2,6-Dimethoxyphenylphosphetane sulfide - synthesis, structure and exploratory photochemistry

Article abstract of DOI:10.1016/S0022-328X(99)00210-7

2,6-Dimethoxyphenylphosphetane sulfide has been synthesized by condensation of 2,6-dimethoxyphenylphosphine with 1,3-propanediol ditosylate and treatment of the resulting phosphetane with sulfur. Irradiation at 254 nm of the phosphetane sulfide was undert

Full text of DOI:10.1016/S0022-328X(99)00210-7

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Journal of Organometallic Chemistry 585 (1999) 167–173
2,6-Dimethoxyphenylphosphetane sulfide—synthesis, structure and
exploratory photochemistryꢀ
Hu Qian a, Peter P. Gaspar a,*, Nigam P. Rath b
a Department of Chemistry, Washington Uni6ersity, St. Louis, MO 63130-4899, USA
b Department of Chemistry, Uni6ersity of Missouri-St. Louis, St. Louis, MO 63121, USA
Received 1 March 1999
Abstract
2,6-Dimethoxyphenylphosphetane sulfide has been synthesized by condensation of 2,6-dimethoxyphenylphosphine with 1,3-
propanediol ditosylate and treatment of the resulting phosphetane with sulfur. Irradiation at 254 nm of the phosphetane sulfide
was undertaken to determine the mode of photodissociation and the types of reactive intermediates produced. Evidence is
presented for the formation of both the corresponding arylphosphinidene sulfide ArPꢀS and the methylene(thioxo)phosphorane
ArP(S)ꢀCH2 as transient species. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Phosphetane sulfide; Phosphinidene sulfide; Methylene(thioxo)phosphorane
The ring-strain embodied in three- and four-mem-
bered heterocycles is known to facilitate their dissocia-
tion to reactive intermediates. In the silicon series
siliranes have been found to be excellent precursors for
the thermal and photochemical generation of silylenes
R2Si: [1], while siletanes have long been known to yield
silenes R2SiꢀCR2 [2]. Germiranes are generally unstable
[3], but germetanes seem capable of decomposing to
either germylenes R2Ge: or germenes R2GeꢀCR2, as the
following example suggests [4]:
In recent work it has been demonstrated that phos-
phiranes and their chalcogenides are also efficient pre-
cursors for the photochemical and pyrolytic generation
of phosphinidenes and their chalcogenides [5–9]:
Comparison of the reactivity of phosphinidenes R–P
(isolobal with nitrenes) and their chalcogenides R–PꢀO
and R–PꢀS (long recognized as isolobal with carbenes)
[10] is of current interest because the differences in the
symmetry of their HOMOs should lead to differences in
reaction pathways if transition-state structures maxi-
mize frontier orbital overlap [11]. While differences
between ‘carbene-like’ R–PꢀZ and ‘nitrene-like’ R–P in
the mechanisms of such reactions as addition to p-
bonds remain to be firmly established, the evidence is
mounting [9], and the prospects for the control of
phosphinidene reactivity by altering their HOMO ener-
gies are excellent.
ꢀ Dedicated to Professor Alan Cowley, on the occasion of his 65th
birthday.
* Corresponding author.
In the present work a chalcogenide of an arylpho-
sphetane has been synthesized employing improvements
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00210-7

168
H. Qian et al. / Journal of Organometallic Chemistry 585 (1999) 167–173
[5] in the condensation of primary phosphines with diol
ditosylates originally developed by Oshikawa and Ya-
mashita [12]. It has been established that the P–C bond
forming steps are clean SN2 processes occurring with
inversion of absolute configuration, and thus, optically
active phosphiranes could be synthesized from optically
pure chiral diols [13]. This strategy was extended by
Marinetti and coworkers to the synthesis of chiral
phosphetanes [14].
The phosphetanes examined in this work were syn-
thesized by the following route:
Fig. 2. ORTEP drawing of the X-ray crystal structure of 2,6-
dimethoxyphenylphosphetane sulfide, S pseudo-equatorial, 25% ther-
mal ellipsoids.
with a pucker angle of 17.6° for 1-L-menthyl-2,2,4,4-te-
tramethylphosphetane oxide [17]. A pucker angle of
24.4° has been calculated for unsubstituted pho-
sphetane [18]. A larger pucker angle should favor extru-
In Figs. 1 and 2 ORTEP drawings of the X-ray crystal
structure of the phosphetane sulfide are shown [15].
