A new synthesis of (PhPSe2)2 (woollins reagent) and its use in the synthesis of novel P-Se heterocycles

Article abstract of DOI:10.1002/chem.200500291

A new and improved method for the preparation of (PhPSe₂) ₂ (Woollins reagent (WR), 1) is reported. Reaction of dichlorophenylphosphine with Na₂Se, (prepared from the reaction of elemental selenium and sodium in liquid ammonia) gives WR with excellent purity, high yield and on a larger scale than was previously possible. Four novel phosphorus-selenium heterocycles, including a spirocyclic heterocycle exhibiting a four-membered P₂SeC ring, were obtained from the reaction of WR with two reactive substrates (diphenylcyclopropenone and methyl phenylpropiolate). Useful selenocarbonyl and thiocarbonyl compounds were obtained from the reaction of both WR and Lawesson's reagent with diphenylcyclopropenone. All new compounds were characterised spectroscopically and three demonstrative X-ray structures are reported.

Full text of DOI:10.1002/chem.200500291

FULL PAPER
DOI: 10.1002/chem.200500291
A New Synthesis of (PhPSe2)2 (Woollins Reagent) and Its Use in the
Synthesis of Novel P–Se Heterocycles
Ian P. Gray, Pravat Bhattacharyya, Alexandra M. Z. Slawin, and J. Derek Woollins*[a]
Abstract: A new and improved method
for the preparation of (PhPSe2)2 (Wool-
lins reagent (WR), 1) is reported. Re-
action of dichlorophenylphosphine
with Na2Se, (prepared from the reac-
tion of elemental selenium and sodium
in liquid ammonia) gives WR with ex-
cellent purity, high yield and on a
larger scale than was previously possi-
ble. Four novel phosphorus–selenium
heterocycles, including
heterocycle exhibiting
bered P2SeC ring, were obtained from
the reaction of WR with two reactive
a
a
spirocyclic
four-mem-
and methyl phenylpropiolate). Useful
selenocarbonyl and thiocarbonyl com-
pounds were obtained from the reac-
tion of both WR and Lawessonꢀs re-
agent with diphenylcyclopropenone.
All new compounds were characterised
spectroscopically and three demonstra-
tive X-ray structures are reported.
substrates
(diphenylcyclopropenone
Keywords: heterocycles · phospho-
rus · selenium · Woollins reagent ·
X-ray structure
Introduction
ject of a few reports. Baxter et al.,[6] Bhattacharyya et al.[7]
and Bethke et al.[8a] have reported the selenation reactions
of WR in the synthesis of selenoketenyl complexes and a
range of selenoamides and selenoaldehydes, and Knapp and
Darout very recently described its use for the selenation of
carboxylic acids.[8b] We have also reported the use of WR in
the preparation of novel phosphorus–selenium heterocycles
by the reaction with several organic substrates containing re-
active unsaturated C=C double bonds, CꢀC triple bonds and
CꢀN triple bonds.[9] A further range of novel phosphorus–
selenium heterocycles were prepared by treating WR with
dibasic nucleophiles.[10]
The synthesis and wide variety of reactions of dithiadiphos-
phetane disulfides has been the subject of many reviews, ar-
ticles and communications over many years.[1] In contrast,
their selenium analogues, the diselenaphosphetane disele-
nides, have received very little attention. Shore et al.[2] re-
ported the synthesis of (tBuPSe2)2 from dichloro-tert-butyl-
phosphine and Li2Se2, and, although this compound was
studied crystallographically, its potential chemistry has been
overlooked. Hahn and co-workers were also able to obtain
this compound and its methyl and phenyl analogues[3] from
the reaction of the silyl esters of the triselenophosphonic
acids and DMSO, although no detailed experimental proce-
dure or spectroscopic data was reported. Karaghiosoff and
co-workers[4] and Woollins et al.[5] have reported a range of
diselenaphosphetane diselenides synthesised from the oxida-
tion of the corresponding homocyclic pentamers (PR)5 (R=
Me, Et, 4-Me2NC6H4, An and Ph) by 10 equivalents of ele-
mental selenium, including WR (R=Ph).
Results and Discussion
To date, no suitable general method for the synthesis of dis-
elenaphosphetane diselenides has been established. Here,
we describe a new method that gives WR with excellent
purity and high yield. Reactions were carried out with WR
and two reactive substrates to yield four new phosphorus–
selenium heterocycles and a useful selenocarbonyl com-
pound. As a direct comparison, the reaction between one of
these substrates, diphenylcyclopropenone, and Lawessonꢀs
reagent was performed and gave the analogous thiocarbonyl
compound in high yield.
