, the reaction
leads, apart from compounds 8 and 9, to a quite selective
formation of chlorineꢀcontaining bicyclo[3.3.0]octane 10
or dimer 11 with the structure rarely encountered in thisꢀ
type processes which contains a cyclobutane ring and an
exocyclic double bond (see Scheme 4). Both compounds
are obtained only in very narrow range of conditions. Thus,
especially low temperature (–95 °C) is required for the
formation of chloride 10, while dimer 11 is formed at
–80 °C, but when 50 mol.% of GaCl is used.
3
Note that compounds 8—11 are formed as a result of
complex multiꢀstep and not very obvious processes, and
all of them are formed as the only regioꢀ and diastereomer
despite the fact that up to six stereocenters are simultaꢀ
neously generated in one process. Apart from that, comꢀ
pounds 9 and 10 together with the fragments of cycloꢀ
propanes 2 additionally have a chlorine atom borrowed
from the Lewis acid, that is also quite unusual for the
using 20 mol.% of GaCl : a formal [3+2] cycloaddition
3
reaction of one molecule of DAC 2 as a classic 1,3ꢀzwitteꢀ
rion to the double bond of the second molecule of cycloꢀ
propane 2 or of the formed from it cyclopentene 3. This

GaCl ꢀMediated cascade dimerization
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016 2631
3
Scheme 4
Reagents and conditions: i. GaCl (20 mol.%), –30 °C, 1 h, CH Cl ; ii. GaCl (20 mol.%), 0 °C, 1 h, CH Cl ; iii. GaCl (100 mol.%),
3
2
2
3
2
2
3
–
95 °C, 8 h, CH Cl ; iv. GaCl (50 mol.%), –80 °C, 8 h, CH Cl ; v. GaCl (100 mol.%), –80 °C, 9 h, CH Cl .
2 2 3 2 2 3 2 2
Notes. a One diastereomer. b One isomer.
reactions of DAC with gallium chloride. Note that the
chlorine atom in the product also has a strictly fixed conꢀ
figuration. Unfortunately, the yields of the dimeric comꢀ
pounds 8—11 are not very high, but this is fully compenꢀ
sated by a certain complexity of the structures obtained
from simple and available cyclopropanedicarboxylate 2.
Apart from that major products of DAC 2 transformaꢀ
tion, in the temperature range from –40 to +10 °C we also
isolated and characterized a number of minor dimers 12—18
in the yields about 1.5—2%. The processes of their formaꢀ
tion are simpler than the cascade reactions described above,
while structurally they are either acyclic dimers, or differꢀ
ent products of formal [3+2] cycloaddition of 1,3ꢀzwitteꢀ
rion to different double bonds. Thus, compounds 12 and
13 correspond to a formal addition of the 1,3ꢀzwitterion
generated from one molecule of cyclopropane 2 to differꢀ
*
One diastereomer.

2
632
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016
Novikov et al.
tion of an unseparable mixture of diastereomers. Then, we
used the HSQC spectra to completely assign all the protoꢀ
nated carbon atoms. The final and the most important
step in the establishing entire carbon skeleton of the moleꢀ
cule was carried out using the HMBC spectra based on the
analysis of remote C—H constants through two and three
bonds. From the HMBC spectra, we extracted all the data
on the presence of these constants and used them to build
a graph from the atoms, which had an unambiguous soluꢀ
tion for fitting of all the observed constants, since in the
HMBC spectra a large amount of interactions is observed
(
due to the presence of a large number of different protons
in the structures), which several times duplicate and verify
each other. As a result, we obtained an unambiguous and
well confirmed structure of the studied compound. This is
the reason why the highꢀquality 2D spectra with a high
signal/noise ratio were required.
ent double bonds of (4ꢀphenylbutaꢀ1,3ꢀdienyl)malonate
formed from another cyclopropane 2 molecule. Bicyclic
compound 14 is an analog of dimer 7 formed by the formal
[
5+2] cycloaddition reaction. Compounds 15—17 are disꢀ
tinguished by the formation of an alkylidenemalonate fragꢀ
ment, that is quite characteristic of the threeꢀmembered
ring opening in type 1 DAC upon treatment with GaCl3
For example, the CH group containing a phenyl subꢀ
stituent was unambiguously determined from two correlaꢀ
tions in the HMBC: HCaliph — HCoꢀPh (direct and reꢀ
verse) and the interaction of the neighboring HCaliph with
CipsoꢀPh. The CH at the ester groups and the points of their
attachment (from the HCaliph — C=O correlations) were
determined similarly. The quaternary C atoms, their
assignment, and points of attachment were also deterꢀ
mined from the set of correlations in the HMBC. The
locations of the addition of chlorine atoms were deterꢀ
mined in the final step from the incomplete skeleton of the
molecule based on the combination of all the 2D experiꢀ
ments, while their introduction into the structure was
unambiguously confirmed by the HRMS data.
The final step in the structural analysis was the assignꢀ
ment of configuration for all the stereocenters in the molecule.
This was made using the 2D NOESY spectra by the analysis
of the crossꢀpeaks and identification of spatially close proꢀ
tons based on the NOE effect. The presence of a large
number of protons in the structures, their rigid polycyclic
structure, and, as a consequence, the presence of a large
number of crossꢀpeak in the NOESY made the configuraꢀ
tional analysis very simple, nonproblematic, and accurate,
which allowed us to unambiguously find relative configuꢀ
rations of all the stereocenters in the molecule. Apart from
that, the NOESY data well enough doubleꢀcheck and
verify the skeleton and the structure established previously.