Table 1 gives crystal data and structure refinement
parameters and Table 2 presents selected bond lengths
and angles. The phosphetane ring is puckered by 28.5°
(dihedral angle between the planes C1–P1–C3 and
C1–C2–C3) with S pseudo-axial and 34.2° with S
pseudo-equatorial [16]. Such puckering of more highly
substituted phosphetane chalcogenides has been noted,
sion of
a
phosphinidene chalcogenide upon
photodissociation, relative to (2+2) cycloreversion.
The reverse of such a cycloreversion, the (2+2) cy-
cloaddition of phospha-alkene metal complexes to
olefins has been accomplished by Marinetti and Mathey
[19].
Solutions of the phosphetane sulfide were irradiated
at 254 nm in order to determine what modes of
photodissociation operate. In separate experiments, a
0.05 M solution of 2,6-dimethoxyphenylphosphetane
sulfide in a 1:1 v/v mixture of CH2Cl2 and MeOH and
a 0.1 M solution of the phosphetane sulfide in CD3OD
were irradiated at 254 nm. As indicated in Table 3,
cyclopropane and propylene were detected in both ex-
periments, and ethylene was found in the fully deuter-
ated solvent that permitted its observation. The
coproduct of unimolecular photoelimination of cyclo-
propane and propylene from the phosphetane sulfide
should be 2,6-dimethoxyphenylphosphinidene sulfide
ArPꢀS, and evidence for its formation is given below.
The coproduct of unimolecular extrusion of ethylene
from the phosphetane sulfide should be the
methylene(thioxo)phosphorane ArP(S)ꢀCH2, and evi-
dence for its formation has also been found. Photoin-
duced ring expansion of the phosphetane sulfide can
also be inferred. Complete characterization of the prod-
ucts has thus far been thwarted by difficulties in their
purification from small-scale experiments.
Fig. 1. ORTEP drawing of the X-ray crystal structure of 2,6-
dimethoxyphenylphosphetane sulfide, S pseudo-axial, 25% thermal
ellipsoids.

H. Qian et al. / Journal of Organometallic Chemistry 585 (1999) 167–173
169
Table 1
In both solvent systems, a major product observed in
the 31P-NMR spectrum displays a chemical shift (20.8
ppm) appropriate for a tricordinate phosphorus com-
pound. Since a major product in both solvent systems
was revealed by GC–MS analysis to be isomeric with
the starting material, ring-expansion appears to be one
of the photoprocesses [21].
Crystal data and structure refinement parameters
Empirical formula
Formula weight
Temperature (K)
Crystal system
Space group
Unit cell dimensions
C11H15O2PS
242.26
298(2)
Orthorhombic
Pnma
The product chemical shift at 75.6 ppm formed in all
the irradiations is consistent with a methanol adduct of
ArP(S)ꢀCH2, or its rearrangement product [22], and
GC–MS analysis revealed the formation of a product
corresponding in mass to the addition of CH3OH and
CD3OD, respectively to ArP(S)ꢀCH2 when these isoto-
pomers were employed as solvent. Alcohol adducts of
methylene(thioxo)phosphoranes generated by other
routes, PhP(S)ꢀCPh2 [23], 2,6-Me2PhP(S)ꢀCPh2 [24],
and PhP(S)=CH2, [25], have been observed.
,
a (A)
12.1641(2)
29.7785(4)
10.1361(1)
90
90
90
3671.59(9)
12
1.315
0.374
0.44×0.40×0.33
1.37–25.00
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
V (A )
3
,
Z
Dcalc. (Mg mm−3
)
Absorption coefficient (mm−1
)
Crystal size (mm3)
Theta range for data collection
The hydrocarbon coproducts of photolysis leave little
doubt concerning the reactive intermediates formed
upon fragmentation of the phosphetane sulfide, and the
spectroscopic data recorded for the phosphorus-con-
taining products of trapping experiments lend support
to the following reaction scheme. However, it must
remain tentative until the rearrangement and trapping
products are fully characterized.