In recent years, the chemistry of (PhPSe2)2 1 (which has
become known as Woollins reagent, WR) has been the sub-
[a] Dr. I. P. Gray, Dr. P. Bhattacharyya, Prof. A. M. Z. Slawin,
Prof. J. D. Woollins
School of Chemistry, University of St Andrews
St Andrews, Fife KY16 9ST (UK)
Fax : (+44)1334-46-3384
Preparation of Woollins reagent from (PhP)5: WR is usually
E-mail: jdw3@st-and.ac.uk
prepared from the pentamer (PhP)5 by following the litera-
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6221

ture procedure[5c] (Scheme 1). Although this method produ-
ces the desired product, as indicated by the results of micro-
analysis and IR spectra, it has limitations. The pentamer is a
Scheme 1.
highly unpleasant compound, is air-sensitive and has a lin-
gering stench. One other major limitation of this method is
that the pentamer can be readily prepared on a small scale
only (5–10 g), which makes it an unsuitable precursor for
large-scale synthesis.
Preparation of WRfrom PhPCl and Na2Se: We have em-
2
ployed a new method to synthesise WR, producing material
of high purity in high yield. Elemental selenium was added
to sodium metal dissolved in liquid ammonia at À788C, and
was allowed to reflux at À348C. Once the ammonia was re-
moved, Na2Se was obtained as an off-white solid. The am-
monia was replaced by toluene, PhPCl2 was added and the
mixture was heated to reflux. The reaction was filtered to
remove the precipitated NaCl byproduct from the yellow so-
lution. A second portion of selenium was added and reflux
was continued. WR was isolated as red crystals in very high
yield (86%), which were identified by performing micro-
analysis, IR spectroscopy, mass spectrometry, powder dif-
fraction and 31P solid-state NMR spectroscopy. The IR and
solid-state 31P NMR[11] spectra are identical to those ob-
tained for WR by using the previous method, and also to lit-
erature values.
Figure 1. The upper spectrum shows the actual powder diffraction pattern
obtained for 1; the lower spectrum shows the powder diffraction pattern
simulated from single crystal data of 1.
The powder diffraction pattern of the product of this reac-
tion was compared to a theoretical pattern calculated from
single crystal data, unambiguously showing it to be Woollins
reagent (Figure 1). A low intensity peak, due to an unidenti-
fied impurity, was also observed with 2q at 498. A powder
diffraction pattern was also collected for a sample produced
by the pentamer method, and showed it to contain a signifi-
cant amount of red selenium.
Scheme 2.
The use of 31P NMR spectroscopy allows us to monitor
the course of the reaction (Scheme 2). After 18 h of the ini-
tial reflux, a 31P NMR spectrum was recorded (Figure 2),
which shows the presence of both 2 (d=102.3, 101.1, 89.9,
82.9 ppm) and 3 (d=119.0, 108.8, 106.2, 92.8, 90.1 ppm), the
chemical shifts and coupling constants in accordance with
known literature values.[4,5] The spectrum also shows the
presence of the starting PhPCl2 (d=161.5 ppm) and
PhP(Se)Cl2 (d=58.3 ppm) (Figure 2). This suggests that the
reactive heterocycles 2 and 3 are formed by the reaction of
Figure 2. 31P-{1H} NMR spectrum obtained after 18 h of reflux of Na2Se
and PhPCl2 in toluene.
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Synthesis of Novel P–Se Heterocycles
FULL PAPER
PhPCl2 with Na2Se, and upon further addition of selenium,
they are converted to WR.
copy showed that only phenyl protons are present. Unfortu-
nately, the low yield meant that a suitable 13C NMR spec-
trum could not be obtained.
Crystals suitable for X-ray analysis were grown by layer-
ing of a dichloromethane solution with hexane, allowing us
to unambiguously identify the structure of 6 as a four-mem-
bered P2SeC ring fused at the carbon atom to a three-mem-
bered cyclopropene ring (Figure 3). The structure shows
This new method involves the use of the unpleasant di-
chlorophenylphosphine and the potentially hazardous liquid
ammonia; however, it bypasses the handling of the pentam-
er (PhP)5. In addition, it produces a product of high purity,
in higher yield and by a cleaner process, but the real advant-
age of this method is that it can be conducted on a much
larger scale (~150 g).
Reaction of WR with diphenylcyclopropenone: WR and di-
phenylcyclopropenone 4 were stirred together at 1008C in
dichloromethane (in a sealed tube) resulting in a very dark
red solution plus
a small amount of black selenium
(Scheme 3). Column chromatography (silica gel, toluene)
Scheme 3.
Figure 3. The X-ray structure of 6. Selected bond lengths (Š) and angles
À
À
(8) (esdꢀs in parentheses): P(1) Se(1) 2.089(3), P(1) Se(12) 2.265(2),
À
À
À
P(1) C(1) 1.826(10), P(1) C(13) 1.840(9), C(13) C(15) 1.507(12),
produced an orange fraction followed by a purple fraction.
