Reaction of phosphorus pentachloride with 2,6-dichloro-4-phenylbenzo[e][1, 2λ5]oxaphosphinine 2-oxide. Synthesis and steric structure of 2,2,6-trichloro-4-phenylbenzo[e][1,2λ5]oxaphosphinin-2-ylium hexachlorophosphate

Article abstract of DOI:10.1134/s1070363208020060

2,2,2,6-Tetrachloro-4-phenylbenzo[e][1,2]oxaphosphinine and 2,2,6-trichloro-4-phenylbenzo[e][1,2λ⁵]-oxaphosphinin-2-ylium hexachlorophosphate were prepared by treatment of 2,6-dichloro-4-phenylbenzo[e] [1,2λ⁵]-oxaphosphinine 2-oxide

Full text of DOI:10.1134/s1070363208020060

ISSN 1070-3632, Russian Journal of General Chemistry, 2008, Vol. 78, No. 2, pp. 192 196.
Pleiades Publishing, Ltd., 2008.
Original Russian Text V.F. Mironov, E.N. Varaksina, D.A. Tatarinov, A.A. Shtyrlina, A.B. Dobrynin, I.A. Litvinov, 2008, published in Zhurnal Obshchei
Khimii, 2008, Vol. 78, No. 2, pp. 210 215.
Reaction of Phosphorus Pentachloride with 2,6-Dichloro-
5
4-phenylbenzo[e][1,2 ]oxaphosphinine 2-Oxide.
Synthesis and Steric Structure of 2,2,6-Trichloro-
5
4-phenylbenzo[e][1,2 ]oxaphosphinin-2-ylium
hexachlorophosphate
V. F. Mironov, E. N. Varaksina, D. A. Tatarinov,
A. A. Shtyrlina, A. B. Dobrynin, and I. A. Litvinov
Arbuzov Institute of Organic and Physical Chemistry, Kazan Research Center,
Russian Academy of Sciences, ul. Arbuzova 8, Kazan, 420088 Russia
Received June 29, 2007
Abstract 2,2,2,6-Tetrachloro-4-phenylbenzo[e][1,2]oxaphosphinine and 2,2,6-trichloro-4-phenylbenzo[e]-
[1,2 5]-oxaphosphinin-2-ylium hexachlorophosphate were prepared by treatment of 2,6-dichloro-4-phenyl-
benzo[e][1,2 5]-oxaphosphinine 2-oxide with phosphorus pentachloride. The structure of the latter compound
was proved by means of X-ray diffraction analysis.
DOI: 10.1134/S1070363208020060
Development of mild selective methods for con-
version of the phosphoryl group into a reactive penta-
coordinate phosphorus fragment opens up wide per-
spectives for synthesis of polysubstituted functionalized
organophosphorus compounds. Since the P=O group
is thermodynamically very stable, there has been little
work on its functionalizaton. Here we can mention
reduction with lithium aluminum hydride, silicochlo-
roform, and hydroiodic acid as an extensively used
synthetic approach to P(III) derivatives. Another
known process involving the phosphoryl group is the
reaction with strong halogenating reagents, such as
sulfur and antimony fluorides and phosphorus penta-
chloride [1, 2], leading to dihalophosphoranes. The
use of phosphorus pentachloride allows selective
substitution of one or two hydroxy or alkoxy groups
in phosphorous acids or esters with preservation of the
coordination number of phosphorus. Subsequent
chlorination of the phosphoryl group with phosphorus
pentachloride to increase the coordination number of
phosphorus is also possible [2]. However, these works
dealt mostly with acyclic P(IV) derivatives, whereas
cyclic derivatives of phosphonic and phosphinic acids
of a similar type were not involved in these reac-
tions.
chloro-4-phenylbenzo[e][1,2 5]-oxaphosphinine
2-oxide (I) synthesized earlier through the reaction of
2,2,2-trichloro-1,3,2-benzodioxaphosphole (II) with
phenylacetylene in methylene chloride. Oxide I is
a phosphorous analog of a widespread natural hetero-
cycle coumarin [3]. In our work we slightly changed
the method of synthesis of compound I and effected
the reaction in boiling dichloroethane. This allowed us
to exclude excess phenylacetylene and thus facilitate
separation of the product from chlorostyrene formed
by the side addition of HCl to phenylacetylene. Com-
pound I was prepared also via chlorination of 6-chloro-
5
2-hydroxy-4-phenylbenzo[e][1,2 ]oxaphosphosinine
2-oxide (III) with phosphorus pentachloride at a 1:1
starting reagent ratio. The structure of benzo-
phosphinine I and our previous data [4, 5] point to an
aromatic character of the oxaphosphinine fragment.
