Synthesis and x-ray single crystal structure of dialkyl 2-[1-(2,2-dimethylpropionyl)-3,3-dimethyl-2-oxobutyl]-3- (triphenylphosphoranylidene)succinates

Article abstract of DOI:10.1515/znb-2006-0911

A one-pot synthesis of sterically congested phosphorus ylides in fairly high yields by the reaction of 2,2,6,6-tetramethyl-3,5-heptanedione, dialkyl acetylenedicarboxylates and triphenylphosphine is reported. The structures of these compounds were confirm

Full text of DOI:10.1515/znb-2006-0911

Synthesis and X-Ray Single Crystal Structure of Dialkyl
2-[1-(2,2-Dimethylpropionyl)-3,3-dimethyl-2-oxobutyl]-3-
(triphenylphosphoranylidene)succinates
a
a
a
b
´
Ali Ramazani , Ali Reza Kazemizadeh , Ebrahim Ahmadi , Katarzyna Slepokura , and
Tadeusz Lisb
a Department of Chemistry, the University of Zanjan, P O Box 45195-313, Zanjan, Iran
b Faculty of Chemistry, University of Wrocław, 14 Joliot-Curie St., 50-383 Wrocław, Poland
Reprint requests to Dr. A. Ramazani. Fax: +98 241 5283100. E-mail: aliramazani@yahoo.com
Z. Naturforsch. 61b, 1128 – 1133 (2006); received May 9, 2006
A one-pot synthesis of sterically congested phosphorus ylides in fairly high yields by the reaction
of 2,2,6,6-tetramethyl-3,5-heptanedione, dialkyl acetylenedicarboxylates and triphenylphosphine is
reported. The structures of these compounds were confirmed by IR, 1H, 31P and 13C NMR spec-
troscopy, and X-ray single crystal structure determination. The NMR spectra (CDCl3 as solvent)
indicated that the compounds contained two rotamers for each ylide.
Key words: 2,2,6,6-Tetramethyl-3,5-heptanedione, Phosphorus Ylide, Acetylenic Ester,
Vinyltriphenylphosphonium Salts
Introduction
bases can be used if the salt is acidic enough. In re-
cent years, we have established a one-pot method for
the synthesis of stabilized ylides [5 – 8]. In this paper,
we wish to describe the preparation of sterically con-
gested phosphorus ylides from the CH-acid 2,2,6,6-
tetramethyl-3,5-heptanedione in fairly high yields.
Phosphorus ylides are a class of special type of zwit-
terions, which bear strongly nucleophilic electron rich
carbanions. The electron distribution around the P+–
C− bond and its consequent chemical implications had
been probed and assessed through theoretical, spectro-
scopic and crystallographicinvestigations [1]. They are
excellent ligands and excel in their ligating functions
the unstabilized ylides because of their ambidentate
and chemically differentiating character. Proton affin-
ity of these ylides can be used as a molecular guide
to assess their utility as synthetic reagents and their
function as ligands in coordination and organometal-
lic chemistry [2]. The nucleophilicity at the ylidic car-
bon is a factor of essential mechanistic importance in
the use of these ylides as Wittig reagents. Phospho-
rus ylides are important reagents in synthetic organic
chemistry, especially in the synthesis of naturally oc-
curring products, compounds with biological and phar-
macological activity [3]. These ylides are usually pre-
pared by treatment of a phosphonium salt with a base,
and phosphonium salts are usually obtained from a
phosphane and an alkyl halide. Phosphonium salts are
Results and Discussion
The ylide 5 may result from initial addition of triph-
enylphosphane (1) to the acetylenic ester 2 and con-
comitant protonation of the 1 : 1 adduct, followed by
attack of the CH-acid anion on the vinyltriphenylphos-
phonium cation to form the stabilized phosphorane 5
(Scheme 1). The NMR spectra indicated that solutions
of compound 5 (CDCl3 as solvent) contain two ro-
tamers (5E and 5Z). The relative percentages of ro-
tamers in CDCl3 for each ylide 5 were determined
1
from the H NMR spectra. The structures 5a, b were
1
deduced from their H, 13C and 31P NMR spectra.