The orange fraction proved to be the expected selenation
product, the selenocarbonyl compound 5. This was isolated
in moderate yield (27%) as an orange, air-stable, solid. The
À
C(14) C(15) 1.290(12), P(1)-Se(12)-P(2) 78.83(9), P(1)-C(13)-P(2)
102.0(4).
1
identity of 5 was confirmed by microanalysis, H, 13C and
that the exocyclic selenium atoms exist in a trans conforma-
tion, consistent with all known four-membered phosphorus–
selenium ring systems of this type. The C=C double bond of
the cyclopropene ring remains unchanged. The P2SeC ring
77Se NMR spectroscopy, IR spectroscopy and mass spec-
trometry. The values obtained matched literature data from
previous studies of this selenocarbonyl species. This com-
pound is of interest in organometallic chemistry as it has
been reported to undergo insertion reactions with metal car-
bonyl compounds.[12]
The second, purple fraction proved to be a new and un-
usual phosphorus–selenium heterocycle 6. This was isolated
in low yield (5%) as a purple solid and was found to de-
grade in the presence of air and moisture over approximate-
ly two weeks. The 31P NMR spectrum of 6 shows a sharp sin-
glet at d=66.1 ppm, accompanied by an unusual pattern of
selenium satellites. There appeared to be three sets of satel-
lites associated with each phosphorus atom, with 31P, 77Se
couplings of 304, 693 and 938 Hz, respectively. Closer in-
spection suggests that the pattern is actually a 1J(31P, 77Se)
adopts a planar conformation that has been shown to be fav-
[2]
oured by similar ring systems, WR,[9a] tBuP2Se4
and
PhP(Se)(m-NPh)P(Se)Ph.[9a] The internal P-Se-P bond angle
in (78.83(9)8) is substantially smaller than in WR
6
(85.45(9)8) and is closer to the values found for
[13]
Ph2P2Se3CMe2 (77.73(7)8) and PhP(Se)(m-NPh)P(Se)Ph[9a]
(75.28(4)8), indicating that the reduction in angle size is due
to the introduction of the smaller heteroatom (C or N).
Only two other examples of P2SeC four-membered rings
[13]
have been discovered; Ph2P2SeCH2 and Ph2P2SeCMe2.[13]
These are consistent with the above structure, but no three-
membered ring has been shown to fuse to such a system.
À
coupling of 304 Hz attributed to the P Se single bonds, and
a
Reaction of Lawessonꢀs reagent with diphenylcyclopropen-
one: As a direct comparison, the reaction between diphenyl-
cyclopropenone and Lawessonꢀs reagent (LR) was per-
formed (Scheme 4) to give 7 as the only product (confirmed
by microanalysis, 1H and 13C NMR spectroscopy, IR spec-
troscopy and mass spectrometry).[11] Like its selenium ana-
logue, 7 has been reported to undergo similar insertion reac-
tions with metal carbonyl compounds.[11] Unlike the corre-
sponding reaction with Woollins reagent, there was no sign
1J(31P, 77Se) coupling of 816 Hz attributed to the P=Se
double bonds, which is split by a 2J(31P, 31P) coupling of
124 Hz. This assignment is further substantiated by
77Se NMR studies. The 77Se NMR spectrum displays two dis-
tinct signals; a doublet at d=À34.1 ppm with a J(31P, 77Se)
1
coupling constant of 820 Hz and a triplet at d=507 ppm
with a J(31P, 77Se) coupling constant of 306 Hz, assigned as
1
1
À
P=Se and P Se, respectively. Results of H NMR spectros-
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J. D. Woollins et al.
Scheme 4.
of the formation of any phosphorus-containing heterocyclic
products. Although this reaction did not produce any novel
heterocycles, it clearly demonstrates a novel and simple
route to this useful thiocarbonyl compound.
Reaction of WR with methyl phenylpropiolate: WR and
methyl phenylpropiolate were heated to reflux in toluene,
resulting in a red solution. The use of column chromatogra-
phy (silica gel, toluene) afforded four phosphorus-containing
fractions, from which compounds 8–10 were obtained in 20–
26% isolated yields (Scheme 5). Compounds 8–10 were
Figure 4. The X-ray structure of 8. Selected bond lengths [Š] and angles
À
À
[8] (esdꢀs in parentheses): Se(1) P(2) 2.096(2), P(2) Se(3) 2.2387(19),
À
À
À
Se(3) Se(4) 2.3286(11), Se(4) C(5) 1.924(6), C(5) C(6) 1.323(9); Se(1)-
P(2)-Se(3) 112.21(9), P(2)-Se(3)-Se(4) 94.78(5), C(5)-Se(4)-Se(3) 96.1(2),
C(5)-C(6)-P(2) 112.3(4), C(6)-C(5)-Se(4) 123.8(5).