Therefore, changing the phosphorus coordination from
tetrahedral to trigonal-bipyramidal should affect sig-
nificantly the properties of both the heterocyclic sys-
tem and the phosphorus atom included into this hete-
rocycle. We found that the reaction of phosphinine I
with phosphorus pentachloride occurs in two steps
differing in their rates, that allowed us to obtain
intermediate phosphorane IV in 92 95% yield. The
reaction also gave POCl3 ( 2.0 ppm).
P
In the present work we for first time accomplished
reaction of phosphorus pentachloride with 2,6-di-
The phosphorus chemical shift of compound IV is
192

REACTION OF PHOSPHORUS PENTACHLORIDE
O
193
PCl3
O
II
ClCH2CH2Cl PhC CH
Cl
O
Cl
Cl
Cl
O
OH
O
O
O
P
P
P
, PCl5, C6H6
PCl5
Cl
OPCl3 Cl
Cl
O=PCl3
HCl
Ph
Ph
Ph
III
I
IV
+
P
Cl
O
PCl6
Cl
PCl5
PCl5
IV
Cl
Ph
V
1
characteristic of pentacoordinate phosphorus deri-
vatives ( 33.3 ppm, CH2Cl2) and consistent with
those reported for trichlorophosphoranes ( 25 to
36 ppm) [6]. Compound IV is relatively stable, but
with excess phosphorus pentachloride its phosphorus
downfield compared to compound I and their JHC
contants are considerably larger. The multiplicities of
all other carbon signals are analogous to those in the
spectrum of phosphinine I, providing evidence for the
absence of other conversions of the benzophosphinine
structure.
P
P
signal shifts downfield from
20 ppm to 29.2 ppm
and gets broader. In the protPon-coupled spectra, this
signal converts into a broadened doublet whose coupl-
The structure of salt V was also confirmed by
X-ray diffraction analysis of a crystal obtained by
crystallization from methylene chloride as a stable
solvate. Figure 1 depicts the geometry of this solvate
in the crystal. The phosphinine heterocycle has a
distorted boat conformation with two planar, within
0.010(3) , four-atomic fragments O1C8aC4aC4 and
2
ing constant JPCH varies in the range 39.1 44.6 Hz,
depending on solvent (methylene chloride or benzene)
and excess of phosphorus pentachloride. Thus the
2JPCH in benzene is 44.6 Hz. At a 1 mol excess of
phosphorus pentachloride, two signals appear in the
{1H}
31P
NMR spectrum (
63.8 ppm and
P2
con-
296.2 ppm), and, therewith,P1the singlet at
P1
2
verts into a broadened doublet with JPCH 28.3
Cl4
Cl9
Cl6
29.0 Hz in the 31P NMR spectrum. The
value is
also affected by the excess of phosphorus Pp1entachlo-
ride and can achieve 44.3 ppm (C6H6, excess of PCl5
Cl7
Cl8
Cl3
C6
110 120%). It is obvious that the signals at
and
P1
belong to phosphonium salt V, the first belonging
P2
Cl5
C11
to the phosphonium cation and the second, to the
hexachlorophosphate anion. Thus, phosphorus penta-
chloride was found to be a stronger Lewis acid com-
pared to phosphorane IV and, therefore, it is capable
of abstracting the chloride anion. It is interesting that
the 31P NMR spectrum of a solution of salt V in
methylene chloride shows signals of phosphorane IV
and phosphorus pentachloride together with the
C7
C10
C9
C12
C13
C8
C8a
C4
C4a
C3
C14
P2
O1
Cl1
Cl10
C20
Cl2
signals at
and
.
