Reaction of methyl 1-bromocyclopentanecarboxylate with zinc and 1-aryl-5-phenylpenta-1,4-dien-3-ones

Article abstract of DOI:10.1134/S107042801208009X

Methyl 1-bromocyclopentanecarboxylate reacted with zinc and 1-aryl-5-phenylpenta-1,4-dien-3-ones with the formation of isomeric 10-aryl-8-(2-arylethenyl)-7-oxaspiro[4.5]dec-8-en-6-ones. Pleiades Publishing, Ltd., 2012.

Full text of DOI:10.1134/S107042801208009X

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2012, Vol. 48, No. 8, pp. 1090−1093. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © N.F. Kirillov, P.A. Slepukhin, A.A. Gorbunov, A.G. Gavrilov, M.I. Vakhrin, 2012, published in Zhurnal Organicheskoi Khimii, 2012,
Vol. 48, No. 8, pp. 1093−1096.
Reaction of Methyl 1-Bromocyclopentanecarboxylate
with Zinc and 1-Aryl-5-phenylpenta-1,4-dien-3-ones
N. F. Kirillova, P. A. Slepukhinb, A. A. Gorbunovc, A. G. Gavrilova, and M. I. Vakhrina
aPerm State National Research University, Perm, 614990 Russia
e-mail: kirillov@psu.ru
bPostovskii Institute of Organic Synthesis, Ural Division, Russian Academy of Sciences,
Yekaterinburg, Russia
cInstitute of Technical Chemistry, Ural Division, Russian Academy of Sciences, Perm, Russia
Received October 15, 2011
Abstract—Methyl 1-bromocyclopentanecarboxylate reacted with zinc and 1-aryl-5-phenylpenta-1,4-dien-3-ones
with the formation of isomeric 10-aryl-8-(2-arylethenyl)-7-oxaspiro[4.5]dec-8-en-6-ones.
DOI: 10.1134/S107042801208009X
It has been formerly established that the acyclic
Reformatsky reagents react with symmetric 1,5-diaryl-
penta-1,4-dien-3-ones giving spiro-3,4-dihydropyran-
2-ones with an aryl substituent in the position 4 and
an arylethenyl substituent in the position 6 of the het-
erocycle [1]. In the case of different aryl substituents
in the 1,5-diarylpenta-1,4-dien-3-ones presumably two
structural isomers may form. Actually, as showed our
studies, the reaction of Reformatsky reagent I obtained
from methyl 1-bromocyclopentanecarboxylate and
zinc with 1-(4-methoxyphenyl)-5-phenylpenta-1,4-
dien-3-one (IIa) afforded 10-(4-methoxyphenyl)-8-(2-
phenylethenyl)-7-oxaspiro[4.5]dec-8-en-6-one (Va) in
22% yield and 8-[2-(4-methoxyphenyl)ethenyl]-10-phe-
nyl-7-oxaspiro[4.5]dec-8-en-6-one (VIa) in 26% yield
arising as a result of the 1,4-addition of the organozinc
compound to one of the C=C–C=O fragments of the di-
enone forming intermediates IIIa, IVa followed by their
cyclization with the liberation of zinc bromomethylate.
The composition and structure of compounds Va, VIa
were confirmed by the data of elemental analysis, IR,
1H NMR, and mass spectra. The structure of compound
Va was proved by XRD analysis.
Ar
O
OMe
Ar
_MeOZnBr
OZnBr
O
O
PhCH=CHC(O)CH=CHAr
ZnBr
Ph
Ph
Br
COOMe
IIa_IIc
Va_Vc
IIIa_IIIc
Zn
COOMe
Ph
O
I
OMe
OZnBr
Ph
_MeOZnBr
O
O
Ar
Ar
VIa_VIc
IVa_IVc
Ar = 4-MeOC6H4 (a), 4-ClC6H4 (b), 4-BrC6H4 (c).
1090