As an example, Fig. 1 shows some key interactions in
the NOESY and HMBC spectra for compounds 9—11,
which were used to establish carbon skeletons and configꢀ
urations of substituents.
(
see Refs 9, 16, 17, and 29—32).
Note that none of the isolated compounds contained
fragments, in which the phenyl substituent would have
been involved, i.e., the electrophilic substitution left it inꢀ
tact, though for arylcyclopropanedicarboxylates this proꢀ
9
,13,15—17,29,31
cess occurs upon treatment with both GaCl
and other Lewis acids.9
3
—12
The methods used for determination of structures of
formed compounds should be discussed separately, since
this turned out to be a nontrivial problem, taking into
account their complicated character and nonobviousness
of formation. Since all the dimeric compounds, despite of
double purification by chromatography on SiO , were
2
heavy oils without any hope for crystallization, it was imꢀ
possible to use Xꢀray diffraction analysis. In this connecꢀ
tion, the structures were analyzed based on the combinaꢀ
1
13
tion of H and C NMR spectra, using 2D experiments
COSY, TOCSY, NOESY, HSQC, and HMBC. For the
dimers isolated in small amounts, we used a long acquisiꢀ
tion time, up to several days. Molecular formulas were
confirmed by high resolution mass spectrometry.
We used the following strategy for establishing the
structures. First, the COSY and TOCSY spectra were used
to find all the proton spin systems and establish fragments
of molecular skeleton consisting of the protonꢀcontaining
C atoms. In the proton spectra, the CH groups (in which
2
both protons are always nonequivalent and usually have
individual chemical shifts) was distinguished from the CH
groups using the editedꢀHSQC or HSQC+DEPTꢀ135.
The signals of all overlapped protons were also distinꢀ
guishable and were assigned using 2D spectra. In this case,
the TOCSY spectra were found to be very useful, since the
proton spin systems in the dimers are quite long and some
interactions can be lost in the COSY spectra. Apart from
that, TOCSY allows one to unambiguously distinguish the
spin systems of separate components in the case of isolaꢀ
As to the possible mechanism of transformations, we
should note that the "highꢀtemperature" processes (above
–30 °C) are mainly represented by a typical for DAC forꢀ
1
—9,18—21
mal [3+2] cycloaddition
of 1,3ꢀzwitterion 19 to
the double bonds of the starting or formed compounds.
Here, two principal processes are observed: the reaction of
zwitterion 19 with the second molecule of the starting
cyclopropane 2 or cyclopentene 3 formed from it (Scheme 5,

GaCl ꢀMediated cascade dimerization
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016 2633
3
NOE
NOE
NOE
9
10
11
HMBC
HMBC
HMBC
9
10
11
Fig. 1. Key interactions in the NOESY and HMBC spectra of compounds 9—11.
Note. Fig. 1 is available in full color on the web page of the journal (http://www.linkspringer.com).
Scheme 5
E = CO Me
2
Note. 1.3ꢀZwI is a classic 1,3ꢀzwitterion, 1,5ꢀZwI is a 1,5ꢀzwitterion.

2
634
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016
Novikov et al.
the main directions are shown in blue). Minor directions
are also versions of formal [3+2] cycloaddition, but already
with the isomeric diene 4. In this case, the cyclization of
The cascade processes at the temperatures around
–80 °C also proceed through the initial generation of the
gallium complex 19 (Scheme 6), however, further proꢀ
cesses are more complicated and have at least three indeꢀ
pendent cascade chains, in one of which the branching
1
,5ꢀzwitterion 20 is accompanied by the hydride shift with
the formation of substituted octaꢀ1,3,7ꢀtriene 16.
Scheme 6
E = CO Me
2
Note. [3+2] is the [3+2] cycloaddition.

GaCl ꢀMediated cascade dimerization
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016 2635
3
occurs only in the last step, with all of them being new and
original. Moreover, all the processes proceed with clearly
preset stereochemistry leading to the formation of the only
diastereomer despite of the formation of several stereoꢀ
centers.
Thus, the formation of the bicyclo[3.3.0]octane fragꢀ
ment of compounds 8 and 10 occurs via the reaction of
two zwitterions 19 and two subsequent carbocationic cyclꢀ
izations with the formation of two fused fiveꢀmembered
rings. Only the last step is different: dimer 8 is formed
through the elimination of a proton and the double bond
migration, while dimer 10 through the chloride anion
addition.
formation of original cyclic structures. In these reactions,
the reaction centers of the styryl substituent were effiꢀ
ciently involved, which has not been done earlier for such
a cyclopropane. Many compounds, despite the formation
of several stereocenters, were obtained as the only diaꢀ
stereomer. A chlorine atom was introduced into some
structures, that increased their functionality. The formaꢀ
tion of a cyclobutane ring in one of the dimers is also
interesting, since such cycles are formed extremely rare in
similar reactions and are a unique type of the DAC reacꢀ
tivity. The only disadvantage of this range of reactions are
the low yields of the dimeric products, caused by the ready
proceeding of intramolecular rearrangement to cycloꢀ
pentenedicarboxylate 3 and oligomerization processes.