Description of the crystal structure of 5a
The crystal of 5a is built up from ylide molecules
also prepared by Michael addition of phosphorus nu- (Fig. 1) and disordered solvent molecules of differ-
cleophiles to activated olefins and in other ways [4]. ent type (see Experimental Section). In the investigated
The phosphonium salts are most often converted to the crystal, the chiral atom C(22) (Fig. 1, Table 1) had the
ylide by treatment with a strong base, though weaker S configuration.
c
0932–0776 / 06 / 0900–1128 $ 06.00 ꢀ 2006 Verlag der Zeitschrift fu¨r Naturforschung, Tu¨bingen · http://znaturforsch.com
- 10.1515/znb-2006-0911
Downloaded from De Gruyter Online at 09/12/2016 04:53:40AM
via free access

A. Ramazani et al. · 2,2,6,6-Tetramethyl-3,5-heptanedione
1129
Scheme 1. M = major rotamer and m = mi-
nor rotamer.
close to sp2 hybridization), which is reflected in the
distance of the P atom from the C(19)/C(20)/C(22)
˚
plane (0.36 A) and in the sum of the angles about
C(19) close to 360◦ (358.5(2)◦ with the mean value of
120◦). Such small degree of the pyramidalization of
the ylidic C atom in the stabilized ylide is accompanied
by other structural features; namely, shortening of the
Cylide–Cα [C(19)–C(20)] distance and the lengthening
of the C=O [C(20)=O(1)] distance (see Table 2 and
compare with the unaffected C(22)–C(23) distance
and the whole (C(23)=O(3))–O4–C24 ester group).
The partial double bond character of C(19)–C(20)
results in some increase of the rotational barrier around
it. Consequently, the two rotamers (5E and 5Z in
Scheme 1, with different O(1) to P orientation) may
be expected and were shown indeed by NMR to ex-
ist in equilibrium in CDCl3 solution. However, the
X-ray data demonstrated that, in the solid state, this
orientation may be opposite even in compounds of
highly related structures [9, 10]. The ylide molecules
in 5a and in the crystal of analogous compound de-
scribed recently (ethyl ester of a phenyl derivative
[9]) adopt different orientation of the carbonyl O(1)
atom with respect to the P atom. In 5a, the O(1) is
in syn, and in the related compound – in anti orienta-
tion. This is reflected in the values of the torsion angle
P–C(19)–C(20)–O(1), which is −16.0(2)◦ in 5a and
165.0(2)◦ in related compounds [9, 10]. However, all
that shows that the ester groups are slightly twisted out
of the plane of the ylidic atom C(19), reducing delocal-
ization to some extent. It is to note here, that a search of
the Cambridge Structural Database [10] revealed about
60 hits of stabilized ylides of related structures, with
Fig. 1. The molecular structure of the ylide 5a showing the
atom-numbering scheme. Displacement ellipsoids are drawn
at the 30% probability level.
The molecular geometry observed in 5a cor-
responds well with the knowledge on stabilized
phosphonium ylides [1, 9]. The values of P–C(19)
˚
˚
(1.731(2) A), C(19)–C(20) (1.421(2) A) and
˚
C(20)=O(1) (1.241(2) A) bond lengths are in
agreement with the previously observed ones and are
consistent with electronic delocalization involving the
P–C–(C=O) system. That leads to a nearly planar,
trigonal environment of the ylidic atom C(19) (it is
- 10.1515/znb-2006-0911
Downloaded from De Gruyter Online at 09/12/2016 04:53:40AM
via free access

1130
A. Ramazani et al. · 2,2,6,6-Tetramethyl-3,5-heptanedione
˚
Table 1. Crystal data and structure refinement details for 5a.
Table 2. Selected interatomic distances [A], valence angles
[◦] and torsion angles [◦] in 5a.