REACTION OF METHYL 1-BROMOCYCLOPENTANECARBOXYLATE
1091
According to XRD data the compound crystallizes in
a chiral space group of symmetry in a rhombic crystal
system. The general view of the molecule is given on
the figure. The structure is characterized by the S-trans-
configuration of the butadiene fragment and trans-
configuration of the ethylene fragment C7–C8. The bond
lengths and bond angles are close to the standard values.
The phenyl substituent as a whole lies in the plane of
the conjugated butadiene system. The dihydropyranone
ring is nonplanar and has a structure of a sheet folded
along the axis going through atoms C9–C12. The angle
between the least-mean-square planes C13C12O3C9 and
C9C10C11C12 equals 32.7 deg. The methoxyphenyl sub-
stituent is located in a pseudoaxial position. The atom
C15 of the cyclopentane ring is disordered in the position
2 with the population factors 0.5. The crystal packing
lacks any pronounced shortened contacts.
Geometry of compound Va according to XRD analysis pre-
sented in ellipsoids of 50% probablility.
The reaction of Reformatsky reagent I with dienones
IIb, IIc led to the formation of virtually individual reac-
tion products.According to the chromatography the con-
tent of the minor products in the separated mixtures was
6.2 and 1.5% respectively. Inasmuch as in the 1H NMR
spectra of compounds obtained the chemical shifts of the
proton signals of the ethenyl groups (6.49 and 7.12 ppm)
coincide with the chemical shifts of protons of this group
in compound Va (6.49 and 7.11 ppm) (proton signals of
the ethenyl group of compound VIa are observed at 6.37
and 7.07 ppm), a conclusion is logical that in all these
compound the phenyl substituent is attached to its group,
and the main reaction products are compound Vb, Vc.
ions [ArCH=CHCO]+ and [ArCH=CH]+, whereas in the
spectra of the minor isomers the intensity of the former
peaks sharply decreases and of the latter peaks signifi-
cantly grows. This means that the characteristic region of
spectra of the prevailing isomers is qualitatively similar
to the spectrum of compound Va, and the spectra of the
minor isomers resemble that of compound VIa. There-
fore in keeping with the mass spectral data the prevailing
isomers of the chloro- and bromo-substituted compounds
should be identified as structures Vb, Vc.
EXPERIMENTAL
The same conclusion follows from the analysis
of mass spectra. The mass spectra of compounds Va,
VIa contain the same peaks, but the pronounced dif-
ference in intensity exists for cations with the values
of m/z 161 [ArCH=CHCO]+, 133 [ArCH=CH]+, 131
[PhCH=CHCO]+, 103 [PhCH=CH]+. This difference
shows firstly that the fragmentation character is governed
mainly by the identical part of the isomers structure, Sec-
ondly, the triple increase (from 6/17 to 10/9) in the ratio
of the intensity of the signal of ion [ArCH=CH]+ to that
of the ion [PhCH=CH]+ in going from Va to VIa indicates
independently of XRD data that the first compound has
V structure, and the second one, VI structure, since it
is expectable to obtain the arylvinyl ion predominantly
from the substituent in the position 8. In the mass spectra
of the halosubstituted compounds the intensity of peaks
of ions [PhCH=CHCO]+ and [PhCH=CH]+ in the pre-
dominant isomers is higer than the intensity of peaks of
IR spectra were recorded on a spectrophotometer
Specord 75IR from mulls in mineral oil. 1H NMR spec-
tra were registered on a spectrometer Mercury Plus-300
(300 MHz) from solutions in CDCl3, internal reference
HMDS. Chromatograms and mass spectra were obtained
on a GC-MS instrument Agilent 6890N/5975B (column
HP-5ms, 30 m × 0.25 mm × 0.25 μm, carrier gas helium,
ionization by electron impact, 70 eV).
XRD analysis of compound Va was carried out on
an automatic four-circle diffractometer Xcalibur 3 with
a CCD-detector along a standard procedure [T 295(2) K,
MoKα-radiation, graphite monochromator, ω-scanning,
scanning step 1°]. No correction for extinction was
done (μ 0.080 mm–1). Crystal rhombic, space group
P212121, a 6.1724(4), b 17.0843(18), c 18.357(2) Å,
V 1935.8(3) Å3. C24H24O3. Z 4. Within scattering angles
2.63 < θ < 26.39° 11046 reflections were collected,
among them 2295 independent (Rint 0.0475), 1052 with
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 48 No. 8 2012