10 is assigned as the cis isomer.
This assignment of these iso-
mers is also reinforced by the
13C NMR data, which revealed
the expected differences in
chemical shift and 31P, 13C cou-
pling constants. The 1H NMR
spectra show that in both mole-
cules there are two phenyl
groups and one methoxy group
present.
Scheme 5.
The X-ray structure of 8 con-
firms the formation of a five-
found to be solids that were moderately stable in air, de-
grading over a period of several weeks with the obvious ex-
pulsion of red selenium. They are soluble in chloroform, tet-
rahydrofuran and dichloromethane and insoluble in diethyl
ether and hexane. The mass spectra of these compounds all
contain molecular ion peaks at m/z 506, corresponding to
membered C2PSe2 ring. The
ring is essentially planar with a mean deviation of 0.06 Š;
however, this was not found to be the case for heterocycles
containing similar ring systems formed from the reaction of
WR with dimethyl acetylenedicarboxylate (C2PSe2 and
C2PSe2) and bicyclo[2.2.1]hept-2-ene (C2PSe2), which have
PhPSe3(PhC=C CO2Me), which is supported by microanaly-
ses.
envelope conformations.[9a–c] The Se(3) Se(4) bond length
À
À
À
(2.3266(11) Š) is comparable to the Se Se bond lengths
The 31P NMR spectra of 8 and 10 display sharp singlets at
d=76.0 and 71.4 ppm, respectively, and each signal is ac-
companied by two sets of selenium satellites (789 and
366 Hz for 8, 798 and 343 Hz for 10), indicating that in each
found in (PhPSe)2CH2Se2 (2.338(1) Š)[9b] and PhP(Se)-
Se2(C2{CO2Me}2) (2.359(2) Š)[9c], with the plane of the
phenyl group attached to C(6) lying almost perpendicular to
the central C2PSe2 ring (C(5)-C(6)-C(7)-C(12) torsion angle
of 80.9(10)8).
À
compound there is a P Se single bond and a P=Se double
bond present. This is further substantiated by the 77Se NMR
spectrum, which displays three doublets, due to 31P, 77Se cou-
pling, and indicates the presence of a PhP(Se)-Se-Se chain,
a fragment present in the products obtained from the reac-
tion of WR with dimethyl acetylenedicarboxylate, norborna-
Despite the similarities in the molecular ions and micro-
analyses of 9, and 8 and 10, the spectra of 9 display a some-
what different pattern to those of 8 and 10. The 31P spec-
trum of 9 again displays a sharp singlet (d=85.7 ppm), but
in this case, only one set of selenium satellites is observed,
with a 31P, 77Se coupling constant of 822 Hz. This would indi-
cate the presence of a P=Se double bond and the absence of
diene and norbornene.[9a,b] The X-ray structure of
8
(Figure 4) was obtained unambiguously and shows that the
PhP(Se)-Se-Se chain is attached across the C=C double
bond in a five-membered ring. The structure also shows that
in 8, the ester group is trans to the phosphorus atom, thus
À
any P Se single bonds, therefore, compound 9 must adopt a
different structural motif to that of 8 and 10. The 77Se NMR
spectrum displays a doublet at d=207 ppm with a 31P, 77Se
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Synthesis of Novel P–Se Heterocycles
FULL PAPER
coupling constant of 823 Hz, confirming the presence of a
P=Se bond. There are also two distinct singlets at d=688
and 519 ppm, respectively. The 1H NMR spectrum shows
that the molecule contains two phenyl groups and one me-
Experimental Section
General: Unless otherwise stated, experiments were performed under an
oxygen-free nitrogen atmosphere by using predried solvents and standard
Schlenk techniques. All reagents were purchased from Aldrich, Acros or
Lancaster and were used as received. IR spectra were recorded as KBr
discs in the range 4000–350 cmÀ1 by using a Perkin–Elmer System 2000
Fourier-transform spectrometer; 1H, 31P, 13C and 77Se NMR spectra were
recorded by using a Jeol GSX Delta 270 FT NMR spectrometer. Solid-
state 31P NMR spectra were recorded by using an Infinityplus 500 MHz
solid-state NMR spectrometer. Microanalyses were performed by the
University of St. Andrews microanalysis service. Mass spectra were re-
corded by both the University of St. Andrews mass spectrometry service
and the Swansea mass spectrometry service.
1
thoxy group, with a H,31P coupling constant of 15 Hz.