Crystal data
Empirical formula
C35 H41 O6 P
588.65
P-C(1)
P-C(7)
P-C(13)
P-C(19)
O(1)-C(20)
O(2)-C(20)
O(2)-C(21)
O(3)-C(23)
1.813(2) O(4)-C(23)
1.806(2) O(4)-C(24)
1.821(2) O(5)-C(26)
1.731(2) O(6)-C(31)
1.241(2) C(19)-C(20)
1.369(2) C(19)-C(22)
1.433(2) C(22)-C(23)
1.210(2)
1.345(2)
1.442(2)
1.221(2)
1.215(2)
1.421(2)
1.519(2)
1.527(2)
Formula weight (g mol−1
)
Crystal system, space group
Unit cell dimensions [A]
orthorhombic, P212121
a = 10.401(2)
b = 14.433(3)
c = 27.400(4)
4113.2(13)
4
0.951
0.863
1256
˚
3
˚
V [A ]
Z
Dcalc [g cm−3
]
C(1)-P-C(7)
105.96(7) C(20)-O(2)-C(21)
112.76(7) C(23)-O(4)-C(24)
104.10(7) C(20)-C(19)-P
106.29(7) C(22)-C(19)-P
109.60(7) C(20)-C(19)-C(22) 120.52(13)
117.34(7)
115.26(13)
115.06(12)
114.60(11)
123.41(11)
µ [mm−1
F(000)
]
C(1)-P-C(19)
C(1)-P-C(13)
C(7)-P-C(13)
C(7)-P-C(19)
C(13)-P-C(19)
Crystal size [mm]
Crystal color and form
0.40×0.25×0.25
Colorless needle
Data collection
Diffractometer
Monochromator
Xcalibur PX
Graphite
Cu-Kα , 1.5418
100(2)
4.45 – 76.12
−12 ≤ h ≤ 12,
−11 ≤ k ≤ 18,
−32 ≤ l ≤ 29
analytical
0.747/0.869
36083
8035 [Rint = 0.0327]
7582
P-C(19)-C(20)-O(1) −16.0(2) C(7)-P-C(19)-C(22)
C(7)-P-C(19)-C(20) −160.7(2) C(1)-P-C(19)-C(22)
5.6(2)
123.3(2)
˚
Radiation type, wavelength, λ [A]
C(1)-P-C(19)-C(20)
C(13)-P-C(19)-C(20)
−42.9(2) C(13)-P-C(19)-C(22) −115.7(2)
T [K]
78.1(2)
θ Range [◦]
h, k, l Ranges
eclipsed or parallel [1], which means that one of the
C(19) substituents (atom C(22)) is in synperiplanar
conformation with respect to one of the P-bonded
phenyl substituents (atom C(7)); the torsion angle
C(7)–P–C(19)–C(22) is 5.6(2)◦. On the other hand,
the analysis of the ylide P–C distances and the
Absorption correction
Tmin/Tmax
Measured reflections
Independent reflections
Observed refl. (I > 2σ(I))
Completeness to θ = 70.00◦
˚
C–P–C(19) angle reveals that P–C(13) (1.821(2) A)
0.997
and C(13)–P–C(19) (117.34(7)◦) are larger than the
other values, which could make the C(13) phenyl
group the so-called unique substituent, which, in com-
bination with the torsion angle C(13)–P–C(19)–C(20)
(78.1(2)◦) could imply the so-called planar or perpen-
dicular [1] conformation around the P–C(19) bond.
Nevertheless, with the additional lack of the character-
istic bend of the ylide substituents at the ylidic carbon
C(19) [C(20), C(22)] toward the C(13) phenyl group,
the eclipsed conformation gives a better description of
the conformation around the P–C(19) bond.
Refinement
Refinement on
Data/restraints/parameters
R(Fo2 > 2σ(Fo2))
R (all data)
F2
8035/0/389
R1 = 0.0366, wR2 = 0.1020
R1 = 0.0379, wR2 = 0.1031
1.097
0.0792/0.0
0.33/-0.28
GooF = S
Weighting paramet−er3 a/b
˚
∆ρmax/∆ρmin [e A
]
Flack parameter
0.045(14)
ꢀ
R1 = ΣꢀFo|−|Fcꢀ/Σ|Fo|; wR2 = Σ[w(Fo −Fc2)2]/Σ[w(Fo2)2].