(°)
Index ranges
−155h515, −375k537,
−125l512
37930
3302 [Rint=0.14]
None
Reflections collected
Independent reflections
Absorption correction
Refinement method
Full-matrix least-squares on
F2
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I\2|(1)]
R indices (all data)
3291/0/212
1.007
R1=0.0466, wR2=0.0947
R1=0.0886, wR2=0.1097
0.0020(5)
Extinction coefficient
Largest difference peak and hole 0.296 and −0.434
−3
,
(e A
)
Consumption of the phosphetane sulfide was much
more rapid in the mixed solvent system, in which the
31P chemical shift for the methanol adduct of the
arylphosphinidene sulfide ArPH(S)OMe (55.9 ppm) [20]
was observed. The corresponding deuterated adduct
was not observed when the solvent was pure CD3OD.
Table 2
What is clear, however, is that the ultraviolet irradia-
tion of phosphetane derivatives is a promising new
source of reactive species.
,
Selected bond distances (A) and angles (°) for compound 1
S Pseudo-axial
S Pseudo-equatorial
,
Bond lengths (A)
P(1)–C(4)
P(1)–S(1)
P(1)–C(1)
P(1)–C(3)
1.800(3)
1.9523(10)
1.821(3)
1.813(3)
1.537(4)
1.541(4)
P(1%)–C(4%)
P(1%)–S(1%)
P(1%)–C(1%)
P(1%)–C(3%)
C(1%)–C(2%)
C(2%)–C(3%)
1.801(4)
1.9605(14)
1.832(3)
1.832(3)
1.532(4)
1.531(4)
1. Experimental
1.1. General data
C(1)–C(2)
C(2)–C(3)
All preparative reactions were carried out in flame-
dried glassware under an atmosphere of dry nitrogen or
argon. Photolyses were carried out in a Rayonet RS
photochemical reactor (model number RPR-208, 120
W radiated power) equipped with low-pressure mercury
Bond angles (°)
C(3)–P(1)–C(1)
C(2)–C(1)–P(1)
C(2)–C(3)–P(1)
C(4)–P(1)–S(1) 114.24(9)
C(4)–P(1)–C(1) 111.82(12)
C(4)–P(1)–C(3) 113.11(12)
78.67(12)
88.6(2)
88.7(2)
C(3%)–P(1%)–C(1%)
C(2%)–C(1%)–P(1%)
C(2%)–C(3%)–P(1%)
C(4%)–P(1%)–S(1%)
C(4%)–P(1%)–C(1%)
C(4%)–P(1%)–C(3%)
76.7(2)
88.5(2)
88.5(2)
109.69(12)
108.71(13)
108.71(13)
1
lamps emitting 254-nm radiation. H-, 13C-, and 31P-
NMR spectra were recorded on Varian XL-300, Gem-
ini-300 (13C 75.4 MHz, 31P 121.4 MHz), XL-500 (13C

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H. Qian et al. / Journal of Organometallic Chemistry 585 (1999) 167–173
Table 3
Results of 254 nm irradiation of 2,6-dimethoxyphenylphosphetane sulfide
Solvent
Time (min)
Conversion (%)
31P chemical shifts of products l
Hydrocarbon yields (%)
cyclo-(CH2)3
Propene
Ethylene
a
MeOH–CD2Cl2
CD3OD
CD3OD
40
40
130
190
83
17
76
89
4.2, 20.8, 55.9, 75.6
20.8, 70.4, 75.6
20.8, 49.8, 70.4, 75.6
20.8, 49.8, 70.4, 75.6
22
20
30
32
15
14
17
17
17
25
26
CD3OD
a Not determined because of overlapping peaks in the 1H-NMR spectrum employed to determine yields.
125 MHz, 31P 202.3 MHz) and XL-600 (13C 250 MHz)
spectrometers. 85% H3PO4 was employed as an external
standard for 31P spectra. Recorded yields are based on
starting materials consumed and were determined by
integration of 31P-NMR spectra. Combined gas chro-
matography–mass spectrometry was performed on a
Hewlett-Packard Model 5890 Series II instrument fitted
with a Quadrex 25-m×0.32 mm capillary column
coated with 0.5 mm polymethyl (5% phenyl) silicone
bonded phase, connected to a Model 5971 Mass Selec-
tive detector (quadrupole mass filter), mass spectra
recorded above m/e 40, ionization energy 70 eV.