However, the low yields are partially compensated by the
oneꢀpot assembling the final structures and very high diaꢀ
stereoselectivity. This variety of the processes efficiently
demonstrates importance of our new approaches to the
diversification of the DAC reactivity types and leads to the
development of new chemistry of this interesting class of
compounds.
The bicyclo[4.3.0]nonane structure 9 is formed from
dimer 6, which is actually yet another donorꢀacceptor
cyclopropane. First, its treatment with GaCl leads to the
3
cyclopropane ring opening and a key 1,2ꢀzwitterionic galꢀ
lium complex 21 is generated after the proton migration,
which then cyclizes with the formation of the sixꢀmemꢀ
bered ring (Scheme 6). The formation of intermediate 21
is confirmed by the isolation of its "decomplexed" form 15
as one of the minor products.
The fact of the formation of bicyclic dimer 11 containꢀ
ing a cyclobutane ring is very interesting. Generally speakꢀ
ing, it is not typical of the reactions involving DAC to give
cyclobutanes, and the formation of compound 11 is a rare
example. This pathway suggests the formation of a key
Experimental
1H and 13C NMR spectra were recorded on Bruker AMXꢀIII
00 (400.1 and 100.6 MHz, respectively) and Bruker AVANCE
4
II 300 spectrometer (300 and 75 MHz, respectively) for soluꢀ
tions in CDCl3 containing 0.05% of Me4Si as an internal stanꢀ
dard. Assignment of signals and determination of isomeric comꢀ
position of compounds were carried out using homoꢀ and heteroꢀ
nuclear 1D and 2D correlation spectra: 1D DEPTꢀ135, 2D
COSY, TOCSY, NOESY, HSQC, editedꢀHSQC and HMBC.
IR spectra were recorded on a FTꢀIR spectrometer in solution of
1
,2ꢀzwitterionic gallium complex 22, which then reacts
with the second molecule of the starting cyclopropane 2
with the intramolecular cyclization at the styryl double
bond. After opening of the second cyclopropane ring, the
second annulated fiveꢀmembered ring is formed. The reacꢀ
tion conditions should not be too drastic in order not to
open the cyclobutane ring formed. The last step, that
is the proton migration to the malonyl fragment, forms
the exoꢀcyclic double bond with the Eꢀconfiguration of
substituents; the low temperature of the reaction helps to
avoid its isomerization to more favorable endoꢀcyclic
double bond.
CHCl (0.5—2%). High resolution mass spectra (HRMS) were
recorded using electrospray ionization (ESI). Thinꢀlayer chroꢀ
3
33
matography was carried out on Merck Silufol chromatographic
plates. Merck silica gel 60 (0.040—0.063 mm) was used for
preparative chromatography. Anhydrous GaCl3 was purchased
from Aldrich, all the manipulations with it were carried out
under anhydrous argon. The solvents of the reagent grade qualiꢀ
ty (>99.5%) were used without additional purification. Dichloroꢀ
methane for the work with GaCl3 was first maintained over
granulated KOH and then distilled over P O under anꢀ
Special attention should be paid to compounds 9
and 11, the formation of which requires involvement of
2
5
1
,2ꢀzwitterionic gallium complexes 21 and 22, which are
hydrous argon.
17,29—32
new examples of 1,2ꢀzwitterionic reactivity of DAC.
Synthesis of compounds 3—11 (general procedure). Anhyꢀ
drous gallium chloride was added to a solution of styrylmalonate 2
(200 mg, 0.678 mmol) in anhydrous dichloromethane (7.5 mL)
under argon and the reaction mixture was stirred according to
the conditions indicated in Schemes 2 or 4. All the conditions
should be strictly followed. Then, a 5% solution of hydrochloric
acid (5 mL) was added to the reaction mixture, which was exꢀ
tracted with dichloromethane (3×10 mL). The combined organic
phases were dried with anhydrous MgSO4 and the solvent was
evaporated in vacuo. The obtained compounds were isolated and
additionally purified using column and/or thinꢀlayer chromatoꢀ
graphy, using mixtures of benzene and ethyl acetate in different
ratios as an eluent. If necessary, a cascade of several sequential
A possibility of this type of transformations is provided by
a specific feature of GaCl to act as a Lewis acid, which
3
was successfully used for styrylcyclopropane 2, as well
(
see Scheme 6).
In conclusion, we for the first time accomplished and
studied in detail the dimerization of 2ꢀstyrylcyclopropaneꢀ
,1ꢀdicarboxylate upon treatment with gallium trichlorꢀ
1
ide. Using a fine variation in the reaction conditions, we
successfully developed and effected a wide range of casꢀ
cade dimerization processes including generation and
transformation of different carboꢀcenters, leading to the

2
636
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016
Novikov et al.
1
3
chromatographic procedures was used for separation of diastereoꢀ
mers and isolation of pure compounds.
(m, 1 H, H , CH ). C NMR (100.6 MHz, CDCl ), δ: 172.7,
b 2 3
170.8, 170.5 and 168.6 (4 COO), 140.9 and 137.4 (2 ipsoꢀPh),
131.4 and 130.1 (HC=CH), 128.8, 128.7, 128.0, 127.9, 126.4
and 126.2 (2 Ph), 64.8 (C), 57.0 (C(2)), 53.0, 52.7, 52.2 and 51.9
(4 OMe), 48.8 (C(4)), 47.7 (C(3)), 40.5 (C(5)), 32.5 (CH),
Dimethyl 2ꢀphenylcyclopentꢀ3ꢀeneꢀ1,1ꢀdicarboxylate (3).