2
Weighting scheme: w = 1/[σ2(Fo2)+(aP)2 +bP] where P = (F
+
2
o
2F 2)/3.
c
most of them existing in anti rather than syn copla-
nar conformation. Most of them also showed the ester
group slightly twisted.
The geometry at the phosphorus atom reveals a de-
formed tetrahedral shape with the largest deformations
observed for the bond distance P–C(19) and the bond
Both ester moieties in 5a, (C(20)=O(1))–O(2)– angle C(13)–P–C(19) (Table 2), which is a common
C(21) and (C(23)=O(3))–O(4)–C(24) are almost pla-
nar with the methyl C(21) and C(24) atoms being
nearly coplanar with the rest. The distances of atoms
C(21) or C(24) from the planes C(20)/O(1)/O(2) and
feature of compounds with related structure.
The molecular structure of 5a is stabilized by intra-
and intermolecular C–H···O interactions (Fig. 2), the
geometry of which is given in Table 3. Additionally,
the syn orientation of O(1) atom to P atom favors short
intramolecular P···O contacts with a P···O(1) dis-
˚
C(23)/O(3)/O(4) are about 0.03 and 0.04 A, respec-
tively. This is also reflected in the torsion angle
C(21)–O(2)–C(20)–O(1) and C(24)–O(4)–C(23)–O(3)
of 1.5(2) and 1.9(2)◦, respectively.
˚
tance of 2.961(2) A. Every phenyl ring is involved in
one intramolecular C–H···O interaction and additional
The mutual orientation around the ylidic atoms intermolecular contacts of the same type. The adja-
P and C(19) atoms in 5a may be described as cent molecules are joined to each other to form two-
- 10.1515/znb-2006-0911
Downloaded from De Gruyter Online at 09/12/2016 04:53:40AM
via free access

A. Ramazani et al. · 2,2,6,6-Tetramethyl-3,5-heptanedione
1131
Fig. 2. The arrangement of the ylide molecules in the crystal 5a. Dashed lines show intra- and intermolecular C–H···O close
contacts. Symmetry codes are given in Table 3.
Table 3. Geometry of proposed C–H···O close contacts for
and long C=O distance, and coplanar P–Cylide–Cα –
Ocarbonyl conformation, which all indicate the effective
electronic delocalization.
◦
˚
5a (A, ).
D-H···A
D-H
H···A
D···A
D-H···A
(◦)
˚
˚
˚
(A)
(A)
(A)
C(3)-H(3)···O(5)i
C(5)-H(5)···O(6)ii
C(6)-H(6)···O(4)
C(9)-H(9)···O(1)iii
C(12)-H(12)···O(6)
C(14)-H(14)···O(1)
C(16)-H(16)···O(6)iv
C(17)-H(17)···O(5)iv
C(29)-H(29C)···O(3)v
C(34)-H(34A)···O(2)
i
0.95
0.95
0.95
0.95
0.95
0.95
0.95
0.95
0.98
0.98
2.65
2.54
2.55
2.30
2.40
2.35
2.46
2.50
2.64
2.64
3.475(2)
3.477(2)
3.418(2)
3.145(2)
3.279(2)
3.161(2)
3.395(2)
3.272(2)
3.581(2)
3.474(2)
146
170
153
147
153
143
170
138
160
143
Experimental Section
Melting points were measured on an Electrothermal 9100
apparatus and are uncorrected. Elemental analyses were per-
formed using a Heraeus CHN-O-Rapid analyzer. IR spectra
were recorded on a Shimadzu IR-460 spectrometer. 1H, 13
C
and 31P NMR spectra were measured with a BRUKER DRX-
500 AVANCE spectrometer at 500, 125 and 202.44 MHz,
respectively. 5a was analyzed with CD (spectropolarimeter
Jasco J-600) and GC/MS (EI) (Hewlett Packard gas chro-
matograph HP 5890II with mass detector HP 5971A).
ii
iii
Symmetry codes: −x,y + 1/2,−z + 1/2; x − 1,y,z;
−x,y −
iv
v
1/2,−z + 1/2;
1/2,−z+1.