The X-ray structure of 9 was obtained (Figure 5) and was,
as expected, very different from that of 8. The molecule pos-
sesses
a planar C3Se2 ring, with exocyclic CPh and
PhP(Se)OMe substituents arranged in a cis geometry with
Synthesis
Preparation of (PhP)5: PhPCl2 (8.9 g, 50 mmol) and Mg turnings (1.2g,
50 mmol) were stirred together in THF (50 cm3) for 4 h. Room tempera-
ture was maintained by some external cooling. Acetone (5 cm3) was
added and excess Mg was filtered off. Upon the addition of water (2ꢂ
30 cm3), an oily off-white precipitate formed. The mixture was stirred vig-
orously for 40 min. The product was collected by suction filtration and
dried in vacuo to give a white solid (1.41 g, 26% yield).
Preparation of (PhPSe2)2 (1): From (PhP)5: (PhP)5 (1.01 g, 1.87 mmol)
and selenium (1.49 g, 18.7 mmol) were refluxed with stirring in toluene
(30 cm3) for 5 h. The reaction mixture was allowed to cool to room tem-
perature. The product was collected by suction filtration, washed with
toluene (2ꢂ15 cm3) and dried in vacuo to give a red solid (1.96 g, 78%
yield); IR (KBr disc): n˜ =1433 (s), 1300 (mw), 1280 (w), 1155 (w), 1108
(w), 1078 (s), 994 (m), 917 (w), 841(w), 744 (m), 734 (s), 702(m), 678 (s),
615 (m), 508 (s, br), 486 (s), 430 cmÀ1 (s); elemental analysis calcd (%)
for C12H10P2Se4: C 27.09, H 1.89; found: C 26.62, H 1.80; EIMS (positive
mode): m/z: 534 [M]+.
Figure 5. The X-ray structure of 9. Selected bond lengths [Š] and angles
À
À
À
[8] (esdꢀs in parentheses). Se(1) P(1) 2.096(3), P(1) O(6) 1.591(7), C(2)
À
À
À
Se(3) 1.948(10), Se(3) Se(4) 2.3082(16), Se(4) C(5) 1.895(10), O(6)
À
C(6) 1.469(13), C(2) O(2) 1.202(12); C(1)-P(1)-Se(1) 113.1(3), C(5)-
C(1)-P(1) 126.6(8), C(2)-C(1)-P(1) 112.9(7), C(2)-C(1)-P(1) 112.9(7),
O(2)-C(2)-C(1) 126.4(9), O(2)-C(2)-Se(3) 119.7(8), C(1)-C(2)-Se(3)
113.9(7), C(2)-Se(3)-Se(4) 92.4(3), C(5)-Se(4)-Se(3) 91.1(3), C(1)-C(5)-
Se(4) 122.0(8)C(5)-C(1)-C(2) 120.3(9).
Preparation of (PhPSe2)2 (1): From PhPCl2: Na (1.2g, 52.2mmol) was
dissolved in liquid NH3 (50 cm3) at À788C. Se (2.061 g, 26.1 mmol) was
added, resulting in a dark red mixture. After 15 min of stirring, the NH3
was allowed to evaporate and was replaced by toluene (50 cm3). An
excess of PhPCl2 (6.60 cm3) was added and refluxed for 64 h. The prog-
ress of the reaction was monitored by 31P NMR analysis. Se (3.435 g,
43 mmol) was added and the mixture was refluxed for 3.5 h. The product
was collected by suction filtration, washed with toluene (2ꢂ15 cm3) and
dried in vacuo to give a red solid (5.68 g, 82% yield); 31P NMR (solid
state): d=18.7 ppm (s); IR (KBr disc): n˜ =1434 (s), 1302(mw), 1280 (w),
1154 (w), 1109 (w), 1077 (s), 994 (m), 917 (w), 744 (m), 734 (s), 704 (m),
679 (s), 614 (m), 508 (s, br), 486 (s), 432cm À1 (s); elemental analysis
calcd (%) for C12H10P2Se4: C 27.09, H 1.89; found: C 27.12, H 1.41;
EIMS (positive mode): m/z: 534 [M]+.
respect to one another. The structure shows that, in contrast
to 8, the ester group of the starting material has not re-
mained unchanged, with the methoxy group having migrat-
ed to form a bond to the phosphorus atom. The data ob-
tained from the 13C NMR spectrum of 9 is that expected for
this structure.
À
À
In 8 and 9, the C Se (1.895(10), 1.948(10) Š) and P Se
bond lengths (ca. 2.10 Š for P=Se double bonds and 2.24 Š
This reaction can be performed on a scale 20 times greater than that de-
scribed above, and by taking suitable handling precautions. Attempts
were made to repeat this procedure using a) Li (0.362g, 52.2mmol) and
b) (nBu4N)BH4 (13.421 g, 52.2 mmol) instead of Na, however, both at-
tempts proved unsuccessful.