1
The yield was 97%. A heavy colorless oil. H NMR (400 MHz,
CDCl ), δ: 7.28—7.14 (m, 5 H, Ph); 5.86 (ddd, 1 H, =CH,
3
J = 5.8 Hz, J = 4.4 Hz, J = 2.2 Hz); 5.69 (dq, 1 H, =CH,
J = 5.8 Hz, J = 2.2 Hz); 4.89 (br.s, 1 H, CH); 3.75 (s, 3 H,
OMe); 3.47 (ddd, 1 H, H , CH , J = 17.5 Hz, J = 4.7 Hz,
29.0 (C), 19.3 (CH ). HRMS (ESI), found: m/z 543.1981;
2
+
C30H32NaO ; calculated: 543.1989 [M + Na] .
8
Tetramethyl (3RS),3aSR,4SR,6aSRꢀ and tetramethyl
(3SR),3aSR,4SR,6aSRꢀ4ꢀphenylꢀ3ꢀ(E)ꢀstyrylhexahydropentalꢀ
eneꢀ1,1,5,5ꢀtetracarboxylate (7). The yield was 27%. A mixture
of diastereomers (the ratio of 1.5 : 1). A heavy colorless oil. IR
a
2
J = 2.4 Hz); 3.08 (s, 3 H, OMe); 2.82—2.74 (m, 1 H, H , CH ).
b
2
Dimethyl 2ꢀ((1E,3E)ꢀ4ꢀphenylbutaꢀ1,3ꢀdienꢀ1ꢀyl)malonate
4). The yield was 20%. A heavy colorless oil. 1H NMR
(
–
1
(
400 MHz, CDCl ), δ: 7.41—7.20 (m, 5 H, Ph); 6.78 (dd, 1 H,
(CHCl ), ν/cm : 3021, 2954, 2928, 2847, 2401, 1729, 1602,
3
3
–
1
H(3), J = 15.7 Hz, J = 10.4 Hz); 6.57 (d, 1 H, H(4), J = 15.7 Hz);
.38 (dd, 1 H, H(2), J = 15.3 Hz, J = 10.4 Hz); 5.99 (dd, 1 H,
H(1), J = 15.3 Hz, J = 9.0 Hz); 4.14 (d, 1 H, CH, J = 9.0 Hz);
1496, 1455, 1436, 1272, 1224 cm . HRMS (ESI), found: m/z
+
6
543.1981; C30H32NaO ; calculated: 543.1989 [M + Na] .
8
1
Major diastereomer. H NMR (400 MHz, CDCl ), δ:
3
3
.76 (s, 6 H, 2 OMe).
Methyl 2ꢀhydroxyꢀ1,1´ꢀbiphenylꢀ3ꢀcarboxylate (5). The yield
7.34—6.95 (m, 10 H, 2 Ph); 6.04 (d, 1 H, =CH, J = 15.7 Hz);
5.84 (dd, 1 H, =CH, J = 15.7 Hz, J = 7.8 Hz); 3.88 (d, 1 H,
H(4), J = 11.8 Hz); 3.84, 3.75, 3.74 and 2.99 (all s, 12 H,
–
1
was 45%. A heavy colorless oil. IR (CHCl ), ν/cm : 3036, 3033,
3
3
1
021, 3013, 2955, 2874, 1729, 1674, 1614, 1495, 1454, 1441,
4 OMe); 3.00—2.91 (m, 1 H, H (2)); 2.83—2.74 (m, 1 H,
a
1
329, 1285, 1284, 1234. H NMR (400.1 MHz, CDCl ), δ: 11.27
H(6a)); 2.72—2.62 (m, 1 H, H(3a)); 2.66—2.58 (m, 1 H,
H (2)); 2.56—2.47 (m, 2 H, H(3) and H (6)); 2.33—2.25
3
(
s, 1 H, OH); 7.86 (dd, 1 H, H(4) or H(6), J = 7.9 Hz, J = 1.6 Hz);
.61—7.55 (m, 2 H, oꢀPh); 7.52 (dd, 1 H, H(6) or H(4),
J = 7.5 Hz, J = 1.6 Hz); 7.47—7.39 (m, 2 H, mꢀPh); 7.39—7.31
m, 1 H, pꢀPh); 6.98—6.91 (dd, 1 H, H(5), J = 7.9 Hz,
b
a
13
7
(m, 1 H, H (6)). C NMR (100.6 MHz, CDCl ), δ: 172.7,
b
3
172.5, 170.2 and 169.3 (4 COO), 138.0 and 137.6 (2 ipsoꢀ
Ph), 131.7 and 130.0 (HC=CH), 128.8, 128.5, 128.1 and
126.3 (4 oꢀPh and 4 mꢀPh), 127.3 and 127.1 (2 pꢀPh), 71.0
(C(5)), 57.7 (C(1)), 56.2 (C(3a)), 54.6 (C(6a)), 52.9, 52.8,
52.5 and 52.1 (4 OMe), 51.8 (C(4)), 45.5 (C(2)), 33.5 (C(6)),
33.3 (C(3)).