−x + 1,y + 1/2,−z + 1/2;
x + 1/2,−y +
dimensional, folded molecular layers parallel to the
(001) plane. The channels formed between the layers
are occupied by highly disordered solvent molecules
(see Experimental Section).
Preparation of 2-[1-(2,2-dimethylpropionyl)-3,3-dimethyl-2-
oxobutyl]-3-(triphenylphosphoranylidene)succinic acid
dimethyl ester (5a)
G e n e r a l p r o c e d u r e
Concluding remarks
To a magnetically stirred solution of triphenylphosphane
(0.066 g, 0.25 mmol) and 2,2,6,6-tetramethyl-3,5-heptane-
dione (0.05 ml, 0.25 mmol) in dichloromethane (5 ml)
was added dropwise a mixture of dimethyl acetylenedicarb-
oxylate (0.03 ml, 0.25 mmol) in dichloromethane (2 ml)
at −10 ◦C over 15 min. The mixture was allowed to
warm up to r. t. The mixture was cloudy white, and it
was filtered, the filtrate being evaporated to dryness as a
In conclusion, we have developed a convenient, one-
pot method for preparing stabilized ylides (5a – b) util-
ising in situ generation of the phosphoniumsalts. Other
aspects of this process are under investigation. The
X-ray structure of 5a revealed a number of common
features of stabilized ylides: deformed tetrahedral P
centre, near planar ylide carbon atom, short Cylide–Cα white solid. Then colorless crystals were obtained from
- 10.1515/znb-2006-0911
Downloaded from De Gruyter Online at 09/12/2016 04:53:40AM
via free access

1132
A. Ramazani et al. · 2,2,6,6-Tetramethyl-3,5-heptanedione
dichloromethane/petroleum ether (20 – 25 ◦C). Yield: 0.14 g Cryosystems cooler. A summary of the conditions for the
(95%); m. p. 187.0 – 188.7 ◦C. – IR (KBr): ν = 1726, 1626, data collection and the structure refinement parameters are
1
1441 cm−1. – H NMR (CDCl3, major rotamer (M) 50.4% given in Table 1. The data were corrected for Lorentz and
and minor rotamer (m) 49.6%): δ = 1.06, 1.14, 1.22 and 1.24 polarization effects. Analytical absorption correction was ap-
(4s, 18 H, CH3), 3.13, 3.53 and 3.59 (3s, 6H, OCH3), 3.74 – plied. Data collection, cell refinement, and data reduction
3
3.80 (m, 1 H, CHCO2Me), 5.90 (1H, d, JHH = 10.36 Hz) and analysis were carried out with the Xcalibur PX software
and 6.13 (1H, d, 3JHH = 9.85 Hz, CH(COtBu)2); 7.47 – 7.68 (Oxford Diffraction Poland): CrysAlis CCD and CrysAlis
(3m, 15H, Harom). – 13C NMR (CDCl3): δ = 27.41, 27.50, RED, respectively [11]. The structure was solved by direct
27.97 and 28.12 (4 C(CH3)3); 40.73 (d, 1JPC = 121.63 Hz) methods using the SHELXS-97 program [12] and refined
1
and 42.02 (d, JPC = 128.58 Hz) (2 P=C); 45.09, 45.28, by a full-matrix least-squares technique using SHELXL-97
45.77 and 45.94 (4C(CH3)3); 49.41 (d, 2JPC = 13.04 Hz) and [13] with anisotropic thermal parameters for non-H atoms of
2
49.90 (d, JPC = 13.10 Hz) (2P=C-C); 48.70, 49.90, 51.29 the 5a molecule. All H atoms were placed in calculated po-
3
and 51.37 (4 OCH3); 55.94 (d, JPC = 2.77 Hz) and 56.69 sitions and were treated as riding atoms, with C–H distances
(d, 3JPC = 5.98 Hz) (2CH(COtBu)2); 128.26 – 135.42 (fairly of 0.95 – 1.00 A, and with Uiso(H) values of 1.5 Ueq(C) for
˚
2
complex, Carom); 169.55 (d, JPC = 14.21 Hz), 171.10 (d, methyl or 1.2 Ueq(C) for aromatic and CH groups. All figures
2JPC = 19.75 Hz), 175.21 (d, 3JPC = 3.20 Hz) and 175.47 (d, were made using XP program [14]. The absolute configura-
3JPC = 4.02 Hz) (4 CO of esters); 210.00, 210.05, 210.15 and tion was determined by the anomalous dispersion effect [15].