À
for P Se single bonds) and the angles at internal selenium
atoms (91.1(3) to 96.1(2)8) are consistent with those found
for similar ring systems. There are no notable intermolecular
contacts within either structure.
Reaction of WR with diphenylcyclopropenone—synthesis of 5 and 6:
WR (1), (0.2g, 37.3 mmol) and diphenylcyclopropenone (0.154 g,
74.6 mmol) were stirred in dichloromethane (3 cm3) at 1008C in a sealed
tube for 5 min, producing a dark red solution plus a tiny amount of black
solid (selenium). Column chromatography (silica gel, toluene) produced
an orange fraction and a subsequent purple fraction. These were dried in
vacuo and produced an orange solid, 5, and a purple solid, 6.
Compound 5 (0.054 g, 27% yield, based on ketone); 1H NMR (CDCl3):
d=7.61–8.25 ppm (m, 10H; Ph); 13C NMR (CDCl3): d=173.1 (s, C=Se),
159.9 (s, Ph C-1), 134.6 (s, p-Ph), 132.4 (s, m-Ph), 129.7 (o-Ph), 122.8 ppm
(s, C-Ph); 77Se NMR (CDCl3): d=330.0 ppm (s); IR: (KBr disc): n˜ =3463
(s, br), 1780 (m), 1596 (m), 1360 (m), 1331 (s), 1310 (s), 1287 (s), 1171
(m), 764 (s), 685 cmÀ1 (s); elemental analysis calcd (%) for C15H10Se: C
66.92, H 3.74; found: C 66.74, H 3.51; EIMS (positive mode): m/z: 2 70
[M]+.
Conclusion
We have described a new method for the preparation of
WR, which gives a product of excellent purity and high
yield, and which can be applied to syntheses on a much
larger scale than that previously employed. Reactions were
carried out with Woollins reagent and two reactive sub-
strates (diphenylcyclopropenone and methyl phenylpropio-
late) to yield four new isolable phosphorus–selenium hetero-
cycles, including the novel spirocyclic compound 6.
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J. D. Woollins et al.
Compound 6 (0.012g, 5% yield, based on WR): Yellow crystals suitable
for X-ray analysis were grown by layering a dichloromethane solution
with hexane; 1H NMR (CDCl3): d=7.16–7.37 ppm (m, 20H; Ph);
31P NMR (CDCl3): d=66.1 ppm (s, 1J(31P, 77Se)=304.2Hz, 1J(31P, 77Se)=
815.5 Hz), 2J(31P, 31P)=124.4 Hz; 77Se NMR (CDCl3): d=À34.1 (d, 1J-
128.3 (s, C-Ph-m), 128.0 (d, 3J(31P, 13C) 14.5 Hz, P-Ph-m), 127.2 (s, C-Ph-
p), 52.3 ppm (d, 2J(31P, 13C) 5.2Hz, O CH3); 31P NMR (CDCl3): d=
85.7 ppm (s, 1J(31P, 77Se)=821.7 Hz); 77Se NMR (CDCl3): d=687.5 (s,
C(=O)Se), 518.0 (s, C(Ph)Se), 207.0 ppm (d, 1J(31P, 77Se)=822.5 Hz, P=
Se); selected IR data (KBr): n˜ =1638 (s, C=O), 546 cmÀ1 (m, P=Se); ele-
mental analysis calcd (%) for C16H13O2PSe3: C 38.04, H 2.59; found: C
37.69, H 2.34; EIMS (positive mode): m/z: 506 [M]+.
1
(31P, 77Se)=820.2 Hz), 506.9 ppm (t, J(31P, 77Se)=306.1 Hz); IR (KBr disc):
n˜ =3048 (s), 1445 (m), 1435 (s), 1305 (w), 1086 (s), 754 (s), 727 (m), 706
(m), 685 (s), 541 cmÀ1 (s, P=Se); elemental analysis calcd (%) for
C27H20P2Se3: C 50.41, H 3.13; found: C 50.11, H 3.04; EIMS (positive
mode): m/z: 643 [M]+.