(
13
J = 7.5 Hz); 3.98 (s, 3 H, OMe). C NMR (100.6 MHz, CDCl ),
δ: 170.1 (COO), 158.9 (C(2)), 137.1 (ipsoꢀPh), 136.6 and 128.9
3
(
1
C(4) and C(6)), 130.4 and 112.5 (C(1) and C(3)), 128.8 (oꢀPh),
28.0 (mꢀPh), 127.8 (pꢀPh), 119.0 (C(5)), 52.2 (OMe). HRMS
(
[
ESI), found: m/z 251.0674; C14H12NaO ; calculated: 251.0679
M + Na] .
Minor diastereomer. 1H NMR (400 MHz, CDCl ), δ:
3
3
+
7.34—6.95 (m, 10 H, 2 Ph); 6.08—6.05 (m, 2 H, HC=CH); 3.84,
3.76, 3.72, 3.01 (all s, 12 H, 4 OMe); 3.83 (d, 1 H, H(4),
Dimethyl
2SR,3RS,4SR)ꢀ3ꢀ[(SR)ꢀ2,2ꢀbis(methoxycarbonyl)cyclopropyl]ꢀ
ꢀphenylꢀ4ꢀ(E)ꢀstyrylcyclopentaneꢀ1,1ꢀdicarboxylate (6). The
(2SR,3RS,4SR)ꢀ3ꢀ[(RS)ꢀ
and
dimethyl
(
2
J = 12.5 Hz); 3.35 (dd, 1 H, H (2), J = 14.8 Hz, J = 8.0 Hz);
a
2.97—2.89 (m, 1 H, H(3a)); 2.82—2.76 (m, 1 H, H(3));
yield was 27%. The ratio of diastereomers 3 : 1.
2.56—2.45 (m, 2 H, H(6a) and H (6)); 2.35—2.25 (m, 2 H,
H (2) and H (6)). C NMR (100.6 MHz, CDCl ), δ: 173.1,
b b 3
a
13
Major diastereomer. A heavy colorless oil. IR (CHCl ),
3
–1
–
1
ν/cm : 3021, 2954, 2849, 1730, 1496, 1437, 1262, 1225 cm
.
171.0, 170.7, 170.6 (4 COO), 138.1 and 137.7 (2 ipsoꢀPh), 131.8
and 129.0 (HC=CH), 128.5, 128.1, 128.0 and 126.4 (4 oꢀPh and
4 mꢀPh), 127.2 and 127.1 (2 pꢀPh), 70.2 (C(5)), 57.1 (C(1)),
54.5 (C(3a)), 53.0, 52.8, 52.7 and 52.0 (4 OMe), 43.1 (C(6a)),
48.7 (C(4)), 45.3 (C(2)), 36.9 (C(3)), 33.3 (C(6)).
1
H NMR (400.1 MHz, CDCl ), δ: 7.42—7.08 (m, 10 H, 2 Ph);
3
6.52 (d, 1 H, =CH, J = 15.8 Hz); 6.21 (dd, 1 H, =CH, J = 15.8 Hz,
J = 7.8 Hz); 4.13 (d, 1 H, H(2), J = 6.6 Hz); 3.78, 3.67, 3.09,
2
.86 (all s, 12 H, 4 OMe); 2.74—2.61 (m, 1 H, H(4)); 2.42—2.34
(
m, 2 H, H C(5)); 2.36—2.25 (m, 1 H, CH); 2.01 (td, 1 H, H(3),
Dimethyl (1SR,3aRS,6aRS)ꢀ1ꢀ[3ꢀmethoxyꢀ2ꢀ(methoxycarbꢀ
onyl)ꢀ3ꢀoxopropyl]ꢀ5,6ꢀdiphenylꢀ3,3a,4,6aꢀtetrahydropentaleneꢀ
2,2(1H)ꢀdicarboxylate (8). The yield was 19%. A heavy colorless
2
J = 9.7 Hz, J = 6.6 Hz); 1.49 (dd, 1 H, H , CH , J = 8.1 Hz,
a
2
J = 4.9 Hz); 1.34 (dd, 1 H, H , CH , J = 9.3 Hz, J = 4.9 Hz).
b
2
13
–1
C NMR (100.6 MHz, CDCl ), δ: 172.7, 170.4, 169.5 and 168.6
oil. IR (CHCl ), ν/cm : 3021, 2955, 2848, 2401, 1731, 1495,
3
3
(
4 COO), 141.1 and 137.2 (2 ipsoꢀPh), 131.6 and 130.9 (HC=CH),
1436, 1267, 1225 cm–1. 1H NMR (400.1 MHz, CDCl ), δ:
3
1
5
29.3, 128.7, 128.0, 127.5, 127.0 and 126.3 (2 Ph), 66.2 (C(1)),
6.4 (C(2)), 53.2, 52.6, 52.0 and 51.9 (4 OMe), 50.9 (C(3)), 48.5
7.28—7.00 (m, 10 H, 2 Ph); 3.73, 3.68, 3.57, 3.55 (all s, 12 H,
4 OMe); 3.54—3.48 (m, 1 H, H(6a)); 3.20—3.10 (m, 1 H, H(3a));
(
(
[
C(4)), 40.6 (C(5)), 34.0 (CH), 32.1 (C), 20.7 (CH ). HRMS
3.14 (t, 1 H, CH), J = 7.2 Hz); 3.00 (ddq, 1 H, H (4), J = 16.6 Hz,
2
a
ESI), found: m/z 543.1975; C30H32NaO ; calculated: 543.1989
J = 9.3 Hz, J = 1.4 Hz); 2.73 (m, 1 H, H (4)); 2.72 (dd, 1 H,
8
b
+
M + Na] .