210.54 (4 CO of ketones ). – 31P NMR (CDCl3): δ = 23.80, The extinction was also refined with the final extinction co-
24.51. – C35H41O6P (588.26): calcd. C 71.41, H 7.02; found efficient of 0.0034(3).
C 69.73, H 7.98.
After the diffraction experiment, the crystal was dissolved
in dichloromethane. The optical rotation was not possible to
be measured, due to low concentration of the solution (2.17·
10−4 M). Nevertheless, the CD spectrum could be recorded.
In the crystal of 5a, channels along the a axis are present,
in which the molecules of the crystallization solvent are
located. Since the compound has been recrystallized from
dichloromethane/petroleum ether, the voids in the crystals
are filled up with the molecules of different type, and of dif-
ferent occupation factors. The GC/MS analysis of the crystal
revealed presence of at least five different compounds in the
crystal of 5a, with the most intense chromatographic peak
ascribed to n-hexane.
To eliminate the possibility that the disorder in the solvent
region was due to the immediate chilling of the crystal (by
direct putting it in the gas stream of 100 K), the next diffrac-
tion experiment was performed (the results of which are pre-
sented here), in which the crystal was put in the gas stream of
r. t. and then the temperature was slowly decreased (with the
rate of 120 K/h). However, this procedure did not prevent the
disorder in the crystal. The molecules of the solvent used in
the synthesis and crystallization were highly disordered and
could not be recognized in the disordered electron density.
Therefore, the contribution of the solvent to the diffraction
pattern was incorporated in the model using the SQUEEZE
option in PLATON [16]. Disordered solvent is present in two
Selected data for 2-[1-(2,2-dimethylpropionyl)-3,3-dimethyl-
2-oxobutyl]-3-(triphenylphosphoranylidene)succinic acid
diethyl ester 5b
Col◦orless crystals. – Yield: 0.14 g (91%); m. p. 169.0 –
171.0 C. – IR (KBr): ν = 1726, 1626, 1487, 1441 cm−1
.
–
1H NMR (CDCl3, major rotamer (M) 57.4% and minor
rotamer (m) 42.6%): δ = 1.05, 1.14, 1.23 and 1.24 (4s, 18
H, CH3); 0.54, 1.12, 1.17 and 1.27 (4t, 6H, 3JHH = 7.1 Hz,
OCH2CH3); 3.53 – 3.60 (m, 1 H, CHCO2Et); 3.70 – 3.86,
3.92 – 4.04 and 4.08 – 4.11 (3m, 4 H, OCH2); 5.91 (d, 1
3
3
H, JHH = 10.4 Hz) and 6.13 (d, 1 H, JHH = 10.1 Hz)
(CH(COtBu)2); 7.45 – 7.71 (3m, 15 H, Harom). – 13C NMR
(CDCl3): δ = 14.17, 14.19, 14.22 and 15.01 (4 OCH2CH3);
27.38, 27.44, 28.02 and 28.20 (4 C(CH3)3); 40.26 (d, 1JPC
=
1
121.31 Hz) and 41.86 (d, JPC = 129.13 Hz) (2 P=C);
45.04, 45.30, 45.81 and 46.00 (4 C(CH3)3); 50.08 (d, 2JPC
=
13.05 Hz) and 50.59 (d, 2JPC = 13.14 Hz) (2P=C-C); 57.37,
3
58.16, 60.49 and 60.52 (4 OCH2CH3); 56.02 (d, JPC
5.66 Hz) and 56.66 (d, JPC = 5.03 Hz) (2 CH(COtBu)2);
128.16 – 134.32 (fairly complex, Carom); 169.17 (d, JPC
14.46 Hz), 170.86 (d, 2JPC = 19.75 Hz), 174.76 (d, 3JPC
3.65 Hz) and 175.09 (d, JPC = 4.02 Hz) (4 CO of es-
ters); 210.09, 210.15, 210.20 and 210.74 (4 CO of ke-
tones). – 31P NMR (CDCl3): δ = 23.58, 24.30. – C37H45O6P
(616.30): calcd. C 72.06, H 7.35; found C 69.73, H 7.98.