KIRILLOV et al.
1092
mp 182–184°C. IR spectrum, ν, cm–1: 1770 (C=O),
1655 (C=C). H NMR spectrum, δ, ppm: 1.08–2.13 m
I > 2σ(I), completeness 99.7%. The structure was solved
by the direct method and refined using program package
SHELXTL-97 [2] in the anisotropic (isotropic for hydro-
gen atoms) approximation. Some hydrogen atoms were
solved directly and refined independently, a part of hy-
drogen atoms was located in the geometrically calculated
positions and was included in refining in the rider model
with dependent thermal parameters. The final refinement
parameters: R1 0.0321, wR2 0.0508 [I > 2σ(I)], R1 0.0895,
wR2 0.0542 (with respect to all reflections) at quality fac-
tor 1.000. The peaks of maximum and minimum residual
electron density are 0.106 and –0.109 ēÅ–3.
1
[8H, (CH2)4], 3.34 d (1H, H10, J 6.6 Hz), 5.50 d (1H,
H9, J 6.6 Hz), 6.49 d, 7.12 d (2H, CH=CH, J 15.6 Hz),
7.05 d, 7.25 d (4H, 4-ClC6H4, J 8.4 Hz), 7.28 d [1H, Cп
(Ph), J 7.5 Hz], 7.34 t [2H, Cm (Ph), J 7.5 Hz], 7.44 d
[2H, Co (Ph), J 7.5 Hz]. Mass spectrum, m/z (Irel, %):
364 [M]+ (24), 269 [M – C5H7CO]+ (100), 268 [M –
– C5H8CO]+ (4), 267 [M – C5H9CO]+ (8), 165
[ClC6H4CH=CHCO]+ (5), 137 [ClC6H4CH=CH]+ (2),
131 [PhCH=CHCO]+ (36), 103 [PhCH=CH]+ (18), 96
[C5H8CO]+ (56), 77 [Ph]+ (12), 68 [C5H8]+ (22). Found,
%: C 75.82; H 5.92; Cl 9.60. C23H21ClO2. Calculated, %:
C 75.71; H 5.80; Cl 9.72.
The complete set of the crystallographic data of com-
pound Va is deposited in the Gambridge Crystallographic
Database (CCDC no. 893372) and is available at the
address www.ccdc.cam.ac.uk/conts/retrieving.html (or
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK; fax:
+44 1223 336033; e-mail: deposit@ccdc.cam.ac.uk).
10-(4-Bromophenyl)-8-(2-phenylethenyl)-7-
oxaspiro[4.5]dec-8-en-6-one (Vc). Yield 0.92 g (45%),
mp 204–206°C. IR spectrum, ν, cm–1: 1770 (C=O),
1
1655 (C=C). H NMR spectrum, δ, ppm: 1.10–2.12 m
[8H, (CH2)4], 3.33 d (1H, H10, J 6.6 Hz), 5.49 d (1H, H9,
J 6.6 Hz), 6.49 d, 7.12 d (2H, CH=CH, J 15.9 Hz), 6.99 d,
7.41 d (4H, 4-BrC6H4, J 8.4 Hz), 7.28 d, 7.34 t, 7.44 d (5H,
Ph, J 7.5 Hz). Mass spectrum, m/z (Irel, %): 408 [M]+ (17),
313 [M – C5H7CO]+ (83), 312 [M – C5H8CO]+ (3), 311
[M – C5H9CO]+ (7), 209 [BrC6H4CH=CHCO]+ (3), 181
[BrC6H4CH=CH]+ (3), 131 [PhCH=CHCO]+ (61), 103
[PhCH=CH]+ (36), 96 [C5H8CO] + (100), 77 [Ph]+ (26),
68 [C5H8] + (46). Found, %: C 67.61; H 5.11; Br 19.33.
C23H21BrO2. Calculated, %: C 67.49; H 5.17; Br 19.52.
Compounds Va–Vc, VIa. General procedure.
A mixture of 1.5 g of fine zinc turnings, a catalytic
quantity of mercury(II) chloride, 5 mmol of 1-aryl-
5-phenyl-penta-1,4-dien-3-one, 5.1 mmol of methyl
1-bromocyclopentanecarboxylate, 20 ml of benzene, 5 ml
of ethyl acetate, and 1 ml of HMPA was boiled for 2 h,
cooled, decanted from excess zinc, and was treated with
5% solution of hydrochloric acid. The organic layer was
separated, the water layer was twice extracted with ethyl
actate. The organic solutions were dried with anhydrous
sodium sulfate, the solvent was distilled off, the reaction
products were recrystallized from ethyl acetate.
8-[2-(4-Methoxyphenyl)ethenyl]-10-phenyl-7-
oxaspiro[4.5]dec-8-en-6-one (VIa). Yield 0.47 g (26%),
mp 123–124°C. IR spectrum, ν, cm–1: 1765 (C=O),
10-(4-Methoxyphenyl)-8-(2-phenylethenyl)-7-
oxaspiro[4.5]dec-8-en-6-one (Va). Yield 0.40 g (22%),
mp 164–165°C. IR spectrum, ν, cm–1: 1765 (C=O),
1
1665 (C=C). H NMR spectrum, δ, ppm: 1.32–2.12 m
[8H, (CH2)4], 3.35 d (1H, H10, J 6.3 Hz), 3.81 s (3H,
OMe), 5.48 d (1H, H9, J 6.3 Hz), 6.37 d, 7.07 d (2H,
CH=CH, J 15.9 Hz), 6.87 d, 7.38 d (4H, 4-MeOC6H4,
J 8.7 Hz), 7.22–7.32 m (5H, Ph). Mass spectrum, m/z
(Irel, %): 360 [M]+ (48), 265 [M – C5H7CO]+ (54), 264
[M – C5H8CO]+ (100), 263 [M – C5H9CO]+ (32), 161
[CH3OC6H4CH=CHCO]+ (40), 133 [CH3OC6H4CH=CH]+
(10), 131 [PhCH=CHCO]+ (5), 103 [PhCH=CH]+ (9),
96 [C5H8CO] + (4), 77 [Ph]+ (8), 68 [C5H8] + (6). Found,
%: C 79.82; H 6.84. C24H24O3. Calculated, %: C 79.97;
H 6.71.
1
1660 (C=C). H NMR spectrum, δ, ppm: 1.32–2.10 m
[8H, (CH2)4], 3.32 d (1H, H10, J 6.3 Hz), 3.77 s (3H,
OMe), 5.52 d (1H, H9, J 6.3 Hz), 6.49 d, 7.11 d (2H,
CH=CH, J 15.9 Hz), 6.81 d, 7.03 d (4H, 4-MeOC6H4,
J 8.7 Hz), 7.26 d, 7.33 t, 7.44 d (5H, Ph, J 7.8 Hz).
Mass spectrum, m/z (Irel, %): 360 [M]+ (39), 265 [M –
C5H7CO]+ (55), 264 [M – C5H8CO]+ (100), 263 [M –
C5H9CO]+ (32), 161 [CH3OC6H4CH=CHCO]+ (10), 133
[CH3OC6H4CH=CH]+ (6), 131 [PhCH=CHCO]+ (23),
103 [PhCH=CH]+ (17), 96 [C5H8CO]+ (4), 77 [Ph]+ (12),
68 [C5H8] + (7). Found, %: C 80.09; H 6.92. C24H24O3.
Calculated, %: C 79.97; H 6.71.
10-Phenyl-8-[2-(4-chlorophenyl)ethenyl]-7-
oxaspiro[4.5]dec-8-en-6-one (VIb). Mass spectrum,
m/z (Irel, %): 364 [M]+ (27), 269 [M – C5H7CO]+ (100),
268 [M – C5H8CO]+ (4), 267 [M – C5H9CO]+ (8), 165
8-(2-Phenylethenyl)-10-(4-chlorophenyl)-7-ox-
aspiro[4.5]dec-8-en-6-one (Vb). Yield 0.77 g (42%),
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 48 No. 8 2012