H (3), J = 13.5 Hz, J = 8.3 Hz); 2.63 (dd, 1 H, H(1), J = 12.8 Hz,
a
Minor diastereomer. A heavy colorless oil. IR (CHCl ),
J = 7.1 Hz); 2.14 (dd, 1 H, H (3), J = 13.5 Hz, J = 7.1 Hz);
3
b
ν/cm–1: 3021, 2953, 2852, 1731, 1496, 1437 cm
–1
.
1
H NMR
1.92—1.77 (m, 2 H, CH ). C NMR (100.6 MHz, CDCl ),
13
2
3
(
=
400 MHz, CDCl ), δ: 7.37—7.11 (m, 10 H, 2 Ph); 6.51 (d, 1 H,
CH, J = 15.7 Hz); 6.05 (dd, 1 H, =CH, J = 15.7 Hz,
δ: 171.9, 171.1, 169.7 and 169.5 (4 COO), 139.8 (C(8)), 137.8,
137.5 (2 ipsoꢀPh), 136.6 (C(5)), 129.1, 128.2 (4 oꢀPh), 128.5,
127.9 (4 mꢀPh), 126.9 and 126.8 (2 pꢀPh), 65.1 (C(2)), 63.1
(C(6a)), 52.8, 52.5, 52.4 and 52.4 (4 OMe), 49.8 (CH), 47.9
3
J = 8.4 Hz); 4.12 (d, 1 H, H(2), J = 10.9 Hz); 3.74, 3.66, 3.00,
.99 (all s, 12 H, 4 OMe); 2.87 (dd, 1 H, H (5), J = 13.6 Hz,
2
a
J = 12.0 Hz); 2.63—2.53 (m, 1 H, H(3)); 2.27—2.16 (m, 2 H,
(C(1)), 44.5 (C(3a)), 42.3 (C(3)), 37.6 (C(3a)), 31.8 (CH ).
2
H (5) and H(4)); 1.83 (td, 1 H, CH, J = 9.7 Hz, J = 8.4 Hz);
HRMS (ESI), found: m/z 543.1979; C30H32NaO ; calculated:
543.1989 [M + Na] .
a
8
+
1
.02 (dd, 1 H, H , CH ), J = 9.7 Hz, J = 4.9 Hz); 0.94—0.87
a
2

GaCl ꢀMediated cascade dimerization
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016 2637
3
Dimethyl (1RS,3aSR,4RS,5SR,6RS,7aSR)ꢀ4ꢀchloroꢀ6ꢀ(1,3ꢀ
dimethoxyꢀ1,3ꢀdioxopropanꢀ2ꢀyl)ꢀ1,5ꢀdiphenyloctahydroꢀ2Hꢀinꢀ
deneꢀ2,2ꢀdicarboxylate (9). The yield was 20%. A heavy colorꢀ
40.4 (C(5)), 32.8 (CH ), 30.0 (C(4)). HRMS (ESI), found:
2
+
m/z 543.1981; C30H32NaO ; calculated: 543.1989 [M + Na] .
8
–
1
less oil. IR (CHCl ), ν/cm : 3065, 3020, 2955, 2930, 2850,
This work was financially supported by the Russian
Science Foundation (Project No. 14ꢀ13ꢀ01054).
3
400, 1728, 1602, 1496, 1455, 1455, 1436, 1273, 1224 cm–
1
.
2
1
H NMR (400 MHz, CDCl ), δ: 7.42—7.16 (m, 10 H, 2 Ph);
3
4
.00 (dd, 1 H, H(4), J = 10.9 Hz, J = 10.3 Hz); 3.90 (d, 1 H,
References
H(1), J = 12.3 Hz); 3.75, 3.65, 3.50, 3.04 (all s, 12 H, 4 OMe);
3
.12 (d, 1 H, CH, J = 3.3 Hz); 2.91 (dd, 1 H, H(5), J = 11.8 Hz,
J = 10.3 Hz); 2.66 (dd, 1 H, H (3), J = 13.8 Hz, J = 12.0 Hz);
1. H. U. Reissig, R. Zimmer, Chem. Rev., 2003, 103, 1151.
2. M. Yu, B. L. Pagenkopf, Tetrahedron, 2005, 61, 321.
3. F. de Simone, J. Waser, Synthesis, 2009, 41, 3353.
4. C. A. Carson, M. A. Kerr, Chem. Soc. Rev., 2009, 38, 3051
5. M. J. Campbell, J. S. Johnson, A. T. Parsons, P. D. Pohlꢀ
haus, S. D. Sanders, J. Org. Chem., 2010, 75, 6317.