P1
P2
Cl
The structure of compounds IV and V was ad-
ditionally proved by 13C NMR spectroscopy. Note
that the C3 signals of compounds IV and V are shifted
Fig. 1. Geometry of the methylene chloride solvate in
the crystal of V.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 2 2008

194
MIRONOV et al.
Principal bond lengths (d, ) and bond ( , deg) and torsion angles ( , deg) in the methylene chloride solvate of V
Bond
Cl1 P2
d
Bond
d
Bond
d
1.956(1)
1.935(1)
1.741(3)
2.151(1)
2.148(1)
2.114(1)
2.150(1)
2.1368(9)
2.124(1)
P2 C3
1.731(3)
1.554(2)
1.420(4)
1.363(5)
1.470(5)
1.493(4)
1.405(5)
1.404(4)
1.377(5)
C6 C7
1.388(4)
1.386(5)
1.360(5)
1.392(5)
1.389(5)
1.397(4)
1.372(5)
1.380(5)
1.393(4)
Cl2 P2
Cl3 C6
Cl4 P1
Cl5 P1
Cl6 P1
Cl7 P1
Cl8 P1
Cl9 P1
P2 O1
C7 C8
O1 C8A
C3 C4
C8 C8A
C9 C10
C9 C14
C10 C11
C11 C12
C12 C13
C13 C14
C4 C4A
C4 C9
C4A C5
C4A C8A
C5 C6
Angle
Angle
Angle
Cl1P2Cl2
Cl1P2O1
Cl1P2C3
Cl2P2O1
Cl2P2C3
O1P2C3
106.90(5)
108.53(8)
111.9(1)
105.71(9)
116.0(1)
107.5(1)
89.55(4)
89.92(5)
90.49(4)
89.49(4)
Cl5P1Cl8
Cl5P1Cl9
Cl6P1Cl7
Cl6P1Cl8
Cl6P1Cl9
Cl7P1Cl8
Cl7P1Cl9
Cl8P1Cl9
Cl4P1Cl5
Cl4P1Cl6
90.08(5)
90.24(5)
90.24(4)
179.41(6)
90.39(4)
89.91(4)
179.32(5)
89.46(4)
179.59(4)
89.88(5)
Cl4P1Cl7
P2O1C8A
P2C3C4
90.34(5)
119.3(2)
117.1(2)
122.1(3)
118.2(3)
119.7(3)
121.6(3)
122.3(3)
119.9(3)
116.1(3)
C3C4C4A
C3C4C9
C4AC4C9
C4C4AC5
C4C4AC8A
O1C8AC4A
O1C8AC8
Cl4P1Cl8
Cl4P1Cl9
Cl5P1Cl6
Cl5P1Cl7
Angle
Angle
Angle
Cl1P2O1C8A
C3P2O1C8A
81.8(2)
39.4(2)
P2O1C8AC4A
C3C4C9C14
27.5(4)
46.3(4)
C4AC4C9C10
C3C4C4AC8A
49.8(4)
14.5(5)
P2C3C4C4a, from which the P2,C3 and O1,C8a atoms
deviate to the same side but by different distances
by 1.0201(8) and 0.0272(8) , respectively. The axial
bond P Cl1 is longer then the equatorial bond
P2 Cl2. The dihedral angle between the P2C3C4C4a
and O1C8aC4aC4 planes is 14.8(3) . The 4-Ph sub-
stituent is appreciably turned relatively to the P2C3
C4C4a plane [torsion angle 49.8(4) ], which makes
unlikely conjugation between the Ph ring and C3=C4
bond. The anionic part of the molecule has a regular
octahedron configuration, and the P2 Cl bond lengths
[ 0.6639(8), 0.254(3) and 0.633(2), 0.342(3)
,
respectively]. The Cl1 atom occupies an axial position
and deviates from the P2C3C4C4a and O1C8aC4aC4
planes by 1.8222(8) and 2.5973(8) , respectively.
The Cl2 atom occupies an equatorial position and
deviates from the P2C3C4C4a and O1C8aC4aC4 planes
span the range of 2.114 2.151(1)
(principal bond
lengths and bond and torsion angles in molecule V are
listed in the table).