REACTION OF METHYL 1-BROMOCYCLOPENTANECARBOXYLATE
1093
[ClC6H4CH=CHCO]+ (28), 137 [ClC6H4CH=CH]+ (6),
ACKNOWLEDGMENTS
131 [PhCH=CHCO]+ (3), 103 [PhCH=CH]+ (8), 96
[C5H8CO] + (59), 77 [Ph]+ (7), 68 [C5H8] + (22).
The study was carried out under a financial support
of the Ministry of Education and Science of the Russian
Federation (project 1.12.11).
8-[2-(4-Bromophenyl)ethenyl]-10-phenyl-7-oxa-
spiro[4.5]dec-8-en-6-one (VIc). Mass spectrum, m/z
(Irel, %): 408 [M]+ (20), 313 [M – C5H7CO]+ (91),
312 [M – C5H8CO]+ (4), 311 [M – C5H9CO]+ (9), 209
[BrC6H4CH=CHCO]+ (21), 181 [BrC6H4CH=CH]+ (4),
131 [PhCH=CHCO]+ (17), 103 [PhCH=CH]+ (23), 96
[C5H8CO] + (100), 77 [Ph]+ (16), 68 [C5H8] + (43).
REFERENCES
1. Kirillov, N.F., Gavrilov,A.G., Vakhrin, M.I., and Feshin, V.P., Zh.
Org. Khim., 2011, vol. 81, p. 1002.
2. Sheldrick, G.M., Acta Cryst. 2008, vol. A64, p. 112.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 48 No. 8 2012