1.4. 2,6-Dimethoxyphenylphosphine
A total of 13.8 g (0.1 mol) 1,3-dimethoxybenzene,
11.6 g (0.1 mol) TMEDA, and 150 ml THF were placed
in a 500-ml three-necked flask equipped with a 100-ml
pressure equalizing dropping funnel, magnetic stirring
bar, septum, and a nitrogen inlet, and the reaction flask
was cooled to 0°C. A total of 42 ml 2.5 M n-BuLi
(0.105 mol) in hexane was slowly added to the mixture,
which was then stirred for 4 h at room temperature
(r.t.). The resulting yellowish solution of 2,6-
dimethoxyphenyllithium was transferred by cannula to
a 250-ml pressure-equalizing dropping funnel (flushed
with nitrogen) that was installed on a 500-ml three-
necked flask equipped with a magnetic stirring bar,
nitrogen inlet and septum. 15.7 g (0.1 mol) ClP(OEt)2
and 100 ml THF were placed in this flask which was
equipped with a magnetic stirring bar, septum, and
nitrogen inlet, and was cooled to 0°C. The solution of
2,6-dimethoxyphenyllithium was added slowly, and
then the reaction mixture was stirred overnight. The
mixture was concentrated to ca. 50 ml, and 300 ml
pentane was added to precipitate LiCl. After filtration
and removal of solvent, 24 g of an orange liquid was
obtained whose 31P-NMR spectrum indicated that \
90% of the phosphorus containing compounds present
was the target diethyl(2,6-dimethoxyphenyl)phosphite
(l 163, MS (EI) m/e (relative intensity) 258 (M+, 100),
227 (32), 201 (84), 183 (93), 171 (53), 155 (38), 141
(83)). This crude product was employed in the next
step. LiAlH4 (0.8 g, 0.2 mol) and 200 ml THF were
placed in a 1 l three-necked flask equipped with a 150
ml pressure-equalizing dropping funnel, mechanical
stirrer, and a Friedrichs condenser capped with a nitro-
gen inlet. After the slurry was cooled to −30°C with
stirring, 19.4 g (0.179 mol) Me3SiCl was added drop-
wise, and the mixture was allowed to warm to r.t. and
stirred for 1.5 h. The mixture was cooled to 0°C and a
1.2. Materials
Benzene, THF, ether, and pyridine were dried by and
distilled from benzophenone sodium ketyl under a ni-
trogen atmosphere immediately before use. Calcium
hydride was the drying agent for pentane, cyclohexane,
and hexane. CH2Cl2 was distilled from P2O5. The fol-
lowing were employed as received, except as noted:
2-bromomesitylene (Aldrich, 99%), ethylene (Aldrich,
99.9%), PCl3 (Aldrich, 98%, distilled under N2 before
use), P(OEt)3 (Aldrich, 98%), n-BuLi (Fisher, 1.6 M or
Aldrich, 2.5 M in hexane), LiAlH4 (Aldrich, 95%),
1,3-propanediol (Sigma, 98%), 1,3-dimethoxybenzene
(Aldrich, 99%, distilled under N2 from Na before use),
TMEDA (Aldrich, 99%, dried with n-BuLi and distilled
under N2), p-toluenesulfonyl chloride (Aldrich, 98%),
H2O2 (Aldrich, 30%), H2O2-urea complex (Aldrich,
98%), sulfur (Mallinckrodt, sublimed), benzene-d6
(Aldrich, 99.6%), CD2Cl2 (Aldrich, 99.95%), CD3OD
(Aldrich, 99.8%), CDCl3 (Aldrich, 99.8%), Ph3P
(Aldrich, 99%), W(CO)6 (Aldrich, 99%), BH3–SMe2
(Aldrich, 2.0 M in Et2O).
1.3. Chlorodiethylphosphite ClP(OEt)2
solution of 23.3
g
(0.090 mol) diethyl(2,6-
dimethoxyphenyl)phosphite in 100 ml THF was added
slowly. The mixture was stirred for 6 h, and 31P-NMR
indicated complete conversion of the phosphite and a
primary phosphine as the major product. After excess
LiAlH4 was quenched with 40 ml degassed MeOH, and
Chlorodiethylphosphite ClP(OEt)2 was synthesized as
a colorless liquid, b.p. 56–58°C/30 Torr in a 53% yield
(50 g) using the method of Cook et al [26]: 31P-NMR
(121.4 MHz, CDCl3) 166 (lit. [27] l 165). There is a ca.
10% Cl2POEt impurity: 31P-NMR l 178 (lit. [21] 177).