=
3
2
=
=
3
channels per unit cell, each located on a 21 axis. A total of
3
˚
89 electrons were found in every channel of about 614 A
each [located at (x, 1/4, 0) and (x, 3/4, 1/2)].
Crystal structure determination of 5a
The crystallographic measurement was performed on a
Xcalibur PX automated four-circle diffractometer with the
graphite-monochromatized Cu-Kα radiation. The data for
Supplementary material
Crystallographic data for the structure have been de-
the crystal were collected at 100(2) K using the Oxford posited with the Cambridge Crystallographic Data Centre,
- 10.1515/znb-2006-0911
Downloaded from De Gruyter Online at 09/12/2016 04:53:40AM
via free access

A. Ramazani et al. · 2,2,6,6-Tetramethyl-3,5-heptanedione
1133
CCDC-606706 and 606707 (with or without SQUEEZE pro- Acknowledgements
cedure). Copies of the data can be obtained free of charge on
The Iranian authors are thankful to the “Sandoogh
Hemayate as Pajuoheshgharane Keshvare Iran” for par-
tial support of this work via the research project number
N 84114.
application to The Director, CCDC, 12 Union Road, Cam-
bridge CB2 1EZ, UK (Fax: int.code+(1223)336 – 033; e-mail
for inquiry: fileserv@ccdc.cam.ac.uk).
[10] Cambridge Structural Database (CSD, Version 5.27 of
November 2005); F. H. Allen, Acta Cryst. B58, 380
(2002).
[11] Xcalibur PX software: CrysAlis CCD and CrysAlis
RED, Version 1.171, Oxford Diffraction Poland
(1995 – 2003).
[12] G. M. Sheldrick, SHELXS-97, Program for the solu-
tion of crystal structures, University of Go¨ttingen, Ger-
many (1997).
[13] G. M. Sheldrick, SHELXL-97, Program for the refine-
ment of crystal structures, University of Go¨ttingen,
Germany (1997).
[14] XP – Interactive molecular graphics, Version 5.1,
Bruker Analytical X-ray Systems (1998).
[15] H. D. Flack, Acta Cryst. A39, 876 (1983).
[16] A. L. Spek, PLATON – A Multipurpose Crystal-
lographic Tool, Utrecht University, Utrecht, The
Netherlands (2003); A. L. Spek, Acta Cryst. A46, C34
(1990).
[1] W. Johnson, Ylid Chemistry, Academic Press, New
York (1966); O. I. Kolodiazhnyi, Phosphorus Ylides:
Chemistry and Applications in Organic Chemistry, Wi-
ley, New York (1999); D. G. Gilheany, Chem. Rev. 94,
1339 (1994); S. M. Bachrach 57, 4367 (1992).
[2] W. C. Kaska, Coord. Chem. Rev. 48, 1 (1983).
[3] B. E. Maryanoff, A. B. Reitz, Chem. Rev. 89, 863
(1989).
[4] D. E. C. Cobridge, Phosphorus: An Outline of Chem-
istry, Biochemistry and Uses, 5th ed.; Elsevier, Amster-
dam (1995).
[5] I. Yavari, A. Ramazani, Synth. Commun. 26, 4495
(1996).
[6] I. Yavari, A. Ramazani, Phosphorus, Sulphur, and Sili-
con 130, 73 (1997).
[7] A. Ramazani, A. Bodaghi, Tetrahedron Lett. 41, 567
(2000).
[8] A. Ramazani, H. Ahani, Phosphorus, Sulphur, and Sili-
con 170, 181 (2001).
[9] A. Ramazani, L. Dolatyari, A. R. Kazemizadeh, E. Ah-
madi, A. A. Torabi, R. Welter, Z. Kristallogr. NCS 219,
181 (2004).
- 10.1515/znb-2006-0911
Downloaded from De Gruyter Online at 09/12/2016 04:53:40AM
via free access