6. M. Y. Melnikov, E. M. Budynina, O. A. Ivanova, I. V. Trushꢀ
kov, Mendeleev Commun., 2011, 21, 293.
a
2
.54 (dd, 1 H, H (3), J = 13.8 Hz, J = 7.0 Hz); 2.49 (dddd, 1 H,
b
H(6), J = 12.2 Hz, J = 11.8 Hz, J = 3.5 Hz, J = 3.3 Hz); 2.18
dddd, 1 H, H(7a), J = 12.3 Hz, J = 12.2 Hz, J = 12.0 Hz,
(
J = 3.0 Hz); 1.94 (dddd, 1 H, H(3a), J = 12.2 Hz, J = 12.0 Hz,
J = 10.9 Hz, J = 7.0 Hz); 1.88 (ddd, 1 H, H (7), J = 13.0 Hz, J =
a
3
.5 Hz, J = 3.0 Hz); 1.39 (ddd, 1 H, H (7), J = 13.0 Hz,
b
13
J = 12.2 Hz, J = 12.0 Hz). C NMR (100.6 MHz, CDCl ), δ:
3
1
1
6
5
4
5
72.9, 171.1, 169.1, 168.5 (4 COO), 140.1 and 137.6 (2 ipsoꢀPh),
28.8 and 128.3 (4 oꢀPh and 4 mꢀPh), 127.7 and 127.3 (2 pꢀPh),
8.2 (C(4)), 64.4 (C(2)), 56.2 (C(1)), 55.8 (C(5)), 52.9, 52.4,
2.2 and 52.2 (4 OMe), 52.7 (C(3a)), 51.7 (CH), 46.7 (C(7a)),
4.1 (C(6)), 39.2 (C(3)), 30.5 (C(7)). HRMS (ESI), found: m/z
7. T. F. Schneider, J. Kaschel, D. B. Werz, Angew. Chem., Int.
Ed., 2014, 53, 5504.
8. F. de Nanteuil, F. de Simone, R. Frei, F. Benfatti, E. Serraꢀ
no, J. Waser, Chem. Commun., 2014, 50, 10912.
9. R. A. Novikov, Y. V. Tomilov, Mendeleev Commun., 2015,
25, 1.
+
57.1950; C30H34ClO ; calculated: 557.1937 [M + H] .
8
Dimethyl (1SR,3aRS,4SR,5RS,6RS,6aRS)ꢀ4ꢀchloroꢀ1ꢀ[3ꢀ
methoxyꢀ2ꢀ(methoxycarbonyl)ꢀ3ꢀoxopropyl]ꢀ5,6ꢀdiphenylhexaꢀ
10. A. O. Chagarovskiy, O. A. Ivanova, E. M. Budynina,
I. V. Trushkov, M. Y. Melnikov, Tetrahedron Lett., 2011,
52, 4421.
11. O. A. Ivanova, E. M. Budynina, A. O. Chagarovskiy,
I. V. Trushkov, M. Y. Melnikov, J. Org. Chem., 2011,
76, 8852.
12. O. A. Ivanova, E. M. Budynina, A. O. Chagarovskiy, E. R.
Rakhmankulov, I. V. Trushkov, A. V. Semeykin, N. L.
Shimanovskii, M. Y. Melnikov, Chem. Eur. J., 2011,
17, 11738.
hydropentaleneꢀ2,2(1H)ꢀdicarboxylate (10). The yield was 14%.
–
1
A heavy colorless oil. IR (CHCl ), ν/cm : 3064, 3032, 3025,
3
3
1
7
015, 2955, 2847, 1730, 1602, 1495, 1437, 1272, 1235, 1235,
229, 1222, 1211 cm–1
.
1
H NMR (300 MHz, CDCl ), δ:
3
.42—7.04 (m, 10 H, 2 Ph); 3.76, 3.75, 3.73, 3.62 (all s, 12 H, 4
OMe); 3.96 (dd, 1 H, H(4), J = 10.8 Hz, J = 9.5 Hz); 3.45—3.37
m, 1 H, CH); 3.41—3.31 (m, 1 H, H(5)); 3.29—3.15 (m, 1 H,
(
H(3a)); 3.20—3.11 (m, 1 H, H(6)); 2.90 (dd, 1 H, H (3),
a
J = 13.8 Hz, J = 8.4 Hz); 2.82—2.73 (m, 1 H, H(1)); 2.63—2.51
13. R. A. Novikov, V. A. Korolev, V. P. Timofeev, Y. V. Tomꢀ
ilov, Tetrahedron Lett., 2011, 52, 4996.
14. R. A. Novikov, V. P. Timofeev, Y. V. Tomilov, J. Org. Chem.,
2012, 77, 5993.
15. R. A. Novikov, Y. V. Tomilov, Helv. Chim. Acta, 2013,
96, 2068.
16. R. A. Novikov, A. V. Tarasova, Y. V. Tomilov, Mendeleev
Commun., 2015, 25, 341.