H. Qian et al. / Journal of Organometallic Chemistry 585 (1999) 167–173
171
filtration, the yellowish filtrate was concentrated and
product collected by reduced pressure distillation 90–
100°C/ca. 1 Torr, yielding 10.2 g (55%) of crude
product. Recrystallization from hexane at −20°C pro-
vided colorless crystals, m.p. 39.5°C of 2,6-dimeth-
oxyphenylphosphine: 31P-NMR (121.4 MHz, C6D6) l
light-yellow crystals were obtained by recrystallization
from 1:9 CH2Cl2–EtOAc: m.p. 119–120°C; 31P-NMR
(121.4 MHz, CD2Cl2) l 50.1; 1H-NMR (300 MHz,
CD2Cl2) l 1.90–3.28 (m, 6H, CH2CH2CH2), 3.88 (s,
6H, OCH3), 6.61 (d, 1H, JH–H=8.4 Hz, m-CH), 6.63
(d, 1H, JH–H=8.4 Hz, m-CH%) 7.42 (t, 1H, JH–H=8.4
Hz, p-CH); 13C{1H}-NMR (150.9 MHz, CD2Cl2) l
1
−172 (t, JH–P=205.2 Hz); H-NMR (300 MHz, C6D6)
l 3.32 (s, 6 H, OCH3), 4.06 (d, 2 H, JP–H=210.6 Hz,
PH2), 6.25 (d, 2H, JH–H=8.4 Hz, m-H), 7.02 (t, 1H,
J
16.8 (d, JP–C=19.9 Hz, CH2CH2CH2), 38.5 (d, JP–C
=
53.4 Hz, CH2CH2CH2), 56.3 (s, OCH3), 104.7 (d, JP–
C=4.7 Hz, m-C), 111.8 (d, JP–C=61.0 Hz, ipso-C),
134.0 (s, p-C), 161.1 (s, o-C); MS (EI) m/e (relative
intensity) 242 (M+, 97), 199 (25), 185 (37), 167 (100),
153 (44). Anal. Calc. for C11H13O2PS: C, 54.53; H, 6.25;
observed: C, 54.51; H, 6.35%.
H–H=8.2 Hz, o-H); 13C{1H}-NMR (75.4 MHz,
CD3CN) l 57.0 (s, OCH3), 105.1 (d, JP–C=17.4 Hz,
m-C), 118.6 (s, ipso-C), 130.8 (s, p-C), 161.6 (d, JP–C
=
4.6 Hz, o-C); MS (EI) m/e (relative intensity) 170 (M+,
100), 153 (23), 138 (46), 109 (20).
1.5. 1,3-Propanediol ditosylate
2. X-ray diffraction study
1,3-Propanediol ditosylate was synthesized using the
method of Corey and Mitra [28] in a 69% yield (68 g,
recrystallized from EtOH), m.p. 125–126°C (lit. [23]
126–127°C).
A crystal of appropriate dimensions was mounted on
a glass fibers in a random orientation. Preliminary
examination and data collection were performed em-
ploying a Bruker SMART Charge Coupled Device
(CCD) Detector system single crystal X-ray diffrac-
tometer using graphite monochromated Mo–Ka radia-
1.6. 2,6-Dimethoxyphenylphosphetane sulfide
,
tion (u=0.71073 A) equipped with a sealed tube X-ray
To 2.28 g (5.93 mmol) 1,3-propanediol ditosylate in a
250 ml Schlenck flask containing a magnetic stirring
bar and capped with a septum was added 1.00 g (5.88
mmol) 2,6-dimethoxyphenylphosphine and 150 ml
THF. Then 7.5 ml of 1.6 M n-BuLi was added drop-
wise by syringe to the stirred reaction mixture which
had been cooled to 0°C. The mixture was stirred for 60
min and a 31P-NMR spectrum of an aliquot revealed
that no primary phosphine (l −172) remained, and a
single major product (l −10.8) had been formed. After
excess n-BuLi was quenched with 0.1 ml (0.8 mmol)
Me3SiCl and excess Me3SiCl solvent was removed un-
der vacuum, 150 ml pentane was added to precipitate
lithium salts. Filtration and evaporation of the solvent
yielded 1.05 g (86%) 2,6-dimethoxyphenylphosphetane
as a slightly yellow liquid containing no other phospho-
rus compounds: 31P-NMR (121.4 MHz, CD2Cl2) l
−10.86. Further purification was discouraged by its
instability.