Compound 10 (0.070 g, 25% yield); 1H NMR (CDCl3): d=8.18 (m, 2H;
Ph), 7.48 (m, 8H; Ph), 3.37 ppm (s, 3H, CH3); 13C NMR (CDCl3): d=
165.7 (d, 2J(31P, 13C) 10.4 Hz, C=C-Ph), 164.3 (d, 2J(31P, 13C) 18.7 Hz, C=
O), 133.2(d, 1J(31P, 13C) 74.9 Hz, P-Ph C-1), 132.8 (d, 4J(31P, 13C) 3.1 Hz, P-
Ph-p), 131.5 (d, 3J(31P, 13C) 13.5 Hz, P-Ph-m), 131.3 (s, C-Ph-p), 129.0 (s,
C-Ph-o), 128.7 (d, 3J(31P, 13C) 10.8 Hz, C-Ph C-1), 128.6 (d, 2J(31P, 13C)
15.6 Hz, P-Ph-o), 128.5 (s, C-Ph-m), 126.5 (d, 1J(31P, 13C) 71.6 Hz, P-C=
C), 52.3 ppm (s, OCH3); 31P NMR (CDCl3): d=71.4 ppm (s, 1J(31P, 77Se)=
798.3 and 342.8 Hz); 77Se NMR (CDCl3): d=532.0 (d, 2J(31P, 77Se)=
7.2Hz, C-Se), 420.6 (d, 1J(31P, 77Se)=343.3 Hz, P-Se), À25.0 ppm (d, 1J-
Reaction of Lawessonꢀs reagent with diphenylcyclopropenone—synthesis
of 7: LR (0.133 g, 37.3 mmol) and diphenylcyclopropenone (0.154 g,
74.6 mmol) were refluxed in toluene (3 cm3) for 3 min, producing a
brown/orange solution. Column chromatography (silica gel, toluene) pro-
duced a yellow fraction. This was dried in vacuo to give a yellow solid
1
(0.121 g, 74% yield); H NMR (CDCl3): d=7.25–7.85 ppm (m, 10H; Ph);
13C NMR (CDCl3): d=178.5 (s, C=S), 153.8 (s, Ph C-1), 133.8 (s, p-Ph),
132.1 (s, m-Ph), 129.6 (o-Ph), 122.9 ppm (s, C-Ph); IR (KBr disc): n˜ =
(31P, 77Se)=798.7 Hz, P=Se); selected IR data (KBr): n˜ =1707 (s, C=O),
À1
3449 (s, br), 1780 (m), 1595 (m), 1352(s), 1331 (s), 1314 (m), 1298 (m),
À
1233 (s, C O), 539 cm (m, P=Se); elemental analysis calcd (%) for
À1
1172(m), 762(s), 688 cm
(s); elemental analysis calcd (%) for C15H10S:
C16H13O2PSe3: C 38.04, H 2.59; found: C 39.01, H 2.44; EIMS (positive
mode): m/z: 506 [M]+.
C 81.04, H 4.53; found: C 80.72, H 4.26; EIMS (positive mode): m/z: 2 2 2
[M]+.
X-ray crystallography: Table 1 list details of data collections and refine-
ments. Data for 6 and 8 were collected at 293 K, and for 9 at 125 K by
using a Bruker SMART (sealed tube) system. Intensities were corrected
for Lorentz-polarisation and for absorption. The structures were solved
by direct methods. The positions of the hydrogen atoms were idealised.
Refinements were obtained with full-matrix least-squares based on F2 by
using SHELXTL.[14,15]
Reaction of WR (1) with methyl phenylpropiolate: A mixture of Wool-
lins reagent (0.300 g, 0.56 mmol) and methyl phenylpropiolate (0.18 cm3)
in toluene (7 cm3) was heated at reflux for 21 h resulting in a red solu-
tion. After cooling to room temperature, the solution was subjected to
column chromatography (silica gel, toluene) and afforded successively
yellow, orange (8), yellow (9) and orange (10) eluates. Compounds 8–10
were precipitated as yellow (8 and 9)
or orange (10) solids following the ad-
dition of hexane to dichloromethane
solutions.
Table 1. Details of the X-ray data collections and refinements for 6, 8 and 9.