Analysis of intermolecular interactions revealed no
classical hydrogen and C H O-type bonds. At the
same time, a lot of short Cl Cl and Cl H contacts
were found. These contacts form a 3D cylindric
domain structure with prevailing chlorine contribu-
tion and with cavities occupied by the carbon carcass
of the phosphinine molecule (Fig. 2).
Fig. 2. Three-dimensional cylindrical domain structure
in the crystal of V.
In the crystal of phosphinine V, there are also
interactions between the phenylene fragments of
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 2 2008

REACTION OF PHOSPHORUS PENTACHLORIDE
neighboring molecules related by a center of sym-
195
metry (1 x, y, 2 z). This short contacts have the
following parameters: The distance between the ring
centers is 4.184(2) , the dihedral angle between the
planes is zero, the angle between the normal to one of
the planes and the vector connecting the ring centers
is 35.82 , and the interplanar spacing is 3.393
.
There are also interactions between the benzene
rings of the substituents at C4 [dimer with a center of
symmetry, symmetry code (1/2 x, 1/2 y, 1 z)].
The parameters of this interaction are as follows: The
distance between the ring centers is 4.369(2) , the
dihedral angle between the planes is zero, the angle
between the normal to the one of the planes and the
vector connecting the ring centers is 40.62 , and
the interplanar specing is 3.316 . As a result, these
interactions form in the crystal of V endless
chains of cations along the a0c diagonal (Fig. 3).
Fig. 3. Chains formed due to
crystal of V.
interactions in the
122 124 C. Mass spectrum, m/z: 310 (C14H9Cl352
O2P) [M]+, 275 [M Cl], [M POCl], 199 [M Cl
PO2]. The melting point and other spectral character-
istics correspond to published data [3].
Thus, the reaction of phosphorus pentachloride
with a cyclic phosphorus derivative, namely, 2,6-di-
chloro-4-phenylbenzo[e][1,2 5]-oxaphosphinine
2-oxide (I) leads to chlorination of the phosphoryl
group, involving consecutive formation of penta- and
tetracoordinate phosphorus derivatives: 2,2,2,6-tetra-
chloro-4-phenylbenzo[e][1,2]oxaphosphinine (IV) and
2,2,6-trichloro-4-phenylbenzo[e][1,2 5]oxaphosphi-
nin-2-ylium hexachlorophosphate (V).
Reaction of 6-chloro-2-hydroxy-4-phenyl[e]-
5
[1,2 ]oxaphosphinine 2-oxide (III) with phos-
phorus pentachloride. A powdered phosphinine III,
4.04 g (0.0138 mol), was added to 3.15 g (0.0151 mol)
of phosphorus pentachloride in 20 ml of benzene. The
reaction mixture was heated under reflux for 1 h under
argon. After cooling, a precipitate formed. The super-
natant liquid was decanted, and the precipitate was
washed with absolute pentane and dried in a vacuum
of 0.1 mm Hg at 70 80 C to obtain 2.86 g (80%) of
oxaphosphinine I.
EXPERIMENTAL
The NMR spectra were recorded on Bruker MSL-
400 (operating at 100.6 MHz for 13C NMR spectra
and at 162.0 MHz for 31P NMR spectra), Avance-600
(1H), and CXP-100 (36.38 MHz, 31P) instruments. The
mass spectra were obtained on a Finnigan MAT
TRACE MS instrument at the ionizing energy 70eV
and ion source temperature 200 C. The sample probe
Reaction of oxaphosphinine III with phosphorus
pentachloride at a 1:3 ratio. A mixture of 8.31 g of
phosphorus pentachloride, 20 ml of benzene, and
3.50 g of oxaphosphinine III was heated under reflux
for 2 h. After cooling, crystals formed and were fil-
tered off, washed with a little benzene, and dried in a
vacuum to obtain 90% (5.86 g) of 2,2,6-trichloro-4-
phenylbenzo[e][1,2 5]-oxaphosphinin-2-ylium hexa-
chlorophosphate (V), mp 171 C. Found Cl, %: 58.21.
C14H9Cl9OP2. Calculated Cl, %: 58.68. 31P NMR
spectrum (C6H6), P, ppm: 63.8 (PIV), 296.1 (PVI).