To a solution of the crude 2,6-dimethoxyphenylpho-
sphetane (1.05 g, 5.00 mmol) in 30 ml CH2Cl2 con-
tained in a 100 ml flask with a magnetic stirring bar was
added 1 g (31 mmol) sulfur. After 45 min of stirring
31P-NMR spectroscopy indicated that the phosphetane
(l −10.86) was completely converted to a new product
(l 50.1). The solvent was removed under vacuum, and
addition of 5 ml CH2Cl2 dissolved the product and
allowed the excess sulfur to be removed by filtration,
yielding 1.185 g (98%) crude product as a light-yellow
oil. Chromatography on silica gel with CH2Cl2 eluent
yielded 0.72 g (60%) of a light-yellow solid, from which
source at r.t. Preliminary unit cell constants were deter-
mined with a set of 45 narrow frames (0.3° in 6) scans.
A typical data set collected consists of 4028 frames of
intensity data collected with a frame width of 0.3° in 6
and counting time of 15 s per frame at a crystal to
detector distance of 4.930 cm. The double pass method
of scanning was used to exclude any noise. The col-
lected frames were integrated using an orientation ma-
trix determined from the narrow frame scans. SMART
and SAINT software packages [29] were used for data
collection and data integration. Analysis of the inte-
grated data did not show any decay. Final cell con-
stants were determined by a global refinement of xyz
centroids of 8192 reflections (qB25°). Collected data
were corrected for systematic errors using SADABS [30]
based upon the Laue symmetry using equivalent reflec-
tions. The integration process yielded 37 930 reflections
of which 3302 (2qB50°) were independent reflections.
Crystal data and intensity data collection parameters
are listed in Table 1.
Structure solution and refinement were carried out
using the SHELXTL-PLUS software package [31]. The
structure was solved by direct methods and refined
successfully in the space group Pnma with z=12 sug-
gesting 1.5 molecules per asymmetric unit. No missing
symmetry was confirmed by Platon. Full-matrix least-
squares refinement was carried out by minimizing
ꢀw(F2o−F2c)2. The non-hydrogen atoms were refined
anisotropically to convergence. The hydrogen atoms
were treated using appropriate riding model (AFIX

172
H. Qian et al. / Journal of Organometallic Chemistry 585 (1999) 167–173
m3). The final residual values were R(F)=4.66% for
2104 observed reflections [I\2|(I)] and wR(F2)=
10.97%; s=1.07 for all data. Structure refinement
parameters are listed in Table 1. Selected geometrical
parameters are listed in Table 2. A projection view of
the molecule with non-hydrogen atoms represented by
25% probability ellipsoids showing the atom labeling is
presented in Figs. 1 and 2.
Table 3. The largest peak in the GC–MS integrated
ion current mass chromatogram (C2H4 and C3H6 not
detectable under these conditions) corresponds to a
product isomeric with the starting phosphetane
sulfide, retention time 13.2 versus 13.9 min: MS (EI)
m/e (relative intensity) (M+, 99), 199 (29), 185 (28),
167 (100), 153 (42), 63 (29). The second largest
product peak has a parent mass compatible with an
adduct of CH3OH to ArP(S)ꢀH2: MS (EI) m/e (rela-
tive intensity) 246 (M+, 8), 232 (65), 200 (52), 185
(100), 167 (43), 153 (35), 139 (25), 123 (13), 109 (19),
93 ((19), 77 (15), 63 (25).
3. Ultraviolet irradiation of 2,6-dimethoxyphenylpho-
sphetane sulfide
3.1. Gas mixture preparation
5. Irradiation of 2,6-dimethoxyphenylphosphetane sulfide
in CD3OD
A small quantity of propene was prepared sweeping
the product with a slow stream of nitrogen from a
reaction mixture prepared by dropping freshly dis-
tilled 2-bromopropane into a gently refluxing 4 M
solution of NaOH in EtOH [32]. The propene was
collected in a liquid nitrogen trap from which it was
transferred by trap-to-trap distillation on a vacuum
line to a 4 mm o.d. Pyrex tube into which ethylene
was condensed from a metal cylinder. A small quan-
tity of cyclopropane was prepared by sweeping the
product with a slow nitrogen stream from a reaction
mixture prepared by dropping freshly distilled 1,3-di-
bromopropane into a suspension of zinc powder in a
gently refluxing mixture of 75% EtOH and 25% H2O
[33].