Compound
6
8
9
Compound
8 (0.073 g, 26% yield):
formula
C27H20P2Se3
yellow, block
0.2ꢂ0.1ꢂ0.05
monoclinic
C2/c
13.6894(8)
11.0398(5)
33.605(2)
90
C16H13O2PSe3
yellow, block
0.15ꢂ0.1ꢂ0.1
monoclinic
P21/c
9.6996(10)
9.4792(9)
19.1924(19)
90
C16H13O2PSe3
yellow, plate
0.16ꢂ0.04ꢂ0.02
monoclinic
P21/n
11.041(4)
7.068(3)
22.564(8)
90
101.306(7)
90
1726.7(11)
4
505.11
1.943
6.486
968
7042
2432(0.02508)
0.0882, 0.2010
Yellow crystals suitable for X-ray anal-
ysis were grown by layering of a di-
chloromethane solution with hexane;
1H NMR (CDCl3): d=8.02(m, H2 ;
Ph), 7.44 (m, 3H; Ph), 7.18 (m, 3H;
Ph), 7.01 (m, 2H; Ph), 3.61 ppm (s,
3H; CH3); 13C NMR (CDCl3): d=
178.6 (d, 3J(31P, 13C) 9.3 Hz, C=O),
162.9 (d, 2J(31P, 13C) 26.0 Hz, C-C=O),
144.5 (d, 1J(31P, 13C) 60.2Hz, P- C(Ph)=
C), 133.7 (d, 3J(31P, 13C) 10.4 Hz, C-Ph-
o), 132.8 (d, 3J(31P, 13C) 12.5 Hz, P-Ph-
m), 131.1 (d, 1J(31P, 13C) 70.6 Hz, P-Ph
crystal colour, habit
crystal size [mm3]
crystal system
space group
a [Š]
b [Š]
c [Š]
a [8]
b [8]
90.496(2)
90
5078.5(5)
8
100.033(2)
90
1737.6(3)
4
g [8]
V [Š3]
Z
Mr
643.25
1.683
4.485
2512
505.11
1.931
6.445
968
4
C-1), 129.7 (d, J(31P, 13C) 5.2Hz, C-Ph-
1 [gcmÀ3
]
m), 129.6 (d, 4J(31P, 13C) 5.2Hz, P-Ph-
p), 128.9 (d, 2J(31P, 13C) 29.1 Hz, C-Ph
C-1), 128.5 (d, 2J(31P, 13C) 14.5 Hz, P-
Ph-o), 127.8 (s, C-Ph-p), 53.3 ppm (s,
OCH3); 31P NMR (CDCl3): d=
76.0 ppm (s, 1J(31P, 77Se)=789.2and
365.9 Hz); 77Se NMR (CDCl3): d=
525.8 (d, 2J(31P, 77Se)=9.5 Hz, C-Se),
341.4 (d, 1J(31P, 77Se)=367.2Hz, P-Se),
m [mmÀ1
F(000)
]
measured reflns.
10621
8260
independent reflns. (Rint
final R1, wR2 [I>2s(I)]
)
3584(0.0301)
0.0623(0.1445)
2368(0.0588)
0.0461, 0.1074
26.8 ppm (d, 1J(31P, 77Se)=796.3 Hz, P=Se); selected IR data (KBr): n˜ =
À1
À
1742(s, C =O), 1224 (m, C O), 523 cm (m, P=Se); elemental analysis
calcd (%) for C16H13O2PSe3: C 38.04, H 2.59; found: C 38.47, H 2.30;
[1] a) M. P. Cava, M. I. Levinson, Tetrahedron 1985, 41, 5061; b) R. A.
Cherkasov, G. A. Kutyrev, A. N. Pudovik, Tetrahedron 1985, 41,
2567; c) M. Jesberger, T. P. Davis, L. Barner, Synthesis 2003, 1929;
d) B. S. Pedersen, S. Scheibye, N. H. Nilsson, S. O. Lawesson, Bull.
Soc. Chim. Belg. 1978, 87, 223; e) H. Hoffman, G. Schumacher, Tet-
rahedron Lett. 1967, 8, 2963; f) M. R. St. J. Foreman, A. M. Z.
Slawin, J. D. Woollins, J. Chem. Soc. Dalton Trans. 1996, 3653;
g) M. R. St. J. Foreman, A. M. Z. Slawin, J. D. Woollins, Heteroat.
Chem. 1999, 10, 651.
EIMS (positive mode): 506 [M]+.
Compound 9 (0.056 g, 20% yield): Yellow crystals suitable for X-ray
analysis were grown by layering of a chloroform solution with hexane;
1H NMR (CDCl3): d=7.90 (m, 2H; Ph), 7.64 (m, 2H; Ph), 7.48 (m, 6H;
Ph), 3.28 ppm (d, 3H; 3J(31P, 1H) 15.0 Hz, CH3); 13C NMR (CDCl3): d=
194.6 (d, 2J(31P, 13C) 17.6 Hz, C=O), 178.6 (d, 2J(31P, 13C) 10.4 Hz, C=C-
Ph), 138.8 (d, 1J(31P, 13C) 120.8 Hz, P-C=C), 136.5 (d, 3J(31P, 13C) 3.1 Hz,
C-Ph C-1), 132.1 (d, 2J(31P, 13C) 12.5 Hz, P-Ph-o), 130.4 (s, C-Ph-o), 130.0
(d, 1J(31P, 13C) 121.4 Hz, P-Ph C-1), 129.6 (d, 4J(31P, 13C) 4.2Hz, P-Ph- p),
[2] J. T. Shore, W. T. Pennington, M. C. Noble, A. W. Cordes, Phospho-
rus Sulfur Relat. Elem. 1988, 39, 153.
6226
www.chemeurj.org
ꢁ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2005, 11, 6221 – 6227

Synthesis of Novel P–Se Heterocycles
FULL PAPER
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Received: March 15, 2005
Published online: August 1, 2005
Chem. Eur. J. 2005, 11, 6221 – 6227
ꢁ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
6227