(
1
m, 1 H, H(6a)); 2.07—1.97 (m, 1 H, H (3)); 1.94—1.81,
b
.63—1.51 (both m, 2 H, CH2). 13C NMR (100.6 MHz, CDCl ),
3
δ: 172.2, 171.0, 169.9 and 169.5 (4 COO), 142.4 and 137.9
2 ipsoꢀPh), 128.7, 128.5 (4 mꢀPh), 127.8 and 127.7 (4 oꢀPh),
(
1
1
5
4
27.3, 126.8 (2 pꢀPh), 128.8, 128.17, 128.16, 127.9, 127.1 and
26.7 (2 pꢀPh), 70.2 (C(4)), 66.5 (C(5)), 66.1 (C(2)), 57.4 (C(6)),
6.1 (C(6a)), 52.9, 52.7, 52.5 and 52.4 (4 OMe), 51.6 (C(3a)),
9.9 (C(1)), 49.4 (CH), 39.5 (C(3)), 30.2 (CH ). HRMS (ESI),
17. R. A. Novikov, A. V. Tarasova, V. A. Korolev, V. P. Tiꢀ
mofeev, Y. V. Tomilov, Angew. Chem., Int. Ed., 2014,
53, 3187.
2
found: m/z 579.1757; C30H33ClNaO ; calculated: 579.1756
8
+
[
M + Na] .
Dimethyl (1RS,2RS,5SR,7RS)ꢀ3ꢀ((E)ꢀbenzylidene)ꢀ2ꢀ[3ꢀ
methoxyꢀ2ꢀ(methoxycarbonyl)ꢀ3ꢀoxopropyl]ꢀ7ꢀphenylbicycloꢀ
3.2.0]heptaneꢀ6,6ꢀdicarboxylate (11). The yield was 22%.
18. M. R. Vriesen, H. K. Grover, M. A. Kerr, Synlett, 2014,
25, 428.
19. R. Talukdar, A. Saha, D. P. Tiwari, M. K. Ghorai, Tetraꢀ
hedron, 2016, 72, 613.
20. I. S. Young, M. A. Kerr, Angew. Chem., Int. Ed., 2003,
42, 3023.
[
–
1
A heavy colorless oil. IR (CHCl ), ν/cm : 3036, 3011, 2955,
3
929, 2853, 1730, 1646, 1601, 1496, 1437, 1276, 1235 cm–
1
.
2
1
H NMR (400 MHz, CDCl ), δ: 7.40—7.15 (m, 10 H, 2 Ph);
3
6
.50 (s, 1 H, =CH); 3.93 (d, 1 H, H(7), J = 8.0 Hz); 3.73, 3.60,
21. A. T. Parsons, J. S. Johnson, J. Am. Chem. Soc., 2009,
131, 3122.
3.33, 3.14 (s, 12 H, 4 OMe); 3.61—3.58 (m, 1 H, H(5)); 3.51 (t, 1 H,
CH, J = 7.3 Hz); 3.03 (t, 1 H, H(1), J = 7.7 Hz); 2.84—2.75 (m,
H, H (4)); 2.55 (d, 1 H, H (4), J = 17.8 Hz); 2.48 (dd, 1 H,
22. H. M. L. Davies, G. Ahmed, R. L. Calvo, M. R. Churchill,
D. G. Churchill, J. Org. Chem., 1998, 63, 2641.
23. H. M. L. Davies, B. Hu, J. Org. Chem., 1992, 57, 4309.
24. D. F. Harvey, M. F. Brown, Tetrahedron Lett., 1991,
32, 2871.
25. H. M. L. Davies, B. Hu, J. Org. Chem., 1992, 57, 3186.
26. T. Hudlicky, N. E. Heard, A. Fleming, J. Org. Chem., 1990,
55, 2570.
1
a
b
H(2), J = 10.1 Hz, J = 6.0 Hz); 2.07—1.99 (m, 2 H, CH ).
2
13
C NMR (100.6 MHz, CDCl ), δ: 170.0, 169.9, 169.8 and
3
1
1
69.7 (4 COO), 145.8 (C(3)), 138.2 and 137.6 (2 ipsoꢀPh), 128.8,
28.17, 128.16, 127.9 (12 oꢀPh and 4 mꢀPh), 127.1 and 126.7
(
(
2 pꢀPh), 126.5 (=CH), 61.5 (C(6)), 52.7, 52.6, 52.2 and 52.0
4 OMe), 52.2 (C(2)), 50.1 (CH), 47.3 (C(7)), 41.9 (C(1)),

2
638
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016
Novikov et al.
2
2
2
3
3
7. E. J. Corey, M. Chaykovsky, J. Am. Chem. Soc., 1965,
7, 1353.
8. P. D. Pohlhaus, S. D. Sanders, A. T. Parsons, W. Li, J. S.
Johnson, J. Am. Chem. Soc., 2008, 130, 8642.
9. D. D. Borisov, R. A. Novikov, Y. V. Tomilov, Angew. Chem.,
Int. Ed., 2016, 55, 12233.
0. R. A. Novikov, A. V. Tarasova, Y. V. Tomilov, Synlett, 2016,
32. R. A. Novikov, D. O. Balakirev, V. P. Timofeev, Y. V. Tomꢀ
ilov, Organometallics, 2012, 31, 8627.
33. A. M. Tsedilin. A. N. Fakhrutdinov, D. B. Eremin, S. S.
Zalesskiy, A. O. Chizhov, N. G. Kolotyrkina, V. P. Ananikꢀ
ov, Mendeleev Commun., 2015, 25, 454.
8
2
7, 1367.
1. R. A. Novikov, A. V. Tarasova, V. A. Korolev, E. V. Shulꢀ
ishov, V. P. Timofeev, Y. V. Tomilov, J. Org. Chem., 2015,
Received September 23, 2016;
in revised form October 17, 2016
8
0, 8225.