13C NMR spectrum (C6H6 + D2O in a capillary insert),
C, ppm (J, Hz) (here and hereinafter, in brackes we
1
was heated from 35 to 150 C at a rate of 35 deg min .
Data treatment was performed using the Xcalibur
program.
Reaction of 2,2,2-trichloro-1,3,2-benzodioxa-
phosphole (II) with phenylacetylene. Phenylacety-
lene, 4.17 g, was added to a solution of 10.5 g of
phosphole II in 30 ml of dichloroethane heated to
80 C and stirring with a stream of dry argon fed via a
capillary tube. The rate of addition was so that the
mixture boiled gently. After complete addition, argon
bubbling was continued until the reaction mixture
cooled down to 20 C. The solvent was then removed
by distillation, and the residue was dried in a vacuum
of 0.1 mm Hg at 80 C and treated with a mixture of
pentane and methylene chloride, 10:1. The crystalline
precipitate that formed was filtered off and dried in a
vacuum to obtain 11.0 g (83%) of compound I, mp
specify the shape of the signal in the 13C {1H} NMR
1
3
spectrum): 127.62 [d, JHC (not determined because
of overlapping in the 13C NMR spectrum] (C3, JPC
1
3
153.0 154.0); 156.82 m (br.s) (C4); 121.38 m (d)
(C4a, 3JPCCC 20.0); 130.64 d.d.d (d) (C , JHC 160.0
5 1
4a
5
3
4
163.0, JHC CC 5.5 6.0, JPCCC 2.0); 130.31 (s) (C6);
7
5
5
134.81 d.d (d) (C7, 1JHC 169.5, JHC CC 6.0); 121.69
d.d (d) (C8, 1JHC 168.1, JPOCC 8.0); 148.52 d.d.d (d)
3
7
5
7
3
8
8
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 2 2008

196
MIRONOV et al.
3
3
2
(C8a, JHC CC 10.4, JHC CC 10.4, JPOC 11.4);
reflections, of which 3802 with I > 3 , were measured
on an Enraf Nonius CAD-4 diffractometer at 150 C
( MoK radiation, /2 scanning, 2 max < 52.6 ). No
intensity decay of three reference reflections was ob-
served during measurements. Empirical correction for
5
8a
7
8a
8a
135.25 m (d) (C9, 3JPCCC 25.2); 129.17 d.d.d (s) (C10,
9
1
3
3
10 CC10
12CC10
10
JHC 161.8, JHC
7.0 7.3, JHC
7.0 7.3);
11 CC11
129.56 d.d (s) (C11, JHC 163.4, JHC
7.3);
1
3
11
131.81 d.t (s) (C12, JHC 162.2, JHC
7.3). The
1
3
10CC12
12
1
absorption was applied ( Mo 13.68 cm ). The struc-
melting point of the methylene chloride solvate of
ture was solved by the direct method using the SIR
program [7] and refined first isotropically and then
anisotropically. Hydrogen atoms were revealed by
difference synthesis and refined isotropically at the
final stage. Final divergence factors: R 0.052 and RW
0.068 on 3802 unique reflections with F2 3 . All
calculations were carried out by means of the
MOLEN program package [8] on an AlphaStation 200
computer.
compound V is 189 190 C.
Reaction of oxaphosphinine I with phosphorus
pentachloride. A mixture of 2.09 g of phosphorus
pentachloride, 10 ml of benzene, and 3.11 g of oxa-
phosphinine I was heated under reflux for 2 h. After
cooling, the solvent and POCl3 were removed by dis-
tillation in a vacuum of 12 mm Hg. The residue was
dried in a vacuum 0.1 mm Hg and characterized by
spectral methods. The yield of 2,2,2,6-tetrachloro-4-
phenylbenzo[e][1,2]oxaphosphinine (IV) was 92%,
ACKNOWLEDGMENTS
1
viscous light brown glassy substance. H NMR spec-
The work was financially supported by the Founda-
tion for Support of Domestic Science (project no. MK-
1434.2006.3) and Russian Foundation for Basic
Research (project no. 07-03-00180).
trum (600 MHz, CDCl3 + 20%C6H6, , ppm, J, Hz):
2
3
6.95 d (H3, JPCH 44.9); 7.12 d.d (H8, JH CCH 8.7,
7
8
4
4
JPOCCH 1.4); 7.39 d (H5, JH CCCH 1.8); 7.47 br.d.d
8
7
5
(H7, 3JH CCH 8.7, JH CCCH 1.8); 7.52 7.57 m (C6H5).