The cyclopropane was collected in a liquid nitrogen
trap and transferred to the pyrex tube containing
ethylene and propene. CD3OD was added as solvent
and the solution degassed to 10−4 Torr by three
freeze-pump-thaw cycles. The 1H-NMR spectrum of
this sample facilitated detection and yield determina-
tion for ethylene (l 5.34), propylene (l 1.65–1.70,
4.80–5.04, and 5.71–5.86) and cyclopropane (l 0.31)
among the irradiation products.
A 0.1 M solution prepared by dissolving 10 mg
(0.041 mmol) 2,6-dimethoxyphenylphosphetane sulfide
crystals in 0.4 ml CD3OD was placed in a mm o.d.
quartz tube which was sealed with a torch after the
solution was degassed by three freeze–pump–thaw
cycles at 10−4 Torr. The sample was irradiated at
254 nm, 15°C, and 31P-NMR spectra were recorded
before irradiation and after 40, 130, and 190 min.
NMR data are included in Table 3. The largest
product peak in the GC–MS integrated ion current
mass chromatogram was the same compound isomeric
with the starting phosphetane sulfide found upon irra-
diation in CH3OH–CDCl2. The mass spectrum of the
second most abundant ‘heavy’ product (under condi-
tions not allowing detection of C2H4 and C3H6) is
compatible with an adduct of CD3OD to
ArP(S)ꢀCH2: MS (EI) m/e (relative intensity) 250
(M+, 4), 236 (57), 203 (28), 202 (29), 201 (32), 185
(100), 167 (33), 153 (33), 139 (24), 123 (14), 110 (15),
96 (27), 77 (14), 63 (23).
6. Supplementary material
For the X-ray crystal structures illustrated in Figs.
1 and 2 and the subjects of Tables 1 and 2, complete
listings of atomic coordinates and the geometrical
parameters for the non-hydrogen atoms, positional
and isotropic displacement coefficients for hydrogen
atoms, anisotropic displacement coefficients for the
non-hydrogen atoms have been deposited with the
Cambridge Crystallographic Data Center (CCDC
116777). Copies of this information may be obtained
free of charge from The Director, CCDC, 12 Union
Road, Cambridge, CB2 1EZ, UK (Fax: +44-1223-
336-033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk). Tables of calculated and
observed structure factors are available in electronic
format.
4. Irradiation of 2,6-dimethoxyphenylphosphirane sulfide
in 1:1 CH3OH–CD2Cl2
A 0.05 M solution of 2,6-dimethoxyphenylpho-
sphetane sulfide was prepared by dissolving 5.0 mg
(0.021 mmol) of the crystalline compound in a mix-
ture of 0.2 ml CD2Cl2 and 0.2 ml CH3OH. The solu-
tion was placed in a 4 mm o.d. quartz tube, which
was sealed with a torch after three cycles of freeze–
pump–thaw degassing at 10−4 Torr. This sample was
irradiated at 254 nm at 15°C for 40 min. 31P- and
1H-NMR spectra were recorded before and after irra-
diation, and indicated 83% conversion of the pho-
sphetane sulfide. The NMR results are included in

H. Qian et al. / Journal of Organometallic Chemistry 585 (1999) 167–173
173
[16] The two molecules in the unit cell differ in geometry as indicated
in Table 1.
Acknowledgements
[17] A. Marinetti, L. Ricard, Tetrahedron 49 (1993) 10291.
[18] S.M. Bachrach, J. Phys. Chem. 93 (1989) 7780.
[19] A. Marinetti, F. Mathey, J. Chem. Soc. Chem. Commun. (1990)
153.
[20] P.P. Gaspar, H. Qian, A.M. Beatty, D.A. d’Avignon, J.L.-F.
Kao, J.C. Watt, N.P. Rath, Tetrahedron, in press.
[21] For 1-phenyl-2-thiaphospholane and 1-phenyl-2-thiaphophori-
nane 31P-NMR (CDCl3) 22.3 and 4.8, respectively: S.
Kobayashi, M. Suzuki, T. Saegusa, Bull. Chem. Soc. Jpn. 58
(1985) 2153.
We thank Dr Frank Borkenhagen for valuable exper-
imental advice. This work has received financial sup-
port from National Science Foundation Grant
CHE-9632897.
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.
.