4
8
7
5
7
31P NMR spectrum (162.0 MHz, C6H6):
29.7 ppm
REFERENCES
P
(d, JPCH 44.8). 13C NMR spectrum, 13C {1H}
2
1
1. Corbridge, D.E.C., Phosphorus 2000. Chemistry, Bio-
chemistry, Technology, Elsevier: Amsterdam, 2000.
(CDCl31, C, ppm, J, Hz): 127.73 d.d (d) (C3, JPC
3
152.1, JHC 205.1); 157.87 m (d) (C4, JPCC 3.0);
2
3
4
2. Fridland, S.V., and Malkov, Yu.K., Reakts. Metody
Issled. Org. Soedin., 1986, vol. 26, p. 106.
122.09 d.m (d) (C4a, 3JPCCC 20.0); 129.33 br.d (d)
4a
(C5, JHC 167.2, JPCCC 1.1); 130.41 d.d.d (s) (C6,
1
4
5
5
3. Mironov, V.F., Konovalov, A.I., Litvinov, I.A., Gubai-
dullin, A.T., Petrov, R.R., Shtyrlina, A.A., Zyabliko-
va, T.A., Musin, R.Z., Azancheev, N.M., and Il’ya-
sov, A.V., Zh. Obshch. Khim., 1998, vol. 68, no. 9,
p. 1482.
3
2
2
8
6
7
6
5 6
JHC CC 11.0, JHC C 4.0, JHC C 4.0); 132.77 d.d.d
(d) (C7, JHC 167.6, JHC CC 6.0, JPOCCC 1.7);
1
3
4
7
5
7
7
121.54 d.d (d) (C8, JHC 167.0, JPOCC 5.9); 152.61
1
3
8
8
m (d) (C8a, 2JPOC 14.4); 136.31 m (d) (C9, JPCCC
3
8a
9
27.0); 128.27 d.m (s) (C10, JHC 162.0); 128.94 d.d
1
4. Varaksina, E.N., Mironov, V.F., Mezentsev, S.A., Mu-
sin, R.Z., and Konovalov, A.I., Zh. Obshch. Khim.,
2006, vol. 76, no. 3, p. 513.
10
(s) (C11, JHC 162.3, JHC
6.7 7.0); 130.39 d.t
7.3). Mass spectrum,
1
3
11 CC11
11
(s) (C12, 1JHC 161.8, JHC
3
12
10
12
m/z: 329 [M Cl], 294 [MCC 2Cl], 210 [M 2Cl
5. Varaksina, E.N., Mezentsev, S.A., Mironov, V.F., and
Konovalov, A.I., Mendeleev Commun., 2006, vol. 16,
no. 2, p. 100.
POCl], 197 [M
2Cl
POCl
CH].
6. Konovalova, I.V., Mironov, V.F., and Burnaeva, L.M.,
X-ray diffraction analysis. Crystals of compound
V, C14H9Cl3OP PCl6+ 1/2CH2Cl2, monoclinic, at
Zh. Obshch. Khim., 1993, vol. 63, no. 11, p. 2509.
7. Altomare, A., Cascarano, G., Giacovazzo, C., and Vi-
terbo, D., Acta Crystallogr., Sect. A, 1991, vol. 47,
no. 4, p. 744.
150 C: a = 30.23(1), b = 10.323(2), c = 16.990(5)
,
= 120.56(3) , V = 4565(3) 3, Z = 8, M = 616.67,
3
dcalc = 1.79 g cm , F(000) = 2440, space group C2/c
(the solvation methylene chloride molecule is in a
special position at the 2 axis). The intensities of 4989
8. Straver, L.H., and Schierbeek, A.J., MolEN, Structure
Determination System, Nonius B.V., 1994, vol. 1.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